Method to Achieve Print-Bake Fixation for Inkjet Printing of Dyes

Method to achieve print-bake fixation for inkjet printing of dyes

A dissertation submitted to The University of Manchester for the Master of Philosophy in the Faculty

of Engineering Physical Sciences

2015

Renwei Tian

School of Materials University of Manchester

Contents List of figures ...... 3 List of tables ...... 5 ABSTRACT ...... 6 DECLARATION ...... 7 ACKNOWLEDGEMENT ...... 8 COPYRIGHT STATEMENT ...... 9 1. Introduction ...... 11 1.1 Literature review ...... 12 1.1.1 Cotton ...... 12 1.1.2 Historical background of reactive dye ...... 24 1.2 Research purposes ...... 48 2. Research Methodology ...... 50 2.1 Convert commercial dye (MX-2G Blue) to phosphonic acid containing dye .... 50 2.1.1 Synthesis of Dye 1 ...... 50 2.1.2 Synthesis of Dye 2 ...... 57 2.1.3 Synthesis of Dye 3 ...... 60 2.2 Application of modified dye to cotton ...... 61 2.2.1 Pad-batch method ...... 61 2.2.2 Inkjet printing via modified dye ...... 66 2.3 Inkjet printing via Desktop inkjet printer ...... 71 2.3.1 Pre-treatment of cotton fabrics ...... 73 2.3.2 Desktop inkjet printing process ...... 74 3 Evaluate modified dye performance ...... 76 3.1 Colour strength measurement for inkjet printed sample fabrics via spectrophotometer ...... 76 3.1.1 Measure samples...... 77 3.2 Tensile Test ...... 78

3.2.1 Tensile Procedure ...... 80 3.3 Ultraviolet-Visible spectrophotometry ...... 81 3.3.1 Sample measurement ...... 82 3.3.2 Standard solution make up ...... 84 3.4 Fourier Transform Infrared Spectroscopy ...... 85 3.4.1 FT-IR measuring procedure...... 86 3.5 Thin layer chromatography ...... 87 3.5.1 Producing the chromatogram ...... 89 3.5.2 Rf Values ...... 92 4 Results and Discussion ...... 94 4.1 Dye analysis ...... 94 4.1.1 Thin layer chromatography ...... 94 4.1.2 FT-IR ...... 97 4.2 Application of synthesised phosphonic acid containing dye to cotton ...... 98 4.2.1 Effect of Catalyst type and Concentration on dye fixation via Pad-bake method ...... 98 4.2.2 Effect of Catalyst type and Concentration on dye fixation via Inkjet printing ...... 108 4.2.3 Effect of printing method on colour strength ...... 112 4.3 Effect of pretreatment and baking process on tensile strength ...... 118 5. Conclusion ...... 122 5.1 Recommendations for future research...... 125 5.2 Future of Inkjet printing ...... 126 6. Reference ...... 127 7. Appendix…………………………………………………………………………137

List of figures

Figure.1.1 Cotton boll after opening (https://oecotextiles.wordpress.com/tag/cotton-boll/) ...... 13 Figure 1.2 Cross-sectional view of a cotton fibre (Textile Fibers, © 2013 Cotton Incorporated)...... 14 Figure 1.3 Longitudinal convolutions of a cotton fibre (Plant Fibres for Textile and Technical Applications, 2013) ...... 15 Figure 1.4 Cross-sectional view of a bundle of cotton fibres (Plant Fibres for Textile and Technical Applications, 2013) ...... 16 Figure 1.5 D-configuration glucose unit (Journal of Biomaterials and Nanobiotechnology, 2013) ...... 18 Figure 1.6 β-(1-4) glycosidic bond (Identification of a chemical indicator of the rupture of 1,4-β-glycosidic bonds of cellulose in an oil-impregnated insulating paper system. 2007) ...... 18 Figure 1.7 cellulose molecules chain (http://staff.concord.org/~btinker/workbench_web/unitIV_revised/cellulose/ cellulose6.html) ...... 19 Figure 1.8 The structure and the inter- and intra-chain hydrogen bonding pattern in cellulose...... 20 Figure 1.9 Positions in the cellulose structure for chemical reactions. (Recent developments in spectroscopic and chemical characterization of cellulose . 21 Figure 1.10 Configurations of the crystalline and amorphous regions in cellulose microfibril. (Cellulose nanomaterials review: structure, ...... 21 Figure 1.11 Unit cells for cellulose structures Iα (a). (Parallel-up structure ...... 22 Figure 1.12 Unit cells for cellulose structures Iβ (b). ((Parallel-up structure ...... 23 Figure 1.13 Relative configuration of Ia with respect to Iβunit cell (Macromolecules, 1991) ...... 23 Figure 1.14 The components of a Reactive dye. (The dyeing of textile fibres, 1992) ...... 25

Figure 1.15 Procion Indigo Navy MX-2G (http://www.worlddyevariety.com/reactive-dyes/reactive-blue-109.html) ... 26 Figure 1.16 Nucleophilic substitution for reactive dye (The dyeing of textile fibres, 1992) ...... 27 Figure 1.17 2-Bowl padder mangle (http://www.indiantextilejournal.com) ...... 31 Figure 1.18 Textile Printing by Conventional Manual Methods ...... 33 Figure 1.19 Textile Printing by Inkjet printing Methods ...... 34 Figure 1.20 Formation of droplet (Textile digital printing technology, 2005) ...... 36 Figure 1.21 Formation of droplet (www.huntsman.com) ...... 37 Figure 1.22 Unfixed dye test (The Surface Designer's Handbook，2006) ...... 39 Figure 1.23 Reactive dyeing effluents emission (http://news.cnhubei.com/xw/gn/201302/t2464886.shtml) ...... 41 Figure 1.24 Treatment of the effluents (http://www.thermaxindia.com) ...... 42 Figure 1.25 Phosphonic acid derivative react with cellulose ...... 44 Figure 1.26 Synthesis of Procion T dyes ...... 44 Figure 1.27 Iso-urea ...... 45 Figure 1.28 Phosphonic acid anhydride ...... 45 Figure 1.29 Formation of the phosphonic anhydride ...... 46 Figure 1.30 Cationic adduct generated by dye phosphonate and react with cotton ...... 46 Figure 1.31 Monophosphonic acid 1 ...... 47 Figure 1.32 Diphosphonic acid derivative 2 ...... 47 Figure 1.34 Fixation to cellulose and hydrolysis of the dye...... 48

List of tables

Table 1.1 Average cotton fibers chemical composition (STRUCTURE AND ENGINEERING OF CELLULOSES, 2010) ...... 17 Table 1.25 The fixation (%) yield of reactive dyes (The Chemistry Of Synthetic Dyes, 1996) ...... 40 Table 3 Standard solution concentration at corresponding Absorbance...... 100 Table 4 Absorbance at the wavelength of strongest absorption for wash off solutions (not batched) ...... 101 Table 5 Absorbance at the wavelength of strongest absorption for wash off solutions (batched) ...... 101 Table 6 Concentration for wash off solution (not batched) ...... 102 Table 7 Concentration for wash off solution (batched)...... 102 Table 8 Volume measurement for not batched sample wash off solutions ...... 103 Table 9 Volume measurement for batched sample wash off solutions ...... 103 Table 10 Dye being existed in wash off solution (not batched samples) ...... 104 Table 11 Dye being existed in wash off solution (batched samples) ...... 104 Table 12 Dye fixation for not batched samples ...... 105 Table 13 Dye fixation for batched samples ...... 105 Table 14 Lightness and total colour difference for inkjet printing samples treated with Cyanamide ...... 108 Table 15 Lightness and total colour difference for inkjet printing samples treated with Dicyandiamide ...... 108

ABSTRACT

Inkjet printing is predicted as the future for printed textiles. Currently, two main types of colourants exist: dyes, which require extensive post-processing washing treatments but result in substrates with unaltered handle properties; and pigments, which are economically attractive due to their print-dry-sell application sequence, but result in textiles with drastically altered handle.

This project proposes to investigate the use of phosphonic acid reactive dyes for application to cellulosic substrates via inkjet printing.

It is proposed that these dyes may be fixed by dry heat, and may result in levels of fixation sufficiently high to negate the need for washing procedures. This project aims to test these hypotheses.

DECLARATION

I hereby declare that this thesis is my own work and that, to the best of my knowledge and belief, it reproduces no material previously published or written, nor material that has been accepted for the award of any other degree or diploma, except where due acknowledgement had been made in the text.

ACKNOWLEDGEMENT

First and foremost, I would like to express my sincerest gratitude to my supervisor, Dr. Muriel Rigout, for her patient guidance, immense knowledge, enthusiastic encouragement and useful critiques of this research work. I attribute the level of my MPhil degree to her encouragement and effort and without her this project would not have been completed. The words are inadequate to express my feeling to Dr.

Muriel, who expended her youth and knowledge to let me raise my head among the educated people.

Thanks also to all members of the School of Materials for their support whenever needed, in particular, valuable assistances rendered by Dr. Huw

Owens, Mr. Philip Cohen, Mr. Adrian Handley, for training and introducing me to the world of coloration, offering me the resources in running the program, helping me with the testing and being friendly, helpful, making the Lab a pleasant place to work.

I would also like to extend my thanks to all my good friends, who were always willing to help and give support. It would have been a lonely life in Manchester without them.

Finally, I wish to thank the two unbreakable shields, who have stood against destructive storms for my sake, who have offered all they could have like burning candles lighting up the path of my life, who are my parents, I appreciate all they have done for me.

The author of this dissertation (including any appendices and/or schedules to this dissertation) owns any copyright in it (the ―Copyright‖) and s/he has given The University of Manchester the right to use such

Copies of this dissertation, either in full or in extracts, may be made only in accordance with the regulations of the John Rylands University Library of Manchester. Details of these regulations may be obtained from the

Librarian. This page must form part of any such copies made.

The ownership of any patents, designs, trade marks and any and all other intellectual property rights except for the Copyright (the ―Intellectual

Property Rights‖) and any reproductions of copyright works, for example graphs and tables (―Reproductions‖), which may be described in this dissertation, may not be owned by the author and may be owned by third parties. Such Intellectual Property Rights and Reproductions cannot and must not be made available for use without the prior written permission of the owner(s) of the relevant Intellectual Property Rights and/or

Reproductions.

Further information on the conditions under which disclosure, publication and exploitation of this dissertation, the Copyright and any Intellectual

Property Rights and/or Reproductions described in it may take place is

available from the Head of School of Materials.

1. Introduction

Cellulosic fibres can be obtained from various parts of plants--the seed, the stem and the leaf (Franco PHJ, Valadez-Gonzalez M, 2005). Cotton fibre, which is harvested from the seed of the gossypium plant, is the purest source of cellulose, with nearly 90% of the cotton fibre being cellulose (S. Gordon and Y-L. Hsieh, 2007). This research is devoted to the coloration of cotton fibre, the most common cellulosic fibre in textile.

Cotton has a majority share (over 50%) in the global fibre and textile market (P. J. Wakelyn, 2007). It is a fibre obtained from the soft fibre surrounding the seed of Gossypium, a widely grown plant in many parts of the world. It is one of the oldest natural fibre which is still used in today for numerous purposes. Known for its unique properties of biodegradability, high hydrophilicity and excellent mechanical properties, the cotton yarn may be manufactured domestically as well as industrially manufacture (Cousey et al. 1996). There is much evidence provided by the literature and cultural relic indicate that cotton was used in and cultivated as early as in 3000 BC (Art Quill Studio, 2014).

Since the invention of man-made fibres, there has been a decreasing trend in the consumption of cotton. Whereas considering cotton is an almost inexhaustible and biodegradable source of raw material, cotton will still have the leading share in total consumption of natural and man-made fibres in the future.

Textile printing is the most universal and important method used for introducing colour and design to textile fabrics. Considered analytically it is a process of bringing together a design idea, one or more colorants, and a textile substrate, using a technique for applying the colorants with some precision (Miles, 2003).

In this research, we will investigate the use of phosphonic acid reactive dye for application to cellulosic substrates via inkjet printing. Effects on fixation levels, such as batching process, type and concentration of catalyst, will be investigated. Also, assess effects of dye application on strength retention of cotton substrate.1.1 Literature review

This section reviews relevant information related to printing of cellulosic fibre that can be found in the literature. A brief summary of some of the relevant concepts in cotton structure and the chemical reaction inside the cotton and on the surface are presented in this section. Moreover, it is necessary to look at the work that was done previously on cotton printing with reactive dye.

1.1.1 Cotton

Cotton is obtained from the soft fibre surrounding the seed of gossypium plants. During growth, the blossoms fall off and bolls form. There are approximately 20 seeds inside each boll. Afterward the seed hairs (cotton fibre) come out and begin to grow. When the growth ceases, the boll bursts open, blooming the seed hairs (Fig 1.1). When the boll splits, the

moisture inside it evaporates and the wall of the fibre shrinks and collapses. As drying proceeds, the fibre of cotton develops convolutions.

As soon as the bolls open the cotton must be picked immediately (Mather et al. 2011).

Figure.1.1 Cotton boll after opening (https://oecotextiles.wordpress.com/tag/cotton-boll/)

1.1.1.1 The morphological structure of cotton

The cotton fibre is a single biological cell with a multilayer structure. It is composed of four main parts, as shown on Figure 1.2; form the outside of the fibre to the inside are cuticle, primary wall, secondary wall, and lumen (Smole et al. 2013). During the fibre formation, the microfibrils first stack together to from the primary wall. As the cell grows to the full length of the fibre, secondary walls are deposited inside the primary wall little by little, simultaneously leaving a hollow tube (lumen) at the centre

(Xiangwu Zhang, 2013).

Figure 1.2 Cross-sectional view of a cotton fibre (Textile Fibers, © 2013 Cotton Incorporated). The cuticle layer is a tough protective layer covering the primary wall with a thin waxy film, which is composed of wax and pectin materials.

More specifically, it protects the fibre from potential mechanical and chemical damage.

The primary wall consists of numerous fibrils spiraling around the fibre axis. Fibrils are simply packs of cellulose chains (Parker, 1998).

Chemical analysis of the primary wall indicates that it consist of some cellulose, wax, protein and non-cellulosic substances. It is a tough protective layer which forms during the early days of growth.

The secondary wall, which has several layers of fibrils, is also composed of cellulose and makes up 90% of the total fibre weight. These layers of fibrils are formed during the second growth stage. The fibrils of the second wall are laid down together in a near-parallel arrangement. The layers of fibrils packed in a spiral formation along its length, and reverse in direction at regular intervals. As seen in Fig 1.3, this arrangement

result to each single cotton fibre having twists (convolutions) along its length. The convolutions are very important to the longitudinal strength and fibre-to-fibre cohesion in spun textile yarns (Cohen and Johnson,

2012). It helps the fibres interlock when it is spun into a yarn. Long fibres have about 300 convolutions per inch and short fibres have 200 or less

(Parker, 1998).

Figure 1.3 Longitudinal convolutions of a cotton fibre (http://ecrimescenechemistrymiller.wikispaces.com/RLG%2C+RY%2C+RW%2C+KS%2C+DH+-+7+ fibers, 2009) The lumen is the central channel in the cotton fibre, it surrounded by the wall. It carries nutrients of the cotton during growth and also contains the dried residues of cell protoplasm (Parker, 1998). The lumen wall provides the inner cell boundary (Wakelyn et al.2007).

The cross-section of the fibre reveals it is kidney shaped due to the cotton fibre drying out. Specifically during drying the fibre shrinks, collapses, and the lumens become smaller. The lumen contents evaporate after the boll splits. After drying and collapsing of the fibre, the area of lumen is reduced to about 5% of the total area. After bursting of the mature boll, the fibre wall shrinks and collapses. On drying and collapsing of the fibre, the cylindrical cross-section is converted into a convoluted ribbon form with the flattening of the ribbon. The structure of the wall allows higher shrinkage in the perpendicular direction to the fibrils than in the parallel direction. Due to the spiral structure of the fibrils, the collapse results in the twisting of the fibre about its axis.

Figure 1.4 Cross-sectional view of a bundle of cotton fibres, 2000× magnification (Plant Fibres for Textile and Technical Applications, 2013)

1.1.1.2 Composition of cotton

As mentioned in section 1.1, the main component of cotton is cellulose.

Cotton fibre is composed of more than 90% cellulose along with wax,

proteins and other orangic matters (Table 1.1).

Table 1.1 Average cotton fibers chemical composition (STRUCTURE AND ENGINEERING OF CELLULOSES, 2010) However the composition of cotton shows a slight variation in fibre surface and the interior of the fibre. Depending on numerous factors, such as the environment where the cotton has been cultivated, further variation occur (K. Stana-kleinschek et al. 1998).

1.1.1.3 Chemical structure of cotton

In simple terms, cellulose is made of repeated units of the monomer glucose (C6H10O5), see Fig 1.5. The D configuration glucose units (so called anhydroglucose units, AGU) are covalently linked through β-(1–4) glycosidic linkages.

Two adjacent molecules linked together through

a covalent oxygen bond and C1 of one ring and

C4 of the other ring are joined through β-(1-4)

Figure 1.5 D-configuration glycosidic bond (Klemm D et al. 2005), as glucose unit (Journal of Biomaterials and shown in Fig 1.6. Several hundred to over ten Nanobiotechnology, 2013) thousand linked glucose units make up a linear chain within cellulose. Since the

Figure 1.6 β-(1-4) glycosidic bond (Identification of a chemical indicator of the rupture of 1,4-β-glycosidic bonds of cellulose in an oil-impregnated insulating paper system. 2007)

-CH2OH groups are alternating above and below the plane of the cellulose molecule, each glucose unit is rotated 180ºaround the molecular axis, a long and close approach of neighbouring cellulose molecules chain can be produced (Fig 1.7). Apart from this, the cellulose molecules are able to attach close to each other because of the absence of side chains

(Maya Jacob John et al. 2008)

Figure 1.7 cellulose molecules chain (http://staff.concord.org/~btinker/workbench_web/unitIV_revised/cellulose/cellulose6.html) Each glucose residue contains three hydroxyl groups which are able to form hydrogen bonds (inter-chain and intra-chain hydrogen bonding) between adjoining molecules. These groups are polar, meaning the electrons surrounding the atoms are not evenly distributed. The hydrogen atoms of the hydroxyl groups are attracted to the oxygen atoms of the cellulose. The intra-chain hydrogen bonding is dominated by the strong

O3-H······O5 bond (dotted line in Fig 1.6), and results in the linear configuration of the cellulose chain (Robert J. Moon et al. 2011). The intra-chain and inter-chain hydrogen bonding gives cellulose a relatively stable configuration and fibrils high axial stiffness (Klemm D et al. 2005).

As seen on Fig 1.8 one primary hydroxyl group is attached at C6 and two secondary hydroxyl groups attached at C2 and C3. These three hydroxyl groups play an important role in causing the chains to lie together in highly ordered structures and give rise to increasing the rigidity of the structure of cellulose. These hydroxyl groups are also the main chemical characteristics of cellulose which are reactive towards a variety of

chemicals, and this can be made use of in fibre modification, dyeing and finishing (Gordon S et al. 2007).

Figure 1.8 The structure and the inter- and intra-chain hydrogen bonding pattern in cellulose. Solid lines: inter- chain hydrogen bonding. Dotted lines: intra-chain hydrogen bonding (Structure, organization, and functions of cellulose synthase complexes in higher plants, 2007) Furthermore, these groups are hydrophilic in nature, hence giving cellulose the native ability to bond water. Meanwhile, many types of dyes can interact with cellulose through the hydrogen bonding with -OH groups. For instance, reactive dye reacts with the hydroxyl groups at C6 to form a covalent bond with cellulose.

Recently research by Attala and Isogai (R. H. Attala and A. Isogai, 2005) demonstrates that several sites within cellulose can be modified by several kinds of reaction. As shown in Fig 1.9, different positions in the glucose residues can enter into corresponding chemical reactions, such as oxidation, deoxygenation, etc. In this case, we are particularly interested in the reaction of reactive dye with cellulose which occurs via phosphoric attached on the hydroxyl groups, especially the primary group.

Figure 1.9 Positions in the cellulose structure for chemical reactions. (Recent developments in spectroscopic and chemical characterization of cellulose)

1.1.1.4 Crystal structure

The supramolecular structure of cellulose is represented by regions of low order (amorphous regions) and high order (crystalline regions). The degree of crystallinity of cellulose is usually in the range of 40% to 60%, and depends on the origin of the cotton (Fink and Walenta, 1994).

Figure 1.10 Configurations of the crystalline and amorphous regions in cellulose microfibril. (Cellulose nanomaterials review: structure, properties and nanocomposites, 2011) There are several polymorphs of crystalline cellulose, these are cellulose I,

II, III and IV (Moon RJ et al. 2011). The form of cellulose I is the form found in the nature, and is the dominating form in the nature. Its structure

is thermodynamically less stable, hence can be converted to the most stable structure cellulose II by treatment with aqueous sodium hydroxide or by dissolution and precipitation of cellulose (John MJ & Thomas S,

2008). Here we focus on the structure of the cellulose I, the crystal structure found in cotton naturally and hence that present in our samples.

Cellulose I consists of two different polymorphs: a triclinic structure (Iα) and a monoclinic structure (Iβ), which can be found alongside each other

(Hult E-I et al. 2003). With the help of electron microbeam diffraction and co-worked X-ray and neutron diffraction, the investigation of such research revealed the lattice structures of each unit cell. As shown in Fig

1.11. In Iβ there are two individual chains in a lattice unit cell (Fig 1.12), as in Iα only one chain in a triclinic cell. For Iα, the triclinic unit cell parameters are: space group P1, a = 0.672 nm, b = 0.596 nm, c = 1.040 nm, a = 118.081º, b = 114.801º, γ = 80.3751º(Kim U-J et al. 2010).

Figure 1.11 Unit cells for cellulose structures Iα (a). (Parallel-up structure evidences the molecular directionality during biosynthesis of bacterial cellulose, 1997)

For Iβ, the monoclinic unit cell parameters are: space group P21, a =

0.778 nm, b = 0.820 nm, c = 1.038 nm, γ= 96.5º (Kim U-J et al. 2010). 22

Figure 1.12 Unit cells for cellulose structures Iβ (b). ((Parallel-up structure evidences the molecular directionality during biosynthesis of bacterial cellulose, 1997)

Figure 1.13 Relative configuration of Iα with respect to Iβ unit cell (Macromolecules, 1991) The main difference between the Iα and Iβ is the relative displacement of cellulose sheets along the hydrogen-bonded planes in the axis direction

(Fig 1.13).

Iα is a rare form, usually produced by primitive organisms, such as bacteria, algae etc. Whereas higher plants (woody tissues, cotton etc.) consist dominated of the Iβ form (Kim U-J, 2010). Hardy and Sarko

(1996) indicated that the Iα is metastable and can be converted into the more stable Iβ by annealing in alkaline solution.

1.1.2 Historical background of reactive dye

Reactive dyes were not developed until the mid-1950s. ICI (Imperial

Chemical Industries, Ltd) launched triazinyl dyes as the first fully water soluble reactive dye for cellulosic fibres, which could be applied to cellulosic substrates by an exhaust dyeing process and pad fixation process in 1956 (Rattee and Stephen, 1956). This water soluble dye forms a dye-cellulose chemical linkage: a covalent bond. Research have shown that one covalent bond is approximately 30 times as strong as one van der

Waals bond as 70-200 KJ mol-1 energy is required to break one covalent bond (Lewis, 1998). Therefore the dyed substrates have very high levels of wash fastness. The covalent bond between the dye and the cellulose is generally only broken by hydrolysis (Arthur, 2001). Beyond that reactive dyes, especially these used for cellulose dyeing, give a complete range of bright colours to cotton, and provide easy means to achieve level dyeing, which makes the reactive dye class one of the major classes of dyes.

1.1.2.1 Typical structure of reactive dyes

A typical structure of reactive dye molecule includes:

1. The chromophoric groups (chromogen), responsible for the dye’s

colour providing properties. Its molecular structure determines the

interaction with visible light, in particular what portion of the

spectrum is absorbed. . 24

2. The reactive group (s), enabling the dye to react with the hydroxyl

groups in cellulose.

3. A bridging group, linking the reactive group(s) to the chromophoric

group(s). In this way, any change that takes place at the site of the

reactive group will have minimal effects on the colour of the dye

molecule.

4. One or more solubilising groups, attached to the chromophore,

which has the effect of improving the water solubility (John Shore,

2002).

An example of a reactive dye is C.I. Reactive Blue 5:

Figure 1.14 The components of a Reactive dye. (The dyeing of textile fibres, 1992) The early years’ research of reactive dye indicated that depending on the mechanism of formation of the dye-fibre bond, the reactive systems could be classified into two categories. Those dyes containing a nitrogen heterocyclic ring with halogeno (e.g. chlorine) substituents will carry out nucleophilic substitution. Those dyes based on vinylsulphone reactive

systems function by a nucleophilic addition mechanism (John Shore,

1995). The s-triazine ring is a unique nitrogen heterocycle with three electronegative atoms equably distributed around the ring to provide the activation of the halogen atoms attached to the terminal carbon atoms

(Peacock, 1965). In a typical dye of this type, such as Procion Indigo

Navy MX-2G (Fig 1.15), because of the greater electronegativity of N and Cl atoms, the 2- and 4-chloro substituents are susceptible to nucleophilic displacement.

Figure 1.15 Procion Indigo Navy MX-2G (http://www.worlddyevariety.com/reactive-dyes/reactive-blue-109.html) When one of the halogen atoms is appeal to a nucleophile, which can be either a cellulosate ion or a hydroxide ion in the case of the aqueous dyeing process for cellulose, the remainder halogeno substituent’s reactivity is inhibited by the new cellulosyl substituent or the new hydroxyl substituent (Fig 1.16).

Figure 1.16 Nucleophilic substitution for reactive dye (The dyeing of textile fibres, 1992) The former reaction lead to dye fixation on the fibre, the latter lead to dye hydrolysis. This kind of dye is stable in neutral solutions, but subject to hydrolysis under alkaline condition and autocatalytic hydrolysis on the acid side. To keep hydrolysis from happening, a buffer is necessary to ensure the stability during the storage and dyeing processes (J Shore,

1990).

Cellulose is not thought to be a potent nucleophile. However, in the presence of alkali, some of the hydroxyl groups in cellulose carry out acidic dissociation, the Cell-OH groups are encouraged to give Cell-O- groups and it is the cellulosate ion (Cell-O-) that reacts with the dye. It is these that the reactive dye utilises as nucleophilic site; the dye reacts with cellulosate ion by a nucleophilic substitution mechanism. But as mentioned earlier, the dye is susceptible to hydrolysis in alkali medium, on account of the reactive group of the dye reacting with HO- in much the same manner as the cellulosate ion. The hydrolysed dye reduces the fixation efficiency and will have a lower wash fastness on the cellulose fibre (Fig 1.17)

Figure 1.17 Reaction between a reactive dye and water (Colorants and Auxiliaries: Vol 1. 1990) Nevertheless, Studies show that the reaction primarily occurs with the cellulose fibre even though the reactive groups of the reactive dye can react with both cellulose fibre and water. One of the reasons for this is that the rate of the chemical reaction between cellulose and dye is much faster than the reaction with water (100:1) as the concentration of dye in fibre is greater than that of dye in solution. In addition, the cellulosate ion has a greater nucleophilicity than the hydroxyl anion. Therefore, in cellulose dyeing, most of the dye reacts with the fibre, only a small amount of it reacts with the water (Peter J, 1977).

The dichloro-s-triazine dye is highly reactive, therefore it can readily be fixed to cellulosic substrates by a pad-batch method at room temperature or exhausted at 30-40ºC. For the sake of guaranteeing adequate mobility of the reactive dye on the fibre during the exhaustion stage, relatively small chromogens are preferred. Thus the deep tertiary hues who have larger-size chromogens cannot give acceptable performance at low temperature application (J Shore, 2002). These types of hues are usually applied in less reactive forms, such as the monochloro-s-triazine type dyes.

1.1.2.2 Application of reactive dye

Reactive dyes are applied to cellulosic fibres by a variety of methods, including exhaust dyeing, pad-batch, pad-bake/steam, and print-bake/steam. The basic principle of the dyeing process of cotton (at the microscopic scale) can be summarized as below:

1. Adsorption of reactive dye on the surface of cotton. Salt is required

in this stage in order to compensate for the electrostatic repulsion

between the negatively charged fibre surface and the anionic dye and

considerably promote exhaustion of the dye onto the cotton.

2. Reactive dye diffuses in cotton through pores in the structure to

obtain a level distribution of dye. The diffusion depend on the

equilibrium of dye aggregated and monodispersed dye (Zollinger, H.

1991).

3. Dye fixation between cellulose and reactive dye by forming the

covalent bond. The dye molecule bonds to the cellulose fibre and

will not migrate any more.

4. Wash off unfixed and hydrolysed dye and rinse to neutral pH. Make

sure no colour will bleed from the cellulose fibre on subsequent

washing during wear and use. The amount of soap and wash off

temperature varies depending on the required wash fastness level.

1.1.2.2.1 Cold Pad-batch method

This is a semi-continuous method. The well prepared dry cotton fabric is passed through a trough containing the dye solution containing required auxiliaries (such as alkali), then wound onto the pressurised rollers of a padding mangle, as shown in Fig 1.18. The mangle pressure is set to a liquor pick up of typically 60-80%. Thus the cotton fabric is evenly impregnated and the spare dye solution is uniformly squeezed. After that, the wet fabric is wrapped in polythene film to avoid the effects of the atmosphere on the fibre-dye reaction and stored at room temperature for a certain amount of time (4-24 h), depending on the reactivity of the dye selected and the pH of the impregnated fabric. This will allow better dye diffusion and penetration into the fibre. In this research, the padded fabric must be baked to promote further fixation. Typical baking temperatures are between 180ºC -200ºC, and baking usually takes 1 minute. High baking temperatures would cause fabric yellowing, and this may influence the hue of shade. The final step is the thorough wash off process to remove unfixed dye by rinsing with boiled soap solution.

Finally, the washed fabric is dried.

Figure 1.17 2-Bowl padder mangle (http://www.indiantextilejournal.com) The cold pad-batch method offers a simple way of dyeing cotton with reactive dyes. Under the fine control of this process (e.g. constant wet pick-up), good and even shade reproducibility and high colour yields can be obtained. A key problem associated with the application of reactive dyes is the removal of the unfixed dye, which if not removed properly, will adhere to the cellulosic fibre and will come out in subsequent handling. As a result, a low substantivity reactive dye is favoured. This also prevents the dye from rapidly exhausting from the dyeing solution during the fabric passing through the trough. If this happened, the fabric would have a deeper shade at one end than the other end. Yet because a low substantivity dye is preferred, a considerable amount of the dye is left in the solution. In order to achieve a high efficiency utilization of the dye, a lower liquor ratio (amount of water required to the mass of fabric) is preferred. The lower limit of liquor ratio in exhaust dyeing is about 5:1, or possibly 3:1 in specially designed equipment. While Pad-batch method can reach the range 1:1 to 0.5:1 (John Shore, 1995). This kind of behaviour will lead to smaller amounts of water used in Cold Pad-batch 31

method, as well as help avoiding additional loss of dye through hydrolysis. Compared to exhaust dyeing method, Cold Pad-batch process not only save chemicals and water, but also a distinct reduction in energy consumption can be claimed due to dyeing and fixation taking place at room temperature. In addition, low initial investment of equipment and the small space requirements are conspicuous advantages of the Cold

Pad-batch method.

1.1.2.2.2 Inkjet printing on cotton

Cotton printing is one of the most important and versatile techniques used to add colour and pattern to fabrics. Namely it can be seen as the coloration that combines design, engineering and dyeing technology to produce specialty images on textile products.

Inkjet printing is a non-impact printing technique that permits to obtain high quality colour images. By projecting tiny drops of liquid ink (dye liquors) of different colours onto the cellulosic substrate, the imaged pattern can be built up on the surface (Leslie W C Miles, 2003). The colour is bonded with the fibre so that wash and friction resistance can be achieved. More colours can be applied to the fabric in certain patterns, meanwhile in dyeing process the whole fabric is dyed with one colour uniformly.

Textile digital inkjet printing emerged in the 1990s for printing small samples of fabric for niche-market products. The subsequent

developments of inkjet printing over the last decades have been dramatic.

Inkjet printing is presently growing at a rate of 13% per year, and is predicted to grow at a rate of 20% in the following decade (Teunissen et al. 2002). Inkjet printing is one of the fastest growing printing technologies over the conventional printing methods. Inkjet printing offering unique benefits such as simplicity, lower production costs, reduced effluent, less operating skills required, lower energy and water consumption. And beyond that, it is possible to make innovative personalised articles. Among all the fabrics being printed, cotton takes 48% share of the total. In inkjet printing, reactive inks are one of the most popular inks, since the excellent water solubility, good wash fastness and decent brightness (Ross, 2004). Going into the production time scale of a textile print from A to Z, the considerable advantages of design selection and sample printing with inkjet printing can be seen.

Figure 1.18 Textile Printing by Conventional Manual Methods (Textile digital printing technology, 2005) Figure 1.19 indicates a typical time scales of those who have not adopted digital technologies. Even with the help of CAD system and the latest 33

computer technology, the production of the sample print is still the bottleneck. The inkjet printing technology can reduce this bottleneck considerably by reducing the time taken for colour ways and sample selection (Fig 1.20). Thus increases the efficiency of bring the design concepts to the market place greatly.

Figure 1.19 Textile Printing by Inkjet printing Methods (Textile digital printing technology, 2005) A textile inkjet printing system has the following essential elements:

1. One or more inkjet print heads, which are used to generate the

microscopic ink droplets and apply them to the substrate directly.

The types of inkjet system can be divided into two classes,

drop-on-demand (DOD) and continuous stream (CS). Over 85% of

inkjet heads are DOD type, using low viscosity water based inks and

generating drops on demand only when and where they are needed

(Chris Byrne, 2001). In this research, a DOD printer was used. So the

principles of DOD printer will be described later.

2. Inkjet inks, which majority are based on dyes due to wide shade scale

and excellent colour fastness, providing the required colour onto

fibres. They must be formulated with precise characterisitcs and keep

stable in ink cartridge without settling or depositing within the inkjet

nozzle.

3. A printing machine, which is used to feed and present the substrate to

the inkjet head.

4. Software, including printer drivers and colour management systems,

which control the inkjet head and machine.

5. Post treatments are necessary in inkjet printing process. Such as

baking, steaming, washing off.

6. Substrates (media) including paper, coated board, textile fabrics, etc.

Generally these substrates need pre-treatment in order to ensure

proper ink absorption and take up.

1.1.2.2.2.1 Drop-on-demand (DOD) inkjet system

In this technology, the pressure applied to the ink reservoir is not continuous. The pressure is only applied when a droplet is needed. Two main types of print head technologies are available in this category:

Bubble jet system

The bubble jet printer uses a small heating element in the ink reservoir to create pressure droplets on demand. The quantity of ink in each nozzle is heated by a resistive heating element which is controlled by the digital data stream. The ink boils to create a bubble which forces an equivalent

volume of ink droplet through the jet orifice and is ejected to the fabric surface. As shown in Figure 1.21.

Figure 1.20 Formation of droplet (Textile digital printing technology, 2005) Based on the analysis above, this kind of technology is obviously suffered from slow speed. Thermal/bubblejet printer is most suitable for low volume printing. The major problem is the jet nozzle and resistance failure rate resulting from rapid thermal cycling. The high temperature may cause the decomposition of ink components, which leads to the nozzle plugging. For this reason, only thermally stable inks can be used in bubblejet printer.

1.1.2.2.2.2 Piezo jet system

This is the simplest way of producing droplets on demand. In this case, by using Piezo electric effect, small electronic impulses delivered to suitable crystalline materials and cause them to expand. A piezo transducer incorporated in the ink reservoir enables pressure pulses to be created in the ink. Droplets are generated according to the electronic pulse intermittently. Several approaches can be used in order to turn

electrical signal into mechanical pressure pulses to generate ink droplets by PZT (Pbbased Lanthanumdoped Zirconate Titanates). As shown in Fig

1.22. The jet orifice (nozzle) is required to be as close as possible to the fabric surface so as to produce an accurate image.

Figure 1.21 Formation of droplet (www.huntsman.com) This kind of printer has much greater print head life than the thermal/bubblejet printer. Hence the Piezo inkjet printer is suited for high volume printing. As the inks do not need to be heated, the components of ink can be less critical and less expensive. And a wide range of ink formulations can be used in this printer (Miles, 2003). Compared to thermal/bubblejet printer, the droplet size is smaller, resulting in high resolution.

Since cellulose printing accounts nearly 70% of all textiles printing, considerable research has been focused on reactive dye based ink formulations. In the last two decades, we have seen major changes in the global textile printing market: the increasing demand for short process run lengths, fast response, environment friendly and customisation. Also the developing of wide format inkjet printers for small scale printing 37

production, for example, banner and sportswear, has allowed inkjet printing to become more and more common for sample preparation and specialised product printing (Gorgani et al. 2011).

Cotton is commonly printed with commercial reactive dye based inks due to their excellent water solubility, high level wash fastness and brightness of shade. The principles of dyeing cellulose as explained in section

1.1.2.1, are valid for application via inkjet printing, namely diffusion into the fibre and chemical bond formation.

Unlike the conventional cotton printing, in which the reactive dye in the presence of alkali in the print paste is used, the cellulosic fabrics need to be pretreated prior to printing in the inkjet printing. The main reasons to do this are that the reactive dye is more likely to hydrolyse in the ink cartridge when alkali is present. Furthermore such chemicals in the cartridge may corrode the jet nozzle; moreover, "all in" chemicals do not have the desired rheological properties, and thus possibly block the nozzle since the small droplets size (Aston et al. 1993). It is a common practice for cotton fabrics to be padded with a pretreatment paste, which is generally prepared with sodium alginate or chitosan in the presence of sodium bicarbonate and urea (B. Glover, 2005).

After printing, two dye fixation methods can be used on inkjet printed fabrics. For the less reactive dyes, steaming 5 to 15 minutes would be

necessary to obtain level fixation, depending on the steaming temperature.

Printed reactive dye can also be fixed on cellulosic fibre through baking at 160ºC to 180 ºC for up to 3 minutes. Post treatment after printing is a critical step, washing out the unfixed and hydrolysed dye and other chemical residues.

However, reactive dyes, used in dyeing and printing have not largely replaced most of the other classes of dyes for cotton. A reason for this could be unfixed and hydrolysed reactive dye has to be removed thoroughly in order to achieve the satisfactory wash fastness of reactive dyeing. No matter which reactive dye is chosen or how it is processed it, some dye will not be fixed to the fibre. The unfixed dye can be transferred to other fabrics. To prevent bleeding, rubbing off, or back staining of fabric during laundering, unfixed dye must be removed from the dyed fibre.

Figure 1.22 Unfixed dye test (The Surface Designer's Handbook，2006) This is exemplified by the test shown in Fig 1.23. In this test both fabrics were dyed with Procion MX dyes. The fabric on the left was rinsed in cold water only; the fabric on the right was rinsed in cold water, then 39

washed with detergent in hot water and rinsed in boiling water. A piece of damp, undyed cotton fabric was then laid on top of each dry and dyed fabric. Heat and pressure were applied through iron until the cotton had dried. It can be seen that the fabric on the left had unfixed dye and stained the undyed cotton (Holly Brackmann, 2006).

1.1.3 Environmental Footprint

According to analysis of this situation carried out by workers at

Sumitomo (Douthwaite et al. 1996.), the dye-fibre covalent bonding efficiency of different types of reactive dyes can be identified by X-ray fluorescence of bond sulfur before and after the washing process.

Figue 1.24 The fixation (%) yield of reactive dyes (The Chemistry Of Synthetic Dyes, 1996) The above Figure shows in medium shade, up to 30% of the dye is removed by the washing process, while in full shade, up to 50% of the dye is washed away. Considering the reactive dye is highly water soluble, it is quite difficult to separate the unfixed dye from the effluent.

It has been found that up to 50% of the total cost of a reactive dyeing procedure has to be attributing to the wash off and after treatment of the effluent. This limitation can be recognised as the main aspect of

preventing reactive dyes from dominating the dye-stuff for cellulosic materials (Rattee and Breuer, 1994). At the end of printing, when the cotton is washed and rinsed to remove colorant and auxiliaries, an average of 70-150L of water is required for dyeing 1 kg of cotton with reactive dye (Schneider, 2004).

Reactive dyeing effluents contain high concentrations of salt, hydrolysed reactive dye from incomplete fixation, heavy metals and a variety of dyeing auxiliaries, contributing to high BOD/COD values (Moulin et al.

2006). As seen in Fig 1.25. In addition, these effluents shows a pH of

10-11 and a high temperature (50-70ºC).

Figure 1.23 Reactive dyeing effluents emission (http://news.cnhubei.com/xw/gn/201302/t2464886.shtml) The large amounts of organic compounds breakdown in water can remove all the oxygen out of rivers, resulting in killing fish and turning the clear water into a sewer. Obviously, a proper treatment of the effluents (Fig 1.26) is necessary and thus, adds cost. To make matters worse, not everybody takes this step voluntarily.

Figure 1.24 Treatment of the effluents (http://www.thermaxindia.com) According to an article of ―THE WALL STREET JOURNAL‖, authorities discovered a pipe buried underneath a dyehouse floor in China that was dumping roughly 22,000 tons of water contaminated from its dyeing operations each day into a nearby river". Fountain Set was heavily fined and forced to upgrade its treatment system (Jane Spencer, 2007).

Such connection is fortunately not common but may put brands at jeopardy as well as deteriorating the environment significantly.

One third of the world population is lacking clean water, but the times of immoderate water usage by the textile industry seem to be ending, mainly because the price of water is higher by the day and environmental regulation is stricter in most countries. The other reason is that in most areas where the textile industry is established, there is not enough clean water to use.

The textile industry, particularly the cellulose dyeing industry is major contributor to water pollution and primary consumers of water in the world. Millions of tons of water are consumed and contaminated with dyes, salt, heavy metals and toxic substances of all kinds. Most of that 42

water is sent back to the environment without adequate treatment and is harmful to the fauna and flora of rivers. Reducing the water consumption and effluent load is not only related to the factory profit-making, but also related to the environmental sustainability. How to get colour into cellulosic materials with less water is the biggest issue the textile industry is facing today. In the medium term, the textile industry has to keep working on methods to use less water. From section 1.1.2.2, reduce the water consumption of wash off process is a priority for all.

1.1.4 Phosphonic acid reactive dye

In 1973, researchers at the Stanford Research Institute discovered that phosphonic acid derivatives could be induced to react with alcohols to give phosphonate monoesters under certain circumstances. Industries developed a new type of reactive dye based on the research of Stanford

Research Institute. This dye contained phosphonic (PO (OH)2) or phosphoric (OPO(OH)2) acid reactive groups attached to the dye chromophore. In 1977, ICI launched a range of reactive dyes (Procion T dyes) for cellulosic fibres that were based on these researches. This kind of dye had very low substantivities and was applied by the pad-dry thermosol method at temperatures of 210-220ºC under mildly acidic conditions (pH 5-6). These dyes generated the free phosphonic acid form under thermofixation conditions (Fig 1.27).

Figure 1.25 Phosphonic acid derivative react with cellulose (Cellulose Reactive Dyes: Recent Development and Trends, 1990) Structures of many of Procion T dyes were based on the versatile intermediate 3-aminophenylphosphonic acid attached to typical monoazo chromogens in various ways (Renfrew and Taylor, 1990).

Figure 1.26 Synthesis of Procion T dyes (Cellulose Reactive Dyes: Recent Development and Trends, 1990) An important feature of this kind of dye-fibre bond system was the necessity to use an auxiliary for the bond formation, such as cyanamide or dicyandiamide, as seen in Fig 1.29 and Fig 1.30.

Figure 1.29 Cyanamide

Figure 1.30 Dicyandiamide The fixation mechanism can be demonstrated in terms of cellulose attack at an iso-urea (Fig 1.31) or a phosphonic acid anhydride intermediate (Fig

1.32).

Figure 1.27 Iso-urea

Figure 1.32 Phosphonic acid anhydride Through early studying, formation of the phosphonic anhydride was assured to precede the esterification step (Amato et al. 1987). As shown below.

Figure 1.33 Formation of the phosphonic anhydride (riazinylamino-alkylphosphonate reactive dyes for cellulosic fibres, 2007) An alternative mechanism enables dye phosphonate to react with cyanamide (or dicyandiamide) to generate a cationic adduct (Fig 1.34).

Such derivative readily reacts with the cellulose fibre to form a covalent bond.

Figure 1.28 Cationic adduct generated by dye phosphonate and react with cotton (riazinylamino-alkylphosphonate reactive dyes for cellulosic fibres, 2007) Typical dyes of this kind are the monophosphonic acid 1 and the diphosphonic acid derivative 2, in which the phosphonic acid moiety is attached directly to the aromatic ring of a diazo component, as shown in

Fig 1.35 and Fig 1.36.

Figure 1.29 Monophosphonic acid 1 (New Phosphonic Acid Reactive Dyes for Cotton, 1987)

Figure 1.30 Diphosphonic acid derivative 2 (New Phosphonic Acid Reactive Dyes for Cotton, 1987)

1.1.5 Reactive dyes in inkjet printing

As described in section 1.1.2.3, this high chroma, water-soluble colorants form a covalent bond with cellulosic fibre to produce a bright durable colour print with excellent wash fastness.

The general process route of cotton inkjet printing is to pad the necessary auxiliaries on the fabric before the inkjet printing stage. This is because the auxiliary chemicals required, such as urea, alkali, cannot generally be incorporated into the inks (Tincher et al. 1996). Details were mentioned in section 1.1.2.2.

Then the jet nozzle would eject the designed pattern on the desired area.

Cotton inkjet printing always requires a fixation stage (heat or steam), together with washing off the unfixed dye and excess chemicals. Fig 1.37 demonstrates the fixation mechanism. Due to the physical and chemical

specification of jet ink formulation (e.g. ink stability, etc.), the mono chlorotriazine reactive dye is generally used in cotton inkjet printing.

Figure 1.31 Fixation to cellulose and hydrolysis of the dye (Cellulosic Dyeing, 1995) As discussed section 1.1.2.2, commercial inkjet inks based on reactive dye normally have low-to-moderate fixation properties. Hence it is important to maximize dye fixation for technical, economic and environment reasons.

1.2 Research purposes

Based on the literature review, generally speaking, the reactive dyes used in printing often have an unsatisfactory degree of fixation. And in order to achieve the high level of wash fastness, removal of the unfixed dye thoroughly is necessary. In this case, expensive washing off process has a serious environmental impact due to the large amounts of water and the effluent containing hazard chemicals.

A high dye fixation (closer to 100%) of reactive dye would be a great achievement for human beings and environment. The chemical modification of reactive dye in order to improve their dyeability is a

viable route. Introducing new reactive groups to a reactive dye that may be attracted by the anionic charges on cellulosic fibre, and as result a high degree of dye-fibre fixation, a reduced washing off process and excellent wash fastness.

The aim of this research was to investigate the possibility of improving the fixation efficiency of a reactive dye to cellulosic fibre in inkjet printing applications through employing reactive dyes containing phosphonic group, in the presence of a catalyst:cyanamide and dicyandiamide (B. L. Mcconnell et al, 1979)

In this research, three different modified dyes was designed and synthesised by the reaction of a commercial Dichlorotriazine reactive dye with a suitable phosphonic acid. It is proposed that these dyes may be fixed by dry heat, and may result in levels of fixation sufficiently high to negate the need for washing procedures. In the following steps, the application of the synthesised dye to cotton fabric was firstly carried out by a pad-batch-dry-bake method in university laboratory. Catalyst type and concentration were optimised to give the maximum colour yield and maximum fixation. Then investigated the use of synthesised phosphonic acid reactive dyes for application to cellulosic substrates via inkjet printing was continued. Effects of dye application on dye fixation and strength retention of cotton substrate were assessed through scientific instruments. All of those tasks were done by the author himself.

2. Research Methodology

The following up aim of this work was to formulate a reactive dye-based ink containing the modified dye in the previous step, with the further intension of producing a reactive inkjet print on cotton fabric. Three phoshonic containing dyes were synthesised in this section.

Experimental Materials:

The fabric used in this study was scoured and bleached plain weave 100% cotton.

The cotton fabric was cut in size 20cm * 20cm.

Dyestuffs:

A highly reactive dye (dichlorotriazine) was selected and used in the study. It was applied and manufactured by Kemtex, UK, under the commercial name Procion blue MX-2G (C.Z Reactive Blue 109).

Auxiliaries:

The following auxiliaries and chemicals were used either for pad-bake method or for the inkjet printing on cotton.

2.1 Convert commercial dye (MX-2G Blue) to phosphonic acid containing dye

2.1.1 Synthesis of Dye 1

In this process, commercial reactive dye MX-2G blue was modified by chemical reactions and converted to phosphonic acid dye 1.

Experimental Materials:

Molecular sieves, 1, 4-dioxane, Phosphorus trichloride,

N-(hydroxymethyl)acetamide, Hydrochloric acid, distilled water.

N.B. Chemicals used in this research are laboratory-grade standard, and supplied either by Sigma Aldrich or by BASF.

A highly reactive dye (dichlorotriazine) was selected and used in the study. It was applied and manufactured by Kemtex, UK, under the commercial name Procion blue MX-2G.

Equipment and instrumentation:

Fume Hood, Balance (electronic), Beakers, Pipettes, Spatula, Stirring rods, , Weight boat, Paper towels, dropping funnel, thermometer with quick-fit adapter, a 3-neck 250ml round-bottom flask, oil bath, hotplate, laboratory jack, overhead-stirrer, iron stand, desiccator & vacuum pump,

100ml single neck round bottom flask, magnetic stirrer, reflux condenser,

Rotary Evaporation.

2.1.1.1 Synthetic intermediate process

In this step, an intermediate used in modify MX-2G was synthesised. As shown in the figure below.

Figure 2. 1 Intermediate synthesised Molecular sieves are crystalline aluminosilicates, which have a three dimensional inter-connecting network. Precise and uniform pores are spread over the surface. These pores are small enough to allow small molecules to pass while larger molecules are not allowed. In other words, the small molecules are adsorbed. As an example, a water molecule is small enough to pass through the pores, so the water is retained within the pores. Molecular sieves are often used as adsorbent for liquids, as a single molecular sieve can adsorb water up to 22% of its own weight without changing the solution composition (Mineral Adsorbents, 2014)

In this case, the water content of the 1, 4-dioxane solution needs to be reduced to very low values. Molecular sieves were used to remove water inside the solution.

Molecular sieves need to be dried in oven for 48 hrs before applying to 1,

4-dioxane solution. Evenly placed 50g of molecular sieves in a round glass pane, laid the pane in oven at 80ºC for 48 hrs. Once the drying procedure was complete, added the dried molecular sieves into 100ml of 52

1, 4-dioxane solution. This mixture should be operated in a bottle. As long as the operation was complete, closed the lid and standed for 2 days.

Prepare:water bath at 20ºC , dropping funnel, thermometer with quick-fit adapter, a 3-neck q00ml round-bottom flask, oil bath, hotplate, laboratory jack, overhead-stirrer, iron stand

Weighted 2.7 g of distilled water in a 50ml beaker and set aside.

Weighted 15.26g of phosphorus trichloride and placed in round bottom flask, then mixed with 15ml of dried 1, 4-dioxane. Placed the mixture in

20ºC water bath on the raised laboratory jack, clamping on the stand ensure the flask will stay up when the water bath is removed. Following insert the thermometer, overhead stirrer and dropping funnel.

Weighed 9.18g of N-(hydroxymethyl)acetamide in a beaker and dissolved in 5ml 1,4-dixoane.

The solution was transferred to the closed dropping funnel. 5ml of 1,

4-dioxane was added to rinse the beaker, and added to the dropping funnel as well.

Started the stirring of the mixed solution, make sure the temperature of the mixture is about 20ºC at the same time.

Gently opened the tap of the dropping funnel and added the

N-(hydroxymethyl)acetamide solution slowly to the phosphorus trichloride and 1,4-dioxane mixture. Stopped the add process when the temperature climbed over 25ºC .

After added the entire N-(hydroxymethyl)acetamide solution, closed the dropping funnel and transferred 2.7g of water to the closed funnel. Added the water to the lower solution very slowly. After that, added 3 ml of 1,

4-dioxaneto the dropping funnel, rinsed the funnel and added quickly to the solution on the laboratory jack.

Replaced the water bath with the hotplate. Started heating the solution to

100ºC as soon as possible. Kept an eye on the stirring status. Make sure it worked well.

Kept the temperature at 100ºC by modifying the settings on the hotplate, the reaction mixture was stirred at 100 ºC for 5 hours.

Then left the mixture at room temperature to cool overnight.

The following day, decanted the upper layer carefully and disposed in waste solvent bottle with the help of a separating funnel.

Added 30ml of water to the retained solution. Shaked well and located the solution to a distillation flask.

Fitted the flask to a rotary evaporator and evaporated the water under reduced air pressure at roughly 60ºC .

Once the precipitate can been observed and deposited on the sides of the flask, collected the precipitate and dried in a desiccator to constant weight.

Vacuumed the desiccator before placed the precipitate and sealed well after the transference.

Prepare oil bath, 100ml single neck round bottom flask, hotplate, magnetic stirrer, reflux condenser.

Dissolved the dried product in last step in 50ml of 10% hydrochloric acid solution.

Deposited the flask on hotplate and connected to the reflux condenser, heated up to the boil and refluxed for 5 hrs.

Cooled the solution in room temperature and neutralised the pH.

Figure 2. 2 Phosphorus trichloride

Figure 2. 3 N-(Hydroxymethyl)acetamide

2.1.1.2 Convert commercial dye to phosphonic acid containing dye 1

A commercial dye of Procion MX-2G Blue (Fig 2.4), which was assumed to be 50% pure (equal parts of dye and colourless diluents), was reacted with intermediate product synthesised in last step to form a dye containing two phosphonic acid groups (Fig 2.5).

Commercially formulated reactive dye commonly contains in the region of approximately equal parts of dye. Portion of non-reactive dye (i.e. impure component generated during commercial formulation,

decomposition of the dye by hydrolysis during the storage) presence in the amount of dyestuff is very common (K Venkataraman, 2012).

Previous investigations (Alexandre Paprocki et al, 2010) on purity of commercial dye from two suppliers prove this phenomenon: Acros

(purity 63.2%) and Sigma (> 80%). In this case, the HPLC cannot give a clear test outcome on the original dye (MX-2G) and the accurate purity cannot obtain. From the experimental results performed by other workers,

Procion MX-2G Blue was assumed to be 50% pure to implement the complete reaction between original and intermediate.

Figure 2. 4 MX-2G Blue dye structure

Figure 2. 5 Phosphonic acid containing dye 1

9.37g of the Procion MX-2G (0.0009 mol) was added to a stirred solution of the intermediate (0.1998g, 0.0018 mol dissolved in distilled water,

500ml beaker).

Raised the temperature of the solution to 35ºC and left to stir at this temperature for 1 hour.

Increased the temperature to 90ºC , this condition was maintained, with stirring, for another 1 hour.

The reaction mixture was cooled to room temperature and added concentrated hydrochloric acid until pH 1.

The blue dye precipitate was then filtered by a Buchner apparatus.

The dye was finally dried in a desiccator.

2.1.2 Synthesis of Dye 2

In this process, commercial reactive dye MX-2G blue was modified by chemical reactions and converted to phosphonic acid dye 2.

Experimental Materials:

Dimethylolurea, Crystalline phosphorous acid, Hydrochloric acid, distilled water.

N.B. Chemicals used in this research are laboratory-grade standard, and supplied either by Sigma Aldrich or by BASF.

A highly reactive dye (dichlorotriazine) was selected and used in the study. It was applied and manufactured by Kemtex, UK, under the commercial name Procion blue MX-2G.

Equipment and instrumentation:

100ml single neck round bottom flask, magnetic stirrer, reflux condenser,

Rotary Evaporation.

2.1.2.1 Synthetic intermediate process

In this step, an intermediate used in modifying commercial dye (MX-2G) was synthesised: bis(aminomethylphosphonate), see Fig 2.6.

Figure 2.6 bis(aminomethylphosphonate) Dispersed 1.9g of dimethylolurea in 50 ml of distilled water (100 ml

2-necked round-bottom flask).

Added 2.0g of phosphorous acid.

Slowly dropped in 3.9g of hydrochloric acid.

Placed the flask in an oil bath, fitted with condenser, thermometer and dropping funnel, then heated to reflux.

Left to reflux for an additional hour.

Decanted the solution into a rotavap flask.

Evaporated some of the water with the rotavp until the solution is concentrated.

Added ammonia solution to reach pH 7.

Added methanol to the solution until precipitation occurs.

2.1.2.2 Convert commercial dye (MX-2G Blue) to phosphonic acid containing dye 2

The bis(aminomethylphosphonate) synthesised in last step was added to the dye solution (MX-2G Blue) in a 500ml beaker.

Increased the temperature to 35ºC and left to stir at this temperature for 1 hour.

Then increased the temperature to 90ºC and left to stir at this temperature for another 1 hour.

Left the solution to cool then added hydrochloric acid until pH 1.

Filtered the dye precipitate using a Buchner apparatus.

Placed the filtrate in a desiccator to dry.

Figure 2.7 Phosphonic acid containing dye 2 59

In the following padding process, the synthesised Dye 2 had extremely low dye fixation efficiency on cellulosic substrate. After wash off procedure, approximately 90% of dye 2 was washed away. Thus the application of dye 2 on cotton via inkjet printing and the follow-up tests did not carry on.

2.1.3 Synthesis of Dye 3

In this process, commercial reactive dye MX-2G blue was modified by chemical reactions and converted to phosphonic acid dye 3.

Experimental Materials:

H-acid, Crystalline phosphorous acid, Hydrochloric acid, distilled water.

N.B. Chemicals used in this research are laboratory-grade standard, and supplied either by Sigma Aldrich or by BASF.

A highly reactive dye (dichlorotriazine) was selected and used in the study. It was applied and manufactured by Kemtex, UK, under the commercial name Procion blue MX-2G.

Equipment and instrumentation:

100ml single neck round bottom flask, magnetic stirrer, reflux condenser,

Rotary Evaporation.

5.0g of H-acid (4-Amino-5-hydroxy-2, 7-naphthalenedisulfonic) was dispersed in 50 ml f water in a 100 ml 3-necked round-bottom flask.

Added 1.0g of phosphorous acid.

Slowly dropped in 1.8g of hydrochloric acid.

Placed the flask in an oil bath, fitted with condenser, thermometer and dropping funnel, then heated to reflux.

Placed 1.0g of formaldehyde solution in the dropping funnel.

Slowly dropped the formaldehyde solution to the refluxing H-acid solution.

Tested for the presence of unreacted H-acid with Ehrlich reagent at intervals. N.B. Ehrlich reagent will turn orange in the presence of free aromatic amine.

Left to reflux for an additional hour.

Decanted the solution into a rotavap flask. In this step, the refluxing solution turned into thick, black goop and no longer able to decant into a rotavap. A repeat experiment was carried out again in the same condition, and the same unknown substance (thick & black goop) was arising in the round-bottom flask.

Since this, the synthesis method was not able to modify the commercial dye (MX-2G Blue) in practice.

2.2 Application of modified dye to cotton

2.2.1 Pad-batch method 61

In section 2.1, as the synthesised dye 2 & 3 was not suitable for cellulose dyeing and printing, the synthesised dye 1 was used in the follow-up process. In later sections, the modified dye and the phosphonic containing dye only reference to the synthesised dye 1(Fig 2.5).

To investigate the effect of cyanamide and dicyandiamide concentration on the padding procedure, the pad liquors were prepared with varying concentrations of catalyst.

Experimental Materials:

The fabric used in this study was scoured and bleached plain weave 100% cotton. The cotton fabric was cut in size 20cm * 20cm.

Dyestuffs:

Modified dye synthesised in section 2.1.1.

Auxiliaries:

The following auxiliaries and chemicals were used either for pad-bake method or for the inkjet printing on cotton (Gillingham et al, 2007).

Ammonium dihydrogen phosphonate, supplied as a dry crystalline powder.

Cyanamide was supplied as a 50% aqueous solution.

Dicyandiamide was supplied as a dry crystalline powder. According to specification of dicyandiamide from Sigma-Aldrich, the solubility can be

50 g/L. Actually the solubility is lower than the specification at room temperature.

N.B. Chemicals used in this research are laboratory-grade standard, and supplied either by Sigma Aldrich or by BASF.

Equipment and instrumentation:

Fume Hood, Balance (electronic), Beakers, Pipettes, Spatula, Stirring rods, Weight boat, Paper towels, Matthis Laboratory pad mangle, Mathis forceddraft oven, volume flask, polythene, Anion detergent, hot plate.

2.2.1.1 Pad liquor preparation

Pad liquors were prepared containing the phosphonic acid containing dye (10 g dm-3), ammonium dihydrogen phosphate (10 g dm-3) and catalyst (0, 30, 60, 90, 120 and 150 g dm-3).

Stock solutions of dye and ammonium dihydrogen phosphate were made up by dissolving 3.125g dye and ammonium dihydrogen phosphonate powder in distilled water.

Cyanamide stock solution was used directly from 50% aqueous solution.

In actual practice 50% concentration for dicyandiamide solution cannot achieved in room temperature. Dicyandiamide is unlikely to completely dissolve in water at concentration in excess of 40 g/L. However its solubility increases with increase in the water temperature quickly.

Pre-heated distilled water to 35ºC , and then the warm water was used to dissolve dicyandiamide powder to obtain 50 g/L stock solution.

The concentration of catalyst was varied (0, 30, 60, 90, 120 and 150 g dm-3 of cyanamide and dicyandiamide) to give a series of pad liquors.

Each pad liquor (25ml) containing 4 ml dye stock solution, 4 ml ammonium dihydrogen phosphonate stock solution, X ml catalyst

(cyanamide or dicyandiamide), required amount of distilled water to fill up to 25 ml. Symbol X on behalf of the cyanamide or dicyandiamide volume used in different catalyst concentration. Table below show the X variation in each pad liquor.

Cyanamide (X) Dye Ammonium dihydrogen phosphonate

Pad liquor 0 0ml 4ml 4ml

Pad liquor 1 1.5ml 4ml 4ml

Pad liquor 2 3ml 4ml 4ml

Pad liquor 3 4.5ml 4ml 4ml

Pad liquor 4 6ml 4ml 4ml

Pad liquor 5 7.5ml 4ml 4ml

Table 2.1Pad liquor pepartion (Cyanamide)

Dicyandiamide (X) Dye Ammonium dihydrogen phosphonate

Pad liquor 0 0ml 4ml 4ml

Pad liquor 1" 1.5ml 4ml 4ml

Pad liquor 2" 3ml 4ml 4ml

Pad liquor 3" 4.5ml 4ml 4ml

Pad liquor 4" 6ml 4ml 4ml

Pad liquor 5" 7.5ml 4ml 4ml

Table 2.2 Pad liquor pepartion (Dicyandiamide) 64

2.2.2.2 Pad/Pad (batch)-bake process

Prepared 11 clean volume flasks (25ml), labeled them from Pad liquor 0 to Pad liquor 5". Added corresponding regents into the volume flask as illustrated in table 2.1 and Table 2.2.

After adding the reagents, each pad liquor adjusted pH to 5-5.5 with small amounts of aqueous ammonia. Then added distilled water to fill up to

25ml. Shaked well prior to applying pad liquor to cotton fabric.

The padding process was carried out on a Matthis Laboratory pad mangle, with nip-pressure set to obtain approximately 74% wet pick-up.

Deeply cleaned the padding mangle before applying pad liquor to cotton.

Turned on the pad mangle and set air pressure at 4 bars with rotational velocity set at 1.6 r/min.

Decanted one pad liquor into padding trough, fed one piece of prepared cotton fabric in to squeeze roll. The uniform expression of the pad liquor was achieved by passing the cotton fabric through the arranged rolls, as cotton emerged from the trough.

The freshly padded fabric was cut into two; one half of each piece was wrapped in polythene immediately to avoid any air exposure and then batched at room temperature for 24 hours. The other half just dried on frames.

The following day, both fabrics were mounted on pin frames and pre-dried at 100ºC in a Mathis forceddraft oven for 2 min.

Then samples were baked at 185ºC for 90 secs.

N.B. According to the reference experiment (Estelle L Gillingham &

David M Lewis, 2007), the cotton fabrics was baked at 200ºC for 90 secs.

In this research, the sample fabrics were firstly baked at 200ºC for 90 secs.

But the high baking temperatures caused serious fabric yellowing. This will influence the hue of shade. In order to avoid this happening, lower the baking temperature is necessary. Therefore, several attempts were carried out. The sample fabrics were then baked at 195ºC, 190ºC, 185ºC for 90 seconds respectively. The end results indicate that baked a 185ºC for 90 seconds would not affect the hue of shade and would not yellowing the cotton fabric. At that point, baked at 185ºC for 90 seconds is the optimum conition.

The washing off procedure was then carried at boiling aqueous solution

(nonionic detergent: water, 1:50) for 15 min. Later cold rinse was repeated until the rinse water was colourless. Keep the wash up liquors for later measurement.

Air dried fabrics at room temperature for later use

2.2.2 Inkjet printing via modified dye

As described in section 1.1.2.2, unlike the conventional reactive printing on cotton, in inkjet printing process cotton needs to be pre-treated with fixation-enhancing chemicals prior to jet eject ink droplet. In pre-treatment procedure cotton fabrics were padded with pre-treatment

paste. In this case, the pre-treatment paste was prepared with ammonium dihydrogen phosphonate and varying concentrations of catalyst

(cyanamide and dicyandiamide).

Experimental Materials:

The fabric used in this study was scoured and bleached plain weave 100% cotton. The cotton fabric was cut in size 20cm * 20cm.

Dyestuffs:

Modified dye synthesised in section 2.1.1.

Auxiliaries:

The following auxiliaries and chemicals were used either for pad-bake method or for the inkjet printing on cotton (Gillingham et al, 2007).

Ammonium dihydrogen phosphonate, supplied as a dry crystalline powder.

Cyanamide was supplied as a 50% aqueous solution.

Dicyandiamide was supplied as a dry crystalline powder.

Equipment and instrumentation:

Wolke m600 ink-jet printer, HP ink cartridge, syringe equipped with a

0.45 μm cellulose acetate filter.

2.2.2.1 Preparation of pre-treatment paste

The aqueous pre-treatment paste (25ml) was prepared containing the ammonium dihydrogen phosphate (10 g dm-3) and catalyst (0, 30, 60, 90,

120 and 150 g dm-3). The stock solutions were prepared in section 2.2.1.

Each paste containing 4 ml ammonium dihydrogen phosphonate stock solution. Y ml catalyst (cyanamide or dicyandiamide), required amount of distilled water to fill up to 25 ml. Symbol Y on behalf of the cyanamide or dicyandiamide volume used in different catalyst concentration. Table below show the Y variation in each pad liquor.

Cyanamide Ammonium dihydrogen phosphonate (Y)

Pre-treatment paste 0 0ml 4ml

Pre-treatment paste 1 1.5ml 4ml

Pre-treatment paste 2 3ml 4ml

Pre-treatment paste 3 4.5ml 4ml

Pre-treatment paste 4 6ml 4ml

Pre-treatment paste 5 7.5ml 4ml Table 2.3 Pre-treatent paste pepartion (Cyanamide)

Dicyandiamide Ammonium dihydrogen phosphonate (Y)

Pre-treatment paste 0 0ml 4ml

Pre-treatment paste 1" 1.5ml 4ml

Pre-treatment paste 2" 3ml 4ml

Pre-treatment paste 3" 4.5ml 4ml

Pre-treatment paste 4" 6ml 4ml

Pre-treatment paste 5" 7.5ml 4ml

Table 2.4 Pre-treatent paste pepartion (Dicyandiamide)

2.2.2.2 Pre-treatment and Inkjet printing process

Prepared 11 clean volume flasks (25ml), labeled them from Pre-treatment paste 0 to Pre-treatment paste 5". Added corresponding regents into the volume flask as illustrated in Table 2.3 and Table 2.4.

2.2.2.2.1 Pre-treat sample fabrics

The padding process was carried out on a Matthis Laboratory pad mangle, with nip-pressure set to obtain approximately 74% wet pick-up. And a constant padding speed of 1.6 r/min.

Decanted one pre-treatment paste into padding trough, fed one piece of prepared cotton fabric in to squeeze roll. The uniform expression of the paste was achieved by passing the cotton fabric through the arranged rolls, as cotton emerged from the trough.

Air dried the padded fabrics at room temperature and then conditioned before inkjet printing.

2.2.2.2.2 Inkjet printing process

The ink-jet printing was carried out on a Wolke m600 ink-jet printer.

Ink preparation

Reactive dye synthesised in section 2.1 was used in this case. The concentration of dye solution was 10g dm-3. Dissolved 2.5g dye in 50ml distilled water and stirred evenly. The prepared ink was filtered through a syringe equipped with a 0.45 μm cellulose acetate filter of 25 mm diameter to prevent clogging the jet nozzle before filling into the cartridge. Before filling dye solution, the ink cartridge was deeply cleaned, filled with distilled water. After that put the cartridge back to printer and printed on a blank cotton fabric until no more colour shade come out of the ink cartridge. In this way, the jet nozzle was flushed thoroughly so that the ink used in the later would not be affected by the previous content. After that was complete, emptied out the water inside of the cartridge and kept upside down for a day to flush off remaining water.

Then filled the filtered dye solution into ink cartridge slowly, sealed filler hole well.

Mounted ink cartridge onto the printer. A piece of cotton substrate was clipped together with printer bed.

Turned on printer and selected Label→PR→Load on the screen of printer.

When the indicator light turns green, which means it is ready to print.

Grabbed the holder of printer and moved toward the left hand direction

until the printing plate passed the sensor, which was located on the printer bed.

After that, returned the printing bed to the original position. One printing pass has been done.

Once a certain area had been printed, shifted the sample fabric to an unprinted area.

Followed the process described above to print the rest pre-treated fabrics.

Printed fabrics were mounted on pin frames and pre-dried at 100ºC in a

Mathis forceddraft oven for 2 min.

Then samples were baked at 185ºC for 90 secs.

The washing off procedure was then carried at boiling aqueous solution

(nonionic detergent: water, 1:50) for 15 min. Later cold rinse was repeated until the rinse water was colourless.

Dried in the air.

For comparing and analyzing the influence of catalyst on cotton fabric, an unpretreated reference cellulose fabric was printed via inkjet printing as described above. After printing, dried in the air and carried out the wash off process.

2.3 Inkjet printing via Desktop inkjet printer

In order to assess effects of dye application on strength retention of cotton substrate, the dye modified in section 2.1.1 was applied on cotton fabric through desktop inkjet printer. Then the printed samples were tested on

Instron Tensile Strength instrument. Compared the results with blank cotton fabric, the influence of dye applied would be obtained.

Experimental Materials:

The fabric used in this study was scoured and bleached plain weave 100% cotton. In order to fit the fabrics in the printer, the size of cotton samples is same as A4 paper. Cut 5 pieces of A4 size cotton samples from the cotton roll.

Dyestuffs:

Modified dye synthesised in section 2.1.1.

Auxiliaries:

The following auxiliaries and chemicals were used either for pad-bake method or for the inkjet printing on cotton (Gillingham et al, 2007).

Ammonium dihydrogen phosphonate, supplied as a dry crystalline powder.

Cyanamide was supplied as a 50% aqueous solution.

Dicyandiamide was supplied as a dry crystalline powder.

Equipment and instrumentation:

Deskjet 840c printer, 3M adhesive, HP ink cartridge, syringe equipped with a 0.45 μm cellulose acetate filter.

2.3.1 Pre-treatment of cotton fabrics

The aqueous pre-treatment paste (25ml) was prepared containing the ammonium dihydrogen phosphate (10 g dm-3) and catalyst (150 g dm-3).

The stock solutions were prepared in section 2.2.1.

Each paste containing 4 ml ammonium dihydrogen phosphonate stock solution. 7.5 ml catalyst (cyanamide or dicyandiamide), required amount of distilled water to fill up to 25 ml. Table below show the component in each pad liquor.

Cyanamide Dicyandiamide Ammonium dihydrogen phosphonate

Pre-treatment paste 7.5ml 0ml 4ml Cyanamide

Pre-treatment paste 0ml 7.5ml 4ml Dicyandiamide Table 2.5 Pad liquor component Prepared 2 clean volume flasks (25ml), labeled them from Pre-treatment paste Cyanamide and Pre-treatment paste Dicyandiamide. Added corresponding regents into the volume flask as illustrated in Table 2.5.

After adding the reagents, each pad liquor adjusted pH to 5-5.5 with small amounts of aqueous ammonia. Then the paste was made up to a volume of 25ml with distilled water. Subsequently mixed thoroughly prior to applying pre-treatment paste to cotton fabric. The padding process was carried out on a Matthis Laboratory pad mangle, with nip-pressure set to obtain approximately 74% wet pick-up. And a constant padding speed of

1.6 r/min. As described in section 2.3.2. 73

Air dried the padded fabrics at room temperature and then conditioned before inkjet printing.

For the purpose of study how the catalyst would affect fabric tear strength, an unpre-treated cotton sample would be printed via desktop inkjet printer as a control.

2.3.2 Desktop inkjet printing process

Before printing on fabrics, an important ancillary step is necessary.

Because the cotton fabrics cut from the beam were too soft to feed into desktop printer, it is necessary to stick fabric to a firm paperboard. The following step in necessary to achieve this aim.

Sprayed adhesive onto a piece of A4 size firm paperboard uniformly.

Sticked one piece of cotton fabric to the paperboard with caution, make sure the sample fabric dose not wrinkle up when it is stretched during this process.

Applied even pressure over the entire sample fabric through hands, ensure the firm binding of fabric and paperboard.

Dried in the air.

In this case, 3 bonded sample fabrics were prepared: Cyanamide and

Dicyandiamide pretreated cotton fabrics and one unpre-treated sample fabric.

2.3.2.1 Desktop inkjet printing:

Used the same ink cartridge in section 2.3, mounted it onto the desktop inkjet printer. Connected printed and computer.

Opened Microsoft Word, set the background of writing board as black.

Fed one of the three bonded print substrate into paper feed channel, make sure the cotton fabric side would be printed later.

Clicked File-print, on the print setting board, ticked print background, then clicked print.

Air dried the printed fabric.

Printed the rest two samples as mentioned above.

Peeled the cotton fabric from the paperboard carefully.

Placed these printed fabrics on the table, allowed them to dry completely.

2.3.2.2 Dye fixation (bake) process

In this step, a piece of white (unprinted) sample fabric was baked as the others in order to achieve comparison data afterwards.

Printed fabrics were mounted on pin frames and pre-dried at 100ºC in a

Mathis forceddraft oven for 2 min.

Then samples were baked at 185ºC for 90 secs.

The washing off procedure was then carried at boiling aqueous solution

(nonionic detergent: water, 1:50) for 15 min. Later cold rinse was repeated until the rinse water was colourless.

Dried in the air for subsequent requests.

3 Evaluate modified dye performance

3.1 Colour strength measurement for inkjet printed sample fabrics via spectrophotometer

CIE L*a*b* colour space supports the accepted theory of colour perception based on three separate colour receptors, RGB (Red, Green, and Blue), in the eye. When reflected light reaches these receptors, they are excited. This results in three sets of signals being sent to the brain: light or dark, red or green, and yellow or blue (Hunt, 1987). As shown below.

Figure3. 1 CIE L*a*b* (http://dba.med.sc.edu/price/irf/Adobe_tg/models/cielab.html) L* is a measure of the lightness of an object and ranges from 0 (black) to

100 (white). a* is a measure of redness (positive) or greenness (negative). b* is a measure of yellowness (positive) or blueness (negative).

A spectrophotometer compares the amount of light that is shined onto an object with the amount of light that is reflected back from that object. It analyzes light energy reflected or transmitted by a sample, wavelength by

wavelength.

Figure3.2 Spectrophotometer Datacolor 650 From the spectral energy distribution of one or more illuminants (e.g. A,

C, D65), tristimulus responses of standard observes (2°or 10°) and the spectral graph of the sample, spectrophotometer calculates the tristimulus value for any illuminant and one observer. It is simple and rapid to use.

In this case, the Datacolor 650 spectrophotometer was used to measure the L* (lightness) of inkjet printed fabrics in section 2.3. The software used in this measurement is datacolor TOOLS, Version 2.0.1.

3.1.1 Measure samples

Opened software on computer, applied the following options for the settings:

Specular：Exclude

Aperture: Small

UV-Filer: 100% UV (Filter off).

Calibrated the spectrophotometer then.

After calibration, folded one sample twice until no light can go through sample.

N.B. one sample consists of two areas: printed and unprinted area, make sure fold the wanted area outside. In this operation, always measure the unprinted area firstly.

Attached folded sample to presentation port, clicked confirm label on the control interface to measure L*.

Shifted sample to another location and measured again.

Measured four different locaions, and the processor would give an average value for each measured area.

Afterwards, measured the printed area by the same steps.

After finishing all the measurement, printed the value form. N.B. form titled with 0.1 stands for unprinted area, 0.2 stands for printed area.

N.B. the L* is measured under CIE Standard Illuminant D65. The measurement data is attached in appendix.

3.2 Tensile Test

Tensile test tests a material's strength. It is a mechanical test where a pulling force is applied to a material from both sides, until the sample breaks, which is commonly used to determine the maximum force that a material can withstand. Thus curve of tensile profile showing how

material will react to pulling force being applied can be obtained. By measuring changes, a variety of information including yield point (the amount of tension that causes the sample to break), tensile strength and ultimate strength (the maximum tensile force that the sample can stand) of the material can be determined, which is helpful in deciding whether it is a suitable choice for the certain application.

Figure3.3 Instron Force Transducer The result of this test is a curve of force (amount of weight) versus displacement (amount it stretched).

The basic theory of a tensile test is to place a sample of a material between two grips, which clamp the sample material. Then begin to apply

pulling force to the material gripped at one grip as the other grip is fixed.

Keep increasing the force while at the same time measuring the change in length of the sample.

Tensile test is very important in numerous industries, especially in textile industry. For example, during the planning stage of a garment, for stable construction and durable purpose, select appropriate material which will able to withstand certain stresses and abrasion without breaking.

3.2.1 Tensile Procedure

In order to investigate the influence of temperature on cotton fabric strength, an unpre-treated and unbaked cotton fabric was tested as a reference. As described in section 2.4, 5 pieces of sample fabrics were carried out through tensile test.

Pretreated Printed baked Wash off

sample 1 Cyanamide √ √ √

sample 2 Dicyandiamide √ √ √

sample 3 / √ √ √

sample 4 / √ √

sample 5 / √ Table 3.1Samples preparation. In principle, there were two sets of test specimen (quantity 2 per set): one in the warp direction and the other in the weft direction of the cotton fabric.

Cut 4 specimens 50mm wide and 200mm long. Removed an equal number of yarns from each side in order to obtain a 50mm width. N.B: take utmost care in cutting specimen to prevent tears along the edges of the fabric.

Placed the one piece of specimens in the grips of the testing machine, make sure the specimen aligned with the direction of pull perfectly.

The test machine is then controlled by computer software. The software steadily increased the force exerted on the specimen, along with displacement, until the specimen failed.

The testing software automatically calculated results and statistics, and finally produced a test report including the recorded force-elongation curve.

Removed the failed specimen from the machine and fitted the new specimen. Repeated the steps as above.

In the end, collected all the reports of specimen for later analysis.

3.3 Ultraviolet-Visible spectrophotometry

UV-visible spectrophotometry is one of the most important techniques in chemical analysis. By measuring the amount of ultraviolet or visible light and the wavelength that a compound absorbs, the molecular structure and the concentration can be determined (Behera et al. 2012). See Fig 3.4.

Figure3. 4 UV-Spectrophotometer (UV-VIS Spectroscopy - Chemical Analysis, 2009) The fundamental law used in spectrophotometry is the Beer-Lambert law, shown as below:

Figure3. 5 Beer-Lambert law (UV-VIS Spectroscopy - Chemical Analysis, 2009) In this search, the solutions in section 2.2 were measured their absorbance at suitable wavelength. Generally the wavelength selected is at the maximum absorption.

3.3.1 Sample measurement

A Camspec M550 Spectrophotometer with matched cuvettes was used in this research.

In section 2.2, the wash off solutions were kept and measured in this stage. Three samples were collected from each wash off solution, and measured separately. Then the average value was calculated and recorded.

N.B. only closeness value would be accepted and calculated.

Turned on the Spectrophotometer and allowed at least 15 minutes to warn up.

After the warm up was completed, connected the Spectrophotometer and the software installed in the computer. Then the Spectrophotometer was controlled by the software.

On the file menu, clicked new and selected Wavelength Scan

Measurement and clicked OK

Then clicked D2/W Switch Point, set the lamp switching wavelength position within the range 339 nm to 370 nm.

Clicked icon A from the menu to select absorbance mode.

Afterwards, entered wavelength scan range in the FROM box. In this case, the range from 300nm-700nm. Clicked ok return to the menu. Now the operation conditions for wavelength scanning were set up and ready to collect a spectrum.

Closed the cover of sample compartment. On the UV-Photometer menu, clicked Background on the tool bar. The UV-Photometer would run background correction automatically until the status bar show Ready.

Transferred the wash off solutions to the corresponding cuvettes, and labeled these cuvettes.

Placed sample cuvettes which contain blank solutions in both the reference and sample cuvette holders.

On the UV-Photometer menu, clicked Autozero on the tool bar to zero

the instrument.

Placed a sample cuvette which contains wash off solution in the sample cuvette holder. Closed the cover of the compartment.

Clicked the Operation icon on the tool bar, the instrument would start scanning automatically.

As the scanning going on, the real time spectrum would be displayed on the screen.

Saved the spectrum when the scanning is over.

Measured the rest sample cuvettes as above steps.

The absorbance at the wavelength of maximum absorption (λmax) was measured and recorded.

3.3.2 Standard solution make up

In order to obtain the concentration of the wash off solution in section 2.2, more dye solutions are needed to be measured to create a calibration plot.

A sequence of gradual step-down trend dye solutions (standard solutions) were made up. These solutions were all diluted from the dye stock solution (10 g/L).

The concentrations of these standard solutions are accurately known, and they were all well labeled.

Standard solutions were measured as described above.

The absorbance at the wavelength of maximum absorption (λmax) was obtained and recorded.

3.4 Fourier Transform Infrared Spectroscopy

An FTIR (Fourier Transform Infrared Spectroscopy) technology is used to identify the possible functional groups in chemical compounds. By exciting the molecular rotation and vibration via the absorption of infrared radiation, the interaction of molecules can be identified and measured (Kan, et al. 2000). As known that when chemical compound interacts with infrared radiation, only certain frequencies energy can be absorbed, meanwhile the others are either reflected or transmitted. The frequencies are depending on the functional groups within the chemical compound, and each of groups has the unique frequency. Thus the functional groups are localized by their unique absorption frequencies

(Manfred, et al. 1997). By means of this technology, the chemical composition of substance can be determined.

Figure3.6 Regions of the Infrared Spectrum for analysis (Organic Structural Spectroscopy. 1998). In this research, FTIR was used to determine the likely functional groups

present in commercially reactive dye molecules and modified reactive dye molecules. According to the previous studying (Manfred, et al. 1997), there are two major regions in FTIR spectrum. Absorption bands located in above 1500cm-1 region can be vest in individual functional groups.

Meanwhile the region below 1500cm-1 contains many bands and characterizes the molecule as a whole. It called as the fingerprint region.

Absorption bands arise from functional groups within the fingerprint region can be used to identify groups, but this determination should only consider as an aid to identification, not as a conclusive proof.

In order to interpret the FTIR spectra of the two samples, a reference table of FTIR functional group is necessary to indicate the possible groups within the dyes.

A Camspec M550 FT-IR spectrometer was used to obtain the IR spectrum of the dye sample.

3.4.1 FT-IR measuring procedure

Before measuring the sample dye, the test bench was cleaned deeply so as to eliminating the interference.

FT-IR spectrometer and control computer were well connected.

Opened the Ominc software and chose the option: smart orbit.

Set the testing content as Absorbance.

After that, scanned the background of FT-IR. This step was designed to eliminating the effect of background absorption.

Then placed one of the sample dye on the test bench, make sure the dye powder covered the light hole of test bench.

Scanned the sample twice.

Removed the sample above, cleaned test bench and placed the other sample dye. Scanned the sample twice as well.

The Ominc software generated the sample spectra, at the same time the major peaks were labelled and numbered.

3.5 Thin layer chromatography

Thin layer chromatography (TLC) technique is used to separate mixtures into their individual components. It is used extensively in both the industry and research laboratories because it can be controlled very precisely and uses very small amount of substance.

In TLC, there are two phases in separating the compound—stationary phase and mobile phase. Solvent can be used as eluent in TLC.

According to the chromatography theory, different compounds have different solubility and adsorption in the two phases. In chromatography, a mobile phase (liquid or gas) flows through a stationary phase (often a solid) and carries the components of a mixture with it. Duo the different adsorption rate of different compounds, the migration speed of each compound will be different, and therefore separation of the mixture can be obtained. Different functional groups in mobile phase interact with stationary phase determine the adsorption degree of compounds.

Figure3.7 The separation of a mixture of molecules A&B (http://www.chemguide.co.uk/analysis/chromatography/thinlayer.html) In TLC, the stationary phase (TLC plate) consists of a thin layer of silica gel (or alumina) coated over a piece of solid inert medium (usually aluminium or plastic), and often contains a substance that fluoresces under UV irradiation to facilitate the detection of colourless substances.

In this experiment, the TLC plate consists of a thin plastic sheet covered with a thin layer of silica gel, the structure is shown below.

Figure3.8 A portion of silica gel (http://www.chemguide.co.uk/analysis/chromatography/thinlayer.html) Silica gel consists of a three-dimensional network of thousands of alternating silicon and oxygen bonds, with O-H groups on the outside surface. Hence the silica gel consists of polar functional group. Highly polar molecules will interact strongly with the polar Si-O bonds in silica

gel and thus the high polar molecules will tend to adsorb onto the TLC plate. On the other hand, less polar molecules will tend to travel more rapid than the high polar one.

In this research, TLC is used to determine if two compounds (commercial dye and modified dye) are identical. A spot of the compound being investigated is placed on a chromatography plate, and a spot of a manufactured sample is placed next to it. The plate is then allowed to stand in a suitable solvent, which travels up the plate, seen as Fig 3.9.

Figure3.9 TLC theory If the compound to be identified leaves exactly the same pattern on the chromatography plate as the known compound, it can be conclude that they are the same. Otherwise, they have different compositions.

3.5.1 Producing the chromatogram

A specially designed chamber with a lid,

In this research, solvent were prepared. The compositions solvent is listed below:

Ethyl acetate 5 ml Butanol 10 ml Propanol-1 15 ml Distilled water 20 ml Table 3.2 Solvent component As the polar solvent may change the adsorption of polar molecules, the more polar the solvent, the faster the compound can move over the surface. This will lead to all the mixture travel almost at the same speed.

But, at the same time the separation between non-polar compound and polar compound may not quite distinct. As a result, a mixed solvent which is prepared by mixing high polarity and low polarity solvents would be better to separate compound. In this way the polarity of the solvent can be controlled and any polarity can be created.

Before producing the chromatogram, small and same amount of the commercial dye MX-2G reactive dye and modified dye were dissolved in

Solvent. Added a little bit more of solvent if the dye powder did not fully dissolved.

A pencil line is drawn near the bottom of the plate. Under the line, marked lightly the name (point 1 and point 2) of the sample solutions which would spot on the plate. Left enough space between the samples so that they do not run together.

Obtained a microcapillary, dipped the microcap into one of the prepared dye solution and then gently touched the end of it onto the proper location on the TLC plate. A small drop of the MX-2G dye solution was placed on 90

it. Repeated this step and a small drop of modified dye solution were placed next to point 1, named as point 2. As shown in Fig 3.10.

Figure3.10 TLC Plate ready to be spotted (Thin Layer Chromatography lab. proc. UoM) Poured solvent into the chambers to a depth of just less than 0.5 cm respectively. To aid in the saturation of the TLC chamber with solvent vapors, a piece of filter paper was lined part of the inside of the beaker.

Placed the prepared TLC plate in the chamber, covered the beaker with the lid, and left it undisturbed on the bench top. The solvent would rise up the TLC plate by capillary action. Make sure the solvent does not cover the spot. As seen below.

Figure3.11 TLC plate in solvent (http://www.chemguide.co.uk/analysis/chromatography/thinlayer.html) As the solvent slowly travels up the plate, the different components of the

dye mixture travel at different rates and the mixture is separated into different coloured spots.

The solvent is allowed to rise until it almost reaches the top of the plate.

Marked the position of the solvent front with a pencil before it evaporates.

As seen in Fig 3.12

Figure3.12 Components travelled different distance (http://www.chemguide.co.uk/analysis/chromatography/thinlayer.html)

3.5.2 Rf Values

In addition to qualitative results, Rf Values is used to measure the movement of the components along the plate. The Rf Values (retention factor) is defined as the distance travelled by the analyte divided by the distance travelled by the solvent. As an example, Fig 3.13 explains how to calculate the Rf Values.

Figure3.13 Calculation of Rf value (Thin Layer Chromatography lab. proc. UoM) Comparing the Rf Values with the Rf Values of known compounds might

enable a tentative identification to be indicated. If a solvent has a high polarity, all components in the compound will travel along with the solvent and separation may not be obtained. If the solvent has low polarity the components will not travel enough so that separation may not occur as well.

Since some components may have similar polarities, many of them can have the same Rf Values. Additional determination must be carried out before the final conclusion can be made.

In this research, TLC was used on a microscale to monitor a reaction and determine if the product was successfully synthesised.

4 Results and Discussion

4.1 Dye analysis

The success of the synthetic route to the phosphonic acid containing dye was confirmed by TLC and FT-IR techniques.

4.1.1 Thin layer chromatography

Thin layer chromatography (TLC) test of MX-2G reactive dye and synthesised phosphonic acid containing dye indicates these two dyes are different. As seen in Fig 42, the side-on view of the development of a

TLC plate. As the solvent travels along the plate, equilibrium between the movement solvent and the TLC plate for the dye is established. Simply the silica on the TLC plate tries to bind the dye molecules and the moving solvent tries to dissolve the dye, carrying the dye molecules along as the solvent travels up wards. To put it simply, the process of TLC relies on the question: would the dye prefer to be stuck on the plate or would it prefer to travel along with the solvent?

Since the polarity of the TLC plate is high and is constant at high level, the balance of interactions mainly depends on the polarity of the solvent and the polarity of the compounds applied for separation. If a sample solute consists of two components, one more polar than the other, the more polar will tend to stick more tightly to the plate and the less polar will tend to move along more freely with the solvent. As shown in Fig

4.1.

Figure 4. 1 Example of the analysis of a two component mixture (http://www.nature.com/nprot/journal/v9/n8/fig_tab/nprot.2014.128_F5.html) The Rf Value can provide corroborative evidence to identify compounds.

In this case, a standard sample (original dye) was spotted and ran on a

TLC plate side by side with the compound in question under identical chromatography condition.

Figure 4. 2 TLC test for modified dye (left) and original dye

In Fig 4.2, the left spot represents the movement of modified dye, the right side spots stands for original dye (MX-2G). As can be seen from Fig

4.2, two spots (Lower spot: A, higher spot B) are located on the right side.

This could attribute to the hydrolysis of original dye (MX-2G Blue). As mentioned in section 2.1.1.2, the purity of commercial dye MX-2G Blue was not 100%. Part of the original dye was possibly hydrolysed during storage. The polarity of the MX-2G Blue and hydrolysed MX-2G Blue were different, and thus they can travel different distance on silicon surface. In this way two spot can be observed from the original dye pathway (right side).

As seen in Fig 4.2, the modified dye (left side) travel distance was different from the original dye (spot A and spot B).

The travel distance and Rf Values are measured as below.

Distance of solvent travelled =6.9 cm

Distance travelled by modified dye: 1.29 cm

Distance travelled by commercial dye A: 1.70 cm

Distance travelled by commercial dye B: 2.26 cm

Rf Value of modified dye = 0.187

Rf Value of commercial dye A= 0.246

Rf Value of commercial dye B= 0.327

As the two substances have different Rf Values, they are definitely different compounds.

4.1.2 FT-IR

The spectras of commercial dye (MX-2G) and synthesised dye are shown in Fig 4.3 and 4.4. .

Figure 4. 3 Spectrum of MX-2G Blue

Figure 4. 4 Spectrum of synthesised phosphonic acid containing dye The FT-IR spectrum for the MX-2G dye shows the absorbance of C-Cl band at 797 cm-1. Comparing with the starting dye, it can be seen there is no C-Cl absorbance at 797 cm-1 of spectrum for the synthesised

phosphonic acid containing dye. This shows that the dye has reacted, either been converted to the new phosphonic acid containing dye or hydrolysed during the synthesis pathways.

The spectrum of the synthesised phosphonic acid containing dye shows a new, high intensity absorbance band at 1100 cm-1, which stands for P=O stretching (aliphatic). A medium intensity absorbance at 910 cm-1 can be attributed to P-O stretching (P-OH bonds). The identification values are referenced from Characteristic Infrared Absorption Frequencies

(Silverstein et al. 1998; Solomons et al. 2001). This new peak illustrates at least proportional dye was converted.

4.2 Application of synthesised phosphonic acid containing dye to cotton

4.2.1 Effect of Catalyst type and Concentration on dye fixation via Pad-bake method

As described in section 2.2, in order to investigate the effect of catalyst type and catalyst concentration on dye fixation, the pad liquors were prepared containing cyanamide and dicyandiamide at varying concentrations (0, 30, 60, 90, 120 and 150 g dm-3). The dye performance can be assessed by measuring the Absorbance of coloured solutions before and after wash off through UV-visible spectrophotometry.

As mentioned in section 3.3, a number of accurately known concentration solutions of the dye were made up (standard solutions). The wash off 98

solutions is unknown and the concentration of dye in the wash off solutions can be determined by measuring their absorbance. According to

Beer’s law, the amount of radiation absorbed, i.e. absorbance, directly proportional to concentration (O. Thomas & C. Burgess, 2007). Hence, as the concentration of a compound dissolved in solvent increases, the absorbance of the solution should also increase proportionally. Taking advantage of this relationship, these standard solutions should bracket the concentration being identified, some of them may be less concentrated and some may be more concentrated.

For each standard solution, the absorbance at the wavelength of

-1 maximum absorption (λmax) was measured (λmax=611 nm ). Then a calibration plot of absorbance on the y-axis and concentration on the x-axis was constructed for the standard solutions. The plot was constructed in Excel software. A straight line was expected due to Beer’s law as explained earlier. However the law breaks down for higher concentration solutions as dye aggregation may occur. A straight line was drawn through the data points, and extended the line to intersect the starting point. With the help of Excel software, the line can be found by computer. Apart from this, the Excel could also calculate the formula of the line of the calibration plot. In the form y=mx+b. This represents the equation of the calibration line.

The absorbance of the unknown concentration solution is substituted into

the equation in the last step as y, and x can be solved. X represents the concentration of the wash off solution. In this way, the concentration of wash off solution can be obtained. Data is listed below.

Standard solution Concentration Absorbance 0.02g/L 0.35 0.025g/L 0.43

0.033g/L 0.56 0.05g/L 0.87 Table 4.1 Standard solution concentration at corresponding Absorbance.

It is clearly observed from Table 4.2 and Table 4.3 that the absorbance values for wash off solutions are mainly located between 0.3 and 0.7.

Hence the standard solutions which are used to create calibration plot can be selected. As can be seen from Table 4.1, the standard solutions which were chosen represent the absorbance from 0.35 to 0.87. This absorbance range is quite close to the range of wash off solution.

Calibration plot was constructed in Excel, as is shown in the graph below.

Absorbance VS Concentration calibration plot for standard solution 1 y = 17.36x - 0.0014 0.8 R² = 0.9991 0.6

0.4 Absorbance 0.2

0 0 0.01 0.02 0.03 0.04 0.05 0.06 Standard solution concentration (g/L)

100

Figure 4.5 Standard solution plots The equation of the calibration line is y=17.36x-0.0014; R2=0.9991. Both equations indicate this line adheres the Beer’s law. The calibration line equation can be simplified as y=17.36x since the absorbance should be 0 at concentration equal 0 g/L.

The absorbance of wash off solution was measured as described in section 3.3, and the absorbances at the wavelength of strongest absorption are shown below: Wash off solution (not batched) Absorbance 0 g/L 0.63 Dicyandiamide 30 g/L 0.52 Dicyandiamide 60g/L 0.42 Dicyandiamide 90 g/L 0.46 Dicyandiamide 120 g/L 0.42 Dicyandiamide 150g/L 0.39 Cyanamide 30 g/L 0.54 Cyanamide 60 g/L 0.43 Cyanamide 90 g/L 0.45 Cyanamide 120 g/L 0.34 Cyanamide 150 g/L 0.29 Table 4.2 Absorbance at the wavelength of strongest absorption for wash off solutions (not batched)

Wash off solution (batched) Absorbance 0 g/L 0.51 Dicyandiamide 30 g/L 0.48 Dicyandiamide 60g/L 0.45 Dicyandiamide 90 g/L 0.40 Dicyandiamide 120 g/L 0.40 Dicyandiamide 150g/L 0.37 Cyanamide 30 g/L 0.37 Cyanamide 60 g/L 0.36 Cyanamide 90 g/L 0.36 Cyanamide 120 g/L 0.34 Cyanamide 150 g/L 0.30 Table 4.3 Absorbance at the wavelength of strongest absorption for wash off solutions (batched) As seen in the Table 4.2 and Table 4.3, the absorbance y is known. 101

According to the equation of the calibration curve: y (absorbance)

=17.36x (concentration) -0.0014, the concentration x can be calculated.

As shown below. Wash off solution (not batched) Concentration (g/L) 0 g/L 0.036 Dicyandiamide 30 g/L 0.030 Dicyandiamide 60g/L 0.024 Dicyandiamide 90 g/L 0.026 Dicyandiamide 120 g/L 0.024 Dicyandiamide 150g/L 0.022 Cyanamide 30 g/L 0.031 Cyanamide 60 g/L 0.025 Cyanamide 90 g/L 0.026 Cyanamide 120 g/L 0.020 Cyanamide 150 g/L 0.017 Table 4.4 Concentration for wash off solution (not batched)

Wash off solution (batched) Concentration (g/L) 0 g/L 0.029 Dicyandiamide 30 g/L 0.028 Dicyandiamide 60g/L 0.026 Dicyandiamide 90 g/L 0.024 Dicyandiamide 120 g/L 0.023 Dicyandiamide 150g/L 0.021 Cyanamide 30 g/L 0.021 Cyanamide 60 g/L 0.020 Cyanamide 90 g/L 0.019 Cyanamide 120 g/L 0.018 Cyanamide 150 g/L 0.017 Table 4.5 Concentration for wash off solution (batched) All the wash off solutions were kept and volume measured by measuring cylinder. Volume recorded as below. Wash off solution (not batched) Volume (L) 0 g/L 0.42 Dicyandiamide 30 g/L 0.421

102

Dicyandiamide 60g/L 0.417 Dicyandiamide 90 g/L 0.418 Dicyandiamide 120 g/L 0.42 Dicyandiamide 150g/L 0.418 Cyanamide 30 g/L 0.415 Cyanamide 60 g/L 0.417 Cyanamide 90 g/L 0.418 Cyanamide 120 g/L 0.415 Cyanamide 150 g/L 0.421 Table 4.6 Volume measurement for not batched sample wash off solutions

Wash off solution (batched) Volume (L) 0 g/L 0.417 Dicyandiamide 30 g/L 0.425 Dicyandiamide 60g/L 0.42 Dicyandiamide 90 g/L 0.413 Dicyandiamide 120 g/L 0.415 Dicyandiamide 150g/L 0.422 Cyanamide 30 g/L 0.427 Cyanamide 60 g/L 0.419 Cyanamide 90 g/L 0.42 Cyanamide 120 g/L 0.417 Cyanamide 150 g/L 0.422 Table 4.7 Volume measurement for batched sample wash off solutions As the concentration of wash off solution was presented in Table 4.4 and

Table 4.5, the dye being existed in wash off solution can be calculated.

Results are shown as below. Wash off solution (not batched) Dye in wash off solultion (g) 0 g/L 0.0150 Dicyandiamide 30 g/L 0.0120 Dicyandiamide 60g/L 0.0102 Dicyandiamide 90 g/L 0.0110 Dicyandiamide 120 g/L 0.0101 Dicyandiamide 150g/L 0.0094 Cyanamide 30 g/L 0.0130 Cyanamide 60 g/L 0.0105 Cyanamide 90 g/L 0.0110

103

Cyanamide 120 g/L 0.0083 Cyanamide 150 g/L 0.0072 Table 4.8 Dye being existed in wash off solution (not batched samples)

Wash off solution (batched) Dye in wash off solultion (g) 0 g/L 0.012 Dicyandiamide 30 g/L 0.0119 Dicyandiamide 60g/L 0.0109 Dicyandiamide 90 g/L 0.0095 Dicyandiamide 120 g/L 0.0095 Dicyandiamide 150g/L 0.0092 Cyanamide 30 g/L 0.0091 Cyanamide 60 g/L 0.0087 Cyanamide 90 g/L 0.0087 Cyanamide 120 g/L 0.0083 Cyanamide 150 g/L 0.0073 Table 4.9 Dye being existed in wash off solution (batched samples) From section 2.2, the concentration of dye used in each pad liquor (25 mL) is 10g/L. Hench each pad liquor containing 0.25g dye. Since the wet pick up is 74%, the weight of each piece of cotton fabric is 4.45g. After the padding process, the weight of padded sample fabric is 7.74g. In this way, the weight gained, which is the pad liquor padded onto the fabric, is

3.29g. The weight of dye applied on cotton sample fabric is 0.025g.

The dye fixation can be calculated by the equation of the calibration line:

Fixation (%) = [(Dye applied –Dye washed off)/Dye applied]*100

As Table 4.8 and Table 4.9 have listed the weight of dye in wash off solution, following the equation above, dye fixation under various conditions can be obtained. Fixations are listed below. Wash off solution (not batched) Dye fixation (%) 0 g/L 40 Dicyandiamide 30 g/L 52 Dicyandiamide 60g/L 59.2 104

Dicyandiamide 90 g/L 56 Dicyandiamide 120 g/L 59.6 Dicyandiamide 150g/L 62.4 Cyanamide 30 g/L 48 Cyanamide 60 g/L 58 Cyanamide 90 g/L 56 Cyanamide 120 g/L 66.8 Cyanamide 150 g/L 71.2 Table 4.10 Dye fixation for not batched samples

Wash off solution (batched) Dye fixation (%) 0 g/L 52 Dicyandiamide 30 g/L 52.4 Dicyandiamide 60g/L 56.4 Dicyandiamide 90 g/L 62 Dicyandiamide 120 g/L 62 Dicyandiamide 150g/L 63.2 Cyanamide 30 g/L 63.6 Cyanamide 60 g/L 65.2 Cyanamide 90 g/L 65.2 Cyanamide 120 g/L 66.8 Cyanamide 150 g/L 70.8 Table 4.11 Dye fixation for batched samples Display the data in curves as below.

Dye fixation for not batched samples 75

65 60 Dicyandiamide 55 Fixation Fixation (%) Cyanamide 50 45 0 30 60 90 120 150 Catalyst concentration (g/L)

Figure 4. 6 Dye fixation for not batched samples

105

Dye fixation for batched samples 75

65 60 Dicyandiamide

Fixation Fixation (%) 55 Cyanamide 50 0 30 60 90 120 150 Catalyst concentration (g/L)

Figure 4.7 Dye fixation for batched samples

Dye fixation for Dicyandiamide 75

60 No batched Fixation Fixation (%) 55 Batched

50 0 30 60 90 120 150 Dicyandiamide concentration (g/L)

Figure 4. 8 Dye fixation for Dicyandiamide under batch and not batch conditions

Dye fixation for Cyanamide 75

60 No batched

Fixation Fixation (%) 55 Batched 50

45 0 30 60 90 120 150 Cyanamide concentration (g/L)

Figure 4. 9 Dye fixation for Cyanamide under batch and not batch conditions

106

Fig 4.6 and Fig 4.7 show the effects of increasing concentration of dicyandiamide and cyanamide catalyst on dye fixation. Meanwhile Fig

4.8 and Fig 4.9 reveal the effects of the batching process on dye fixation.

The results given in Fig 4.6 and Fig 4.7 show that the degree of synthesised phosphonic acid containing dye of the fixation is related to the catalyst (dicyandiamide and cyanamide) concentration. Generally, the higher the concentration of catalyst, the higher the level of dye-fibre bonding that can be achieved. Good dye fixations are obtained when concentration above 120 g/L of either catalyst are used. On the other hand, the fixation of dye is specifically sensitive to cyanamide. In a manner of speaking, the reaction of the cellulose with phosphonic acid containing dye is more efficient in the presence of cyanamide as compared to that of dicyandiamide.

Fig 4.6 and Fig 4.8 indicate that the batching step does not have substantial effect on dye fixation in the high level catalyst concentration, whether dicyandiamide or cyanamide are used. In the low level of catalyst concentration, the batching step is seen promote the dye-fibre bonding as indicated by a higher fixation value. This is in agreement with the researchers where Gillingham says specifically what they have found

(Gillingham, et al. 2007). This phenomenon demonstrates that slow diffusion is a possible factor that affects dye fixation. Since the phosphonic acid containing dye consists of large molecule, high level

107

catalyst concentration will break down the dye molecule in aqueous solution. Thus promoting the dye diffusion into cellulosic fibre and resulting in high levels of dye fixation (Gillingham et al. 2007).

4.2.2 Effect of Catalyst type and Concentration on dye fixation via Inkjet printing

As mentioned in section 3.1, the total colour difference is measured by spectrophotometer. TheΔL* indicates lightness difference. The results are shown below. Cyanamide concentration Blank area (L*) Jetprinted area (L*) ΔL* 0 g dm-3 92.99 70.45 22.54 30 g dm-3 93.02 65.41 27.61 60g dm-3 92.78 66.62 26.16 90g dm-3 92.65 60.46 32.19 120g dm-3 92.65 61.08 31.57 150g dm-3 91.46 56.05 35.41 Table 4.12 Lightness for inkjet printing samples treated with Cyanamide

Dicyandiamide concentration Blank area (L*) Jetprinted area (L*) ΔL* 0 g dm-3 92.99 70.45 22.54 30 g dm-3 92.49 66.26 26.23 60g dm-3 93.19 68.5 24.69 90g dm-3 93.29 67.13 26.16 120g dm-3 92.83 65.42 27.41 150g dm-3 93.42 66.74 26.68 Table 4.13 Lightness for inkjet printing samples treated with Dicyandiamide For the sake of direct display and more detailed, convert the Table 4.12 and Table 4.13 to diagram.

108

Colour difference of inkjet printed samples 40

L* 30 Δ Cyanamide 25 Dicyandiamide

20 0 30 60 90 120 150 Catalyst concentration (g/L)

Figure 4.10 Colour difference of inkjet printed samples As can be seen from Fig 4.10, the inkjet printed cellulosic samples show the same trend as the samples treated by the pad-bake application method.

Normally, the lightness of phosphonic acid containing dye treated cotton is proportional to the catalyst (dicyandiamide and cyanamide) concentration. The higher the concentration of catalyst, the lower the lightness that can be achieved. Since in CIE L*a*b* system, L* is a measure of the lightness of an object and ranges from 0 (black) to 100

(white), lower values of L* indicate darker shades. Hence L*can also be related to the degree of dye fixation. The reaction of the cellulose with phosphonic acid containing dye is thus seen more efficient in the presence of cyanamide than in the presence of dicyandiamide also for inkjet printing application.

Actually it is seen in the literature that the performance of cyanamide/dicyandiamide-phosphonic acid containing dye reaction is still debated. In this research, cyanamide has superiority to dicyandiamide. 109

Early researches have explored the role of cyanamide in the dye-fibre bonding reaction. One proposal is that cyanamide will promote phosphonic anhydride intermediate formations shown in Fig 4.11.

Figure 4.5 Anhydride formation from a phosphonic acid dye in the presence of cyanamide & reaction of the said anhydride with cellulose (Dye represent the chromophore and cell represent cellulose residues). Apart from this marked action, it has also been proposed that the dye could generate free phosphonic acids undertake thermal dissociation and then react with cyanamide to give a cationic adduct (Amato et al. 1987), as shown in the Fig 4.12 below.

Figure 4.6 Reactive cationic intermediate formation from a phosphonic acid dye in the presence of cyanamide & reaction of the said adduct with cellulose (Dye represents the chromophore and cell represenst cellulose residues).

For dicyandiamide, the fixation mechanism of phosphonic acid dye to cellulose is simplified in Fig 4.13 (Renfrew and Taylor, 1990).

110

Figure 4.7 Mechanism of phosphonic acid dye to cellulose via dicyandiamide catalyst (Cell represents the cellulose residues). Dicyandiamide could also react with the free phosphonic acids generated from the dye. The mechanism would be identical as that presented in Fig

4.13.

As reviewed in section 1.1.2.3, the reaction of the phosphonic acid dye with cellulose is basically an esterification process that result in the cross-linking of cellulose molecules between dye and cellulose via a reaction with cyanamide/dicyandiamide. The cross-links are a type of phosphonic acid ester. Essentially speaking, the extent of esterification that has been achieved determines the extent of dye fixation onto the cellulosic fibre. From the above, a feasible reason why cyanamide performs more efficiently than dicyandiamide in inducing dye fixation is the low yields of phosphonic acid ester obtained in the presence of dicyandiamide compared with cyanamide.

Another possible interpretation could be that compared with dicyandiamide, cyanamide is a relatively low molecular weight compound. The molecular weight of cyanamide is 42.04 g/mol, 111

meanwhile the molecular weight of dicyandiamide is 84.08 g/mol.

Furthermore dicyandiamide is comparatively hydrophobic and has low water solubility at room temperature. However, Cellulose is hydrophilic.

As a result, the cellulose may take up less dicyandiamide from solution during the application process. Molecular size is known to be a vital factor in dye diffusion. Additionally, the catalyst-dye adduct must exist inside the fibre prior to dye-fibre bonding (Burlington Industries Inc,

1978) It may be that the adduct is first formed, in which case a dye-cyanamide adduct may be expected to have higher diffusivity due to lower molecular weight than a dye-dicyandiamide adduct. Alternately, both dye and catalyst may react in situ. In such case, the substantivity of the catalyst, and hence possibly their solubility, will be relevant. In this way, cyanamide can be more effective in promoting the dye-fibre bonding.

Cyanamide not only acts as a catalyst for dye fixation but also plays a role in enhancing dye solubility during the dyeing process when dye diffusion is occurring.

4.2.3 Effect of printing method on colour strength

According to the visual observation and colour strength test from spectrophotometer (Fig 4.14 and Fig 4.15), the inkjet printed cellulosic samples show a clear increase in colour strength (L*) as compared to the padded samples. At the same catalyst concentration level, inkjet printed

112

fabric always consistently higher lightness compared with padded fabric

(Lower value of L* stands for darker shade). A couple of interpretation could explain why this happen.

Lightness 85 80 75

70 L* 65 Jetprinted fabrics 60 Padded fabrics 55 50 0 30 60 90 120 150 Cyanamide concentration g/L

Figure 4.8 Lightness VS Cynamide concentration

Figure 4.9 Comparison between inkjet printing sample (left) and pad-bake sample. As mentioned in section 1.1.2.2, inkjet printing is a non-contact technology. By projecting tiny drops of liquid ink onto the cellulosic substrate, image formation can be achieved through dye fixation taking place in fibre. A single DOD drop deposited on cotton fabric is knows to be only 41.6 picoliter (Carr et al. 2008). Thus, only very small amount of dye applied is on cotton through each printing. As seen in a micrograph

113

taken by SEM (Fig 4.16), a single drop is about 2 to 3 fibres size (Carr et al. 2008). The fibre size is approximately 20μm. This indicates the relative size of the ink drops. Nonetheless, as in inkjet printing, brilliant and sharp colour is obtained by dye molecules fixed on or near the substrate surface (H. Ujiie, 2006).

Figure 4.10 Ink distribution in cotton fibre (Inkjet deposition of complex mixtures to textiles, 2008) As the number of drops increased, the ink spread along the fibre direction as opposed to the transverse direction. The drop distribution on cotton is affected by the yarn direction and interactions. From Fig 4.17, it is clearly to see that the accumulated ink drops prefer to stay on one yarn until excess ink moved to neighboring yarns (Carr et al. 2008). With the help of optical microscope, it is observed that drops spread along the yarn weft and weft direction rather than the transverse direction.

114

Figure 4.11 Drops deposited on the cotton fabric(Inkjet deposition of complex mixtures to textiles, 2008) . In the padding process, the sample fabric is evenly impregnated.

Specifically, the pad liquor is decanted into the padding trough, and cotton fabric was fed in to squeeze roll. The uniform expression of the pad liquor was achieved by passing the cotton fabric through the arranged rolls, as cotton emerged from the trough. Under the pressure, dye molecules could diffuse into cellulose fibre quite quickly and deep in both fibre direction and transverse direction. Fibres act as a kind of barrier for dye spreading in the transverse direction. Whereas in the padding process, pressure and aqueous solution would facilitate dye transport further into the fabric. To put it briefly, dye used in padding process would transport into internal or core yarns of the fabric, or even exist within the gap between neighboring yarns.

115

The penetration of the ink into the fabric will influence the colour strength and print quality. In accordance with the studying of Kaimouz

(Kaimouz et al. 2010), increase ink penetration into fabric would result in the decrease in the visual colour strength. Compared with inkjet printed fabric, padded cellulosic fabric possesses higher degree of dye penetration. For inkjet printing, less penetration into the fabric results in most of the dye located on the fabric surface or the upper layer of the substrate. Thus stronger color can be achieved.

Apart from the dye location, catalyst padded on cellulosic substrate prior inkjet printing also affect the colour strength. As all the samples were padded with sample level of dicyandiamide /cyanamide, the amount of catalyst deposited on cellulosic fabric is equal. As discussed in the above, only a small amount of dye is deposited on the surface or upper level of fabric for inkjet printed samples. Under the same catalyst concentration conditions, it is proposed that more catalyst would be available to promote dye-fibre bonding reaction in the upper level of inkjet printed cellulosic substrate. For padded cotton samples, dye deposited not only on the surface but also in the core fibre. Hence the ratio of Catalyst to dye for inkjet printing is much higher than that in padding application.

Furthermore, a steady increase in dye fixation with increased catalyst concentration can be observed (Fig 4.14). Hence it is probable that an increase in effective catalyst: dye ratio is the reason why inkjet printing

116

actually performs higher visual depth degree of fixation under the same level of catalyst.

Further, additional experiments in laboratories have supported this contention. For example, the lightness of inkjet printed sample under different cyanamide concentration indicates the increase of catalyst concentration would result in the decrease of L*, as seen in Fig 4.18.

Lower value of L* stand for darker shade. L* is a measure of the lightness of an object and ranges from 0 (black) to 100 (white).

Cyanamide 75 70 65

60 y = -0.0868x + 69.856 L* 55 R² = 0.8982 50 45 40 0 30 60 90 120 150 Concentration (g/L)

Figure 4.12 L* for inkjet printing via Cyanamide As we can see from the trendline from Fig 4.18, we are not yet reaching a plateau level at concentration of 150 g/L. This trendline has a good fit and shows the potential for further development: higher catalyst concentration result in lower colour strength. In section 4.2.1, Fig 4.6 and Fig 4.8 show the relationship between catalyst concentration and fixation through pad-bake method. As we can see that the fixation line flat out as increase in catalyst concentration. However in inkjet printing the direct 117

relationship indicates that the shade would get darker when the concentration of catalyst keeps increasing. This also strengthens the argument above that in inkjet printing the higher catalyst to dye ratio can be achieved.

Further investment could keep on trying how higher catalyst concentration may affect the colour strength.

4.3 Effect of pretreatment and baking process on tensile strength

As mentioned in section 3.2, five pieces of specimen were tested via

Instron tensile test machine. As seen in Table 4.14.

Pretreated Printed with phosphonic acid baked Wash off containing dye

sample 1 Cyanamide √ √ √

sample 2 Dicyandiamide √ √ √

sample 3 / √ √ √

sample 4 / √ √

sample 5 / √ Table 4.14 Sample preparation This test was designed to assess the effects of dye application on strength retention of the cotton substrate. Especially investigate will dye and bake process affect tensile strength during printing process.

As seen in Fig 4.19, three samples were printed via inkjet printing. One sample was not pretreated with catalyst, and displays a higher value of tensile strength. From this point, pretreatment on cotton prior to printing

118

contributes to lowering the strength level.

Tensile Strength (N/m2) 12

11.5

2 10.5

N/m Tensile Strength 10

9.5

9 Sample 5 Sample 4 Sample 3 Sample 2 Sample 1

Figure 4.19 Tensile strength for print-bake samples The effect of short thermal treatment on cotton tensile strength can be seen from Fig 4.19. The tensile strength actually remains intact after the samples are thermally treated for a short time (less than 4 min). A less than 4% loss in tensile strength could associate with small changes in the fine physical structure of cellulose. Early researches demonstrate that during the thermal treatment cellulose undergoes decrystallization and recrystallization. Loosening of the cellulose structure may alter surface friction and the interaction of the fibres and yarns which make up the structure (Hebeish et al. 1979). The magnitude of tensile strength loss is dependent on the temperature and duration. Cotton fabric can be handled at the relatively high temperatures (approximately 180ºC) in a short time without immediate catastrophic damage occur.

From Fig 4.18, compared with baked only sample (no pretreatment and printing process), the printed and pretreated samples show low level of 119

tensile strength. This phenomenon demonstrates that the phosphonic acid dye surely tenderized cotton fabric and result to strength reduction. We thus propose that the strength loss observed in the printed samples is associated with dye fixation. As mentioned in section 1.1.2.3 and 1.1.2.4, dye-fibre bonding formed after dye applied on cotton fabric surface. The reaction between dye reactive group and reactive site on cellulosic fibre would affect the degree of polymerization and slightly change the fine physical structure of cellulose fibre. Thus a decrease in the degree of polymerization could occur and result in a loss in tensile strength. The below table shows the relationship between inkjet printed fabric colour strength and tensile strength. Colour strength (L*) Tensile strength (N/m2) Pre-treat with Cy and inkjet print 56.05 9.81 Pre-treat with Di and inkjet print 66.74 10.29 No pre-treat & print (bake only) 93 11.32 Table 4.15 Tensile strength Convert this Table 4.15 to plot, as shown in Fig 4.20.

120

11.4 11.32

11.2

) 2 11 10.8 10.6 10.4 10.29 10.2

Tensile Tensile strength(N/m 10 9.8 9.81 9.6 0 20 40 60 80 100 Colour strength (L*)

Fig 4.20 Tensile strength VS Colour strength Fig 4.20 clearly indicate that a level of proportionality commensurate.

Cotton fabric pre-treated with cyanamide displays the best performance and thus has the highest tensile strength loss.

Our aim in inkjet printing was to limit dye deposition to the surface.

Hence we presume that the damage to cellulosic substrate observed via the tensile strength loss is similarly to the surface of the fabric. Although a significant degree of tenderizing was presumably achieved totally, the overall integrity & tensile strength of the fabric is not compromised.

Finally, resulting to acceptable levels of strength loss.

121

5. Conclusion

The aim of this research was an investigation of the influence of phosphonic acid group in dye-fibre bonding between modified reactive dye and cellusic fabric, via a pad-bake process to yields suitable conditions for subsequent inkjet printing. A commercial dichloro-triazine dye (Blue MX-2G) was selected as the original dye, and through chemical reaction a new phosphonic acid containing dye was synthesised.

Compared with the MX-2G, phosphonic acid groups were added on the reactive system. The sodium salt of the original dye was converted to the ammonium salt. The synthesised phosphonic acid containing dye was applied to cotton via pad/pad-batch-bake process and subsequent inkjet printing process at varying amount of the catalyst (Dicyandiamide and

Cyanamide). One half of each padded sample was batched prior to drying process. Washing off process was carried out on all padded and printed samples. Dye fixation and colour strength were measured and the results are shown in Table 4.10, 4.11, 4.12 and 4.13. The influence of modified dye on cotton fabric was also assessed by Tensile Test, results are displayed in Fig 4.17 and 4.18.

Results of the investigation led to the following conclusions:

Based on the analysis on Fig 4.3 and Fig 4.4, phosphonic acid containing dye can be synthesised. Cl atom can be substituted by phosphonic acid group through the method used in this research. Using the existing

122

synthetic method, phosphonic acid group can be introduced to certain commercial dye.

Batching process used prior drying had a small effect on dye fixation promotion at high dicyandiamide and cyanamide concentration (above

120 g/L). Under low catalyst concentration conditions, the large dye molecules diffused into cellulosic fibre at slow migration. While higher catalyst concentration can significantly improve the dye diffusion process.

In this way, high concentration of catalyst would be advantageous for pad-bake process.

The dye fixation results clearly demonstrate that the covalent bonding between dye and fibre is sensitive to catalyst concentration. By incorporating cyanamide/dicyandiamide in the padding solutions, the padded sample fabrics offer higher level of dye fixation than non-catalyst treated cotton fabric. The same phenomenon happened on inkjet printed fabrics, as the pre-treated catalyst containing samples offer higher level of dye fixation. As the increase in catalyst concentration, the rise in dye fixation can be seen according to the results depicted in Fig 4.6, 4.7, 4.8 and 4.9. Pad-bake method and inkjet printing both present this trend.

Cyanamide always displays a better performance in both pad-bake process and inkjet printing. As analysed in section 1.1.2.2, the phosphonic acid groups other electron donatting groups are pivotal parameters in influencing the dye fixation level and the colorimetric data of the

123

phosphonic reactive dye and dye-based ink on cellulosic substrate.

Possible explanation is that cyanamide probably promotes the generation of the free acids during baking, leading to cations from the dye counter the negative charged cellulosic fibre and thus more and more dye anions absorbed on the fabric. Eventually promote the esterification between dye-fibre reactions and offer a relatively high level of dye fixation.

Under the same level of dye and catalyst applied on cotton fabric, inkjet printing method offered a higher level of colour strength when compared with pad-bake method. This phenomenon could attribute to the dye molecules are mainly deposited on the surface or upper level of cellulosic fabric through inkjet printing, as in pad-bake process dye molecules are penetrated in bulk of cellulose fibre. Since the dye molecules through padding process were distributed in both yarn direction and transverse direction, dye-fibre bonding happened not only on the surface of fabric, but also in the interior yarns. It is clearly to see the darker shade of inkjet printed fabric is only appeared on face side, meanwhile both sides of the padded fabric appeared lighter shade.

The tensile test results indicate the phosphonic acid containing dye will damage cotton fabric slightly. Since the tensile strength of printed fabric is lower than the unprinted and the plain cotton samples. The reduction of tensile strength is within an acceptable range.

However, the drawback to this phosphonic acid containing dye is that dye

124

fixation is dependent on the concentration of catalyst. Only high concentration of cyanamide or dicyandiamide can present high dye fixation value.

5.1 Recommendations for future research

In this research, it is shown that the phosphonic acid containing dye can be converted, and some objectives are achieved. However, there are some recommendations for further research and development.

Even the dye was converted as expect, improvement in synthetic method to achieve better conversion can be investigated.

Depending on the research of effect of catalyst concentration, future investigates in how high level catalyst concentration result in high fixation could be carried out.

Apart from these two points, the use of thickener in pre-treatment to prevent or minimum the cellulosic substrate damage from dye-fibre reaction. Hold on the ink where it drops and keep the dye in the surface, thus the cotton affected by the reaction is minimum. This is worth for the further study.

As in this research, wash fastness has never been assessed. As a matter of fact, wash fastness is a quite important factor in dye applying process.

The future research could carry out the wash fastness assessment on dyed and printed fabrics. Such assessment would provide the loss and change of colour in the washing process by a consumer and the lighter portion

125

that may be washed with it.

5.2 Future of Inkjet printing

Inkjet printing is one of the states of printing technique in textile market, available in terms of quality, productivity assured reproducibility in spite of initial high investments. It can speed up the process between design and industrial production. Meanwhile, the first time Just In Time production can be realized through this technology. That way huge reduced concept-to-consumer time frames can be achieved, all level inventory risk and high level stock could be avoid as a result. The competition between inkjet printing and conventional printing will continue. Conventional printing will keep up to be used in textile industry where the products are produced in long runs and time-to-market is not a critical issue. In the meantime, inkjet printing will aim to premium textile market, customized textile products and for the products where time-to-market is critical.

126

6. Reference

1. Franco Phj & Valadez-gonzalezM. (2005), ―Fibre-matrix adhesion in

natural ﬁbre composites". In Mohanty, A.K.Natural ﬁbres,

biopolymers and biocomposites, CRC, Boca Raton, p.37.

2. S. Gordon & Y-l. Hsieh (2007), Cotton: science and

technology, Woodhead, Cambridge.

3. P. J Wakelyn (2007), Cotton fiber chemistry and technology,CRC,

Boca Raton.

127

4. Art Quill Studio (2014). Cellulosic Fibers (Natural) – Cotton Art

Resource. Available from:, The Education Division of Art Quill & Co.

Pty. Ltd. Web site:

http://artquill.blogspot.com.au/2014/02/cellulosic-fibers-natural-cotto

n-1-3.html [Accessed: April 29, 2014].

5. Cousey H. a & Smith S.b (1996), The Formation and Structure of a

new Cellulose Fibre, Lenzinger Bericht, pp.51-63.

6. Leslie Mile, W. C. (2003), TEXTILE PRINTING, 2nd ed, Society of

Dyers and Colourists, Manchester. pp. 1.

7. Robert R Mather & Roger H Wardman (2011), The Chemistry of

Textile Fibres, The Royal Society of Chemistry, p.23.

8. M. Sfiligoj Smole, S. Hribernik & K. Stana Kleinschek (2013), "Plant

Fibres for Textile and Technical Applications". In Advances in

Agrophysical Research, InTech, p.373.

9. Xiangwu Zhang (2014). Fundamentals of Fiber Science, DEStech

Publications, pp.65-68.

10. Aleen G. Cohen & Ingrid Johnson (2012), "Yarns and Sewing

Threads". In Fabric Science, Fashion Institute of Technology, New

York, pp.69-73.

11. Julie Parker (1998), All About Cotton: A fabric dictionary and

swatchbook, 2nd ed, Rain City Publishing, Seattle, p. 10.

12. Phillip J. Wakelyn, Barbara A. Triplett & J. Vincent

128

Edwards(2007), Cotton fibre Chemistry and Technology,3rd ed, CRC

Press, Boca Raton, p. 63.

13. K. Stana-kleinschek & V. Ribitsch (1998), "Electrokinetic properties

of processed cellulose fibers". In Colloids Surfaces A: Physicochem,

pp.127-138.

14. Klemm D, Heublein B & Fink H-p (2005), "Cellulose: Fascinating

Biopolymer and Sustainable Raw Material",Angewandte Chemie

International Edition, vol. 44, no. 22, pp. 3358-3393.

15. Maya Jacob John & Sabu Thomas (2008), "Biofibres and

biocomposites", Carbohydrate Polymers, vol. 71, no. 3, pp. 343-364.

16. Robert J. Moon, Ashlie Martini & Jeff Youngblood (2011), "Cellulose

nanomaterials review: structure, properties and

nanocomposites", Chemical Society Reviews, vol. 40, no. 7, pp.

3941-3994.

17. Gordon S & Hsieh Y-l (2007), "Chemical structure and properties of

cotton". In Cotton: Science and Technology, WoodheadPublishing,

18. R. H. Attala and A. Isogai (2005), Recent developments in

spectroscopic and chemicalcharacterization of cellulose, Marcel

Dekker, New York. pp123-157.

19. Fink, H.-P, Walenta, E. (1994) ―Röntgenbeugungsuntersuchungen zur

übermolekularen Struktur von Cellulose im Verarbeitungsprozeß‖,

129

Papier 48, pp. 739-748.

20. John Mj, Thomas, S (2008), "Biofibres and

biocomposites",Carbohydr. Polym, vol., no. 71, pp. 343-364.

21. Moon Rj, Martini A, Nairn J, Simonsen J, Youngblood J (2011),

"Cellulose nanomaterials review: structure, properties and

nanocomposites", Chem. Soc, no. 40, pp. 3941-3994.

22. Hult E-I, Iversen T, Sugiyama J (2003), "Characterization of the

supermolecular structure of cellulose in wood pulp fibres", Cellulose

10, vol., pp. 103-110.

23. Kim U-j, Eom SH, Wada M (2010), "Thermal decomposition of

native cellulose: Influence on crystallite size", Polym. Degrad. Stab,

no. 95, pp. 778-781.

24. Hardy BJ, Sarko A (1996)‖ Molecular dynamics simulations and

diffraction-based analysis of the native cellulose fiber: structural

modeling of the Iα Iβ

Polymer, no, 37, pp1833-1839.

25. Rattee, I. D. & W. Stephen, (1956), British Patents 772030,774925,

and 781930 (to ICI Ltd.).

26. David M Lewis (1998), "Dyestuff–fibre interactions",Coloration

Technology , vol. 28, no. 1, pp. 12-17.

27. Arthur D Broadbent (2001), Basic Principles of Textile Coloration,

Society of Dyes and Colourists, pp332-333.

130

28. John Shore (2002), "Colorants and auxiliaries.‖ Society of

Dyers and Colourists, vol. 1, pp. 358-360.

29. John Shore (1995), Cellulosics Dyeing, Society of Dyers and

Colourists,pp193-194.

30. T E Peacock (1965), Electronic properties of aromatic and

heterocyclic moledules, London Academic Press, pp103

31. J Shore (1990), Colorants and Auxiliaries: Vol 1. Published by

Society of Dyers and Colourists, Bradford.

32. Peter J. Dolby (1977), "The dyeing of fibres with reactive dye".

In International dyeing symposium, Practical dyeing problems,

A.A.T.C.C, pp.25-26.

33. John Shore (2002), Colorants and auxiliaries: Organic chemistry and

application properties, Society of Dyers and Colourists, pp.363-365

34. Zollinger. H (1991), Color Chemistry, VCH, Weinheim, p227.

35. John Shore (1995), Cellulosic Dyeing, Society of Dyers and

Colourists, pp225-226.

36. Leslie. W. C. Miles (2003), Textile Printing, 2nd , Society of dyers

and colourists, pp301-303.

37. A Teunissen, M Kruize and M Tillmanns (2002), Developments in the

Textile Printing Industry, Boxmeer: Stork Textile Printing Group.

38. Ross T (2004), A primer in digital textile printing. Available from:

http://www.techexchange.com/thelibrary/DTP101.html [Accessed:

131

May 9, 2014].

39. Chris Byrne (2001), Inkjet Printing in the Textile Industry: Drawing

up the Battlelines. Available from:

http://www.digitaltextile.net/archive/articles/overview2001.html

[Accessed: May 9, 2014].

40. K Venkataraman (2012). The Chemistry Of Synthetic Dyes V6:

Reactive Dyes, Elsevier: London, pp409-410.

41. Alexandre Paprocki, Heldiane S. Dos Santos & Marta E.

Hammerschitt, 2010, Ozonation of azo dye acid black 1 under the

suppression effect by chloride ion. Journal of the Brazilian Chemical

Society, 21(3).

42. B. L. Mcconnell, L. A. Graham & R. A. Swidler, 1979, A New

Reactive System for Continuous Dyeing and Printing of Cellulose and

Blends. Textile Research Journal, 49, pp.458.

43. A. Soleimani-Gorgani, M. Pishvaei (2011), Water fast ink Jet print

using an acrylic /nano-silver ink, Color Colorants Coat, pp79-83.

44. S. O. Aston, J. R. Provost, H. Masselink (1993), Jet printing with

reactive dyes, J. Soc. Dyers Color., vol 109, pp147-152.

45. B. Glover (2005), Reactive dyes for textile printing, Colorage,

pp67-82.

46. Holly Brackmann (2006), The Surface Designer's Handbook,

Interweave Press, pp 15-16

132

47. Harold S. Freeman, Leon S. Moser & Wilson M. Whaley, 1988, New

Phosphonic Acid Reactive Dyes for Cotton. Dyes and Pigments , 9

pp.57-65.

48. Douthwaite, F. J. N. Harrada, T. Washimi (1996), Proceedings

IFATCC Conference, Vienna, pp447-451.

49. ID Rattee and M M Breuer (1994), The Physical Chemistry of Dye

Adsorption, Academic Press, London, p. 182.

50. Schneider R (2004), "Minimization of water consumption in

European textile dyeing and printing industry using innovative

washing and recycling technologies". InInnowash econfidential

progress reports of EU project.

51. P. Moulin, M. Maisseu, F. Charbit (2006), "Treatment and reuse of

reactive dyeing effluents,Journal of Membrane", Science, vol. 269, no.

pp. 15-34.

52. Jane Spencer (2007), Available from:

http://online.wsj.com/news/articles/SB118580938555882301

[Accessed: April 9, 2014].

53. A H M Renfrew, J a Taylor (1990), "Cellulose Reactive Dyes: Recent

Development and Trends", Journal of the Society of Dyers and

Colourists, vol. 20.

54. M E Amato, S Fisichella and I D Rattee (1987), "The dyeing of cotton

with phosphonic reactive dyes in alcohols",Issue Journal of the

133

Society of Dyers and Colourists Journal of the Society of Dyers and

Colourists, vol. 103, no. 12, pp. 434-437.

55. Tincher WC & Hu Q (1996), Recent progress of inkjet technologies II.

The Society forImaging Science & Technology’s Publication, pp.

366–369.

56. Mineral Adsorbents (2014), Filter Agents and Drying Agents.

Available from:

http://www.sigmaaldrich.com/chemistry/chemical-synthesis/learning-

center/technical-bulletins/al-1430/molecular-sieves.html [Accessed:

June 4, 2014].

57. Siladitya Behera*, Subhajit Ghanty, Fahad Ahmad, Saayak Santra,

and Sritoma Banerjee (2012), UV-Visible Spectrophotometric Method

Development and Validation of Assay of Paracetamol Tablet

Formulation, Department of Quality Assurance and Pharma

Regulatory Affairs, Gupta College of Technological Sciences, West

Bengal, India.

58. Kan, C.W., Chan, K. and Yuen, C.W.M (2000), ―Application of low

temperature plasma on wool - Part III: Surface Chemical and

structural composition‖, The Nucleus, 37(3-4), pp. 145-159.

59. R. M. Silverstein, F. X. Webster (1998), Spectrometric Identification

of Organic Compounds, 6th edition, Wiley, New York.

60. T. W. G. Solomons, C Fryhle (2001), Organic Chemistry, 7th edition,

134

Wiley, New York.

61. Manfred, H., Meier, H. and Zeeh, B. (1997), Spectroscopic Methods

in Organic, Chemistry, New York: George Thieme.

62. Lambert, J.B., Shurvell, H.E., Lightner, D.A. and Cooks, R.G. (1998),

Organic Structural Spectroscopy, N.J.: Prentice Hall.

63. O. Thomas & C. Burgess (2007), UV-visible spectrophotometry of

water and wastewater, Elsevier, Amsterdam.

64. M E Amato, S Fisichella and I D Rattee(1987), ―The dyeing of cotton

with phosphonic reactive dyes in alcohols‖, J.S.D.C., 103, p. 434

65. A H M Renfrew & J a Taylor (1990), "Cellulose reactive dyes:recent

developments and trends", Rev. Prog. Coloration, vol. 20, pp. 5-8.

66. Estelle L Gillingham, David M Lewis, Asfia Nabi and Kawee

Srikulkit (2007), "Triazinylamino-alkylphosphonate reactive dyes for

cellulosic fibres", Society of Dyers and Colourists. no. 123, pp.

178-183.

67. BurlingtonIndustries Inc (1978), BP 1 514 395.

68. H. Ujiie (2006), Digital printing of textiles, Woodhead Publishing

Limited, Cambridge, pp 255-257.

69. W.W. Carr, D. G. Bucknall, J. F. Morris (2008), ―Inkjet deposition of

complex mixtures to textiles‖ in National Textile Center Annual

Report.

70. A W Kaimouz, R H Wardman and R M Christie (2010), ―Ink-jet

135

printing process for lyocell and cotton fibres. Part 2: The relationship

of colour strength and dye fixation to ink penetration‖, Coloration

Technology, vol 126, pp342-347.

71. A. HEBEISH, A. T. EL-AREF, E. A. EL-ALFI, and M. H.EL-RAFIE

(1979), ―Effect of Short Thermal Treatment on CottonDegradation‖,

Textile Research Division, National Research Centre, Dokki, Cairo,

Egypt, pp. 454-462.

7. Appendix

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182