International Journal of Advances in Science Engineering and Technology, ISSN: 2321-9009, Vol-5, Iss-1, Spl. Issue-3 Mar.-2017 http://iraj.in LIKELY MECHANISM OF DYE ADHESION ON FABRICS

1D. MALOMO, 2S.A ABIMBADE, 3A.K OLUWASEUN, 4O.EGHAREBA

1,2,3Department of Industrial Chemistry, Federal University Oye Ekiti, Nigeria 4Rubber Research Institute of Nigeria, Benin City, Nigeria E-mail: [email protected]

Abstract - The mechanism of adhesion of dyes as colouring agents on different types of fabrics is hereby examined. The dyes under study include, basic dyes, acidic dyes, azo dyes, mordant dyes, and vat dyes while the fabrics are cellulosic materials, wool fabrics, nylon 6,6 fabrics, nylon 6 fabrics, silk fabrics and polyester materials. The principle of adhesion proposed leading to the fastness of the colourants is illustrated by the bonding of atoms and molecules arising from intermolecular interactions between functional groups of the dyes and the substrate materials. The functional groups involved are hydroxyl group (-OH), carboxylic group (-COOH), carbonyl group (=C=O), imino group (-NH-) ester group (- COOR), amide group (-CONH2) as well as conjugation in aromatic groups. The types of bonding proposed are ionic, covalent, dative covalent, dipole-dipole forces, and inter molecular hydrogen bonding. The study also shows that adhesion may be enhanced by physical entrapment of the colouring molecules on the substrate.

Keywords - adhesion, entrapment, bonding, functional group, fabric and dye

I. INTRODUCTION complex, as a member of factors must be considered. This paper set out to examine various types of dyes A dye is a colouring substance that has affinity for the and fabrics as well as present likely mechanistic substrate to which it is being applied (Popoola, 2015) processes by which some selected dyes are adhered It is usually applied in an aqueous solution and may on the surfaces of some chosen fabrics. The study require a mordant to improve the fastness on the will therefore, discuss the nature and chemistry of fabric which are essential fiber material. A fibre dye/fabrics, chemical structures/functional groups being a single elongated piece of a given material present in dye and fabrics as well as various bonding roughly round in cross-section often twisted with types. This information will form the basis of other fibres to form a thread. Dyes posses colour postulating possible mechanism by which dye as a because they absorbs light in the visible region of the colouring material is adsorbed on some fabrics electromagnetic spectrum (400-700nm). They have at surfaces. least one chromophore, colour-bearing group usually with conjugated double bond system. They exhibit II. CLASSIFICATION OF DYES resonance of electrons which is stabilizing force in organic compounds (Abrahat, 2009). Most dyes also Dyes can be classified as organic or inorganic natural contain auxochromes (colour enhancers) and or of synthetic origin. They are also classified by examples includes; Carboxylic acids, sulfonic acid, method of application or by the nature of amino and hydroxylic groups.While these are not chromophores they posses. Natural dyes are obtained responsible for colour, auxochromes are e-donating from natural source such as plants, animal or mineral. groups which shift absorption spectrum towards Roots, nuts and flowers, and leaves contain natural longer wavelength in dye molecule having conjugated dyes. A common example is indigo π-bond system (Popoola, 2015). Example of these Synthetic dyes which are man-made colouring groups include, -CH3 , -OH, -OCH3, -NH2,-NHCH3 substance of organic origin made from coal tar and and –N(CH3)2. They most often influence dye benzene derivatives.. They cost less and have ability solubility. to offer wide range of colours. They are applied Fabric refers to any material made through weaving, applied in medicine, chemistry, plastics, paint, ink, knitting, spreading, crocheting or bonding that may rubber and cosmetics.Dye application for numerous be used in production of further goods such as; surfaces or processes of application form basis for garments. Fabrics are manufactured from various raw another method of classification. Examples include materials which are of natural or synthetic origin or a leather dyes for leather, oxidation dyes for hair, mixture of the two. Essentially fabrics contain fibres optical brightness for paper, solvent dyes for coloured material made of continuous filaments which are lacquers, while others are fluorescent dyes for sports; discrete and elongate like the length of thread pieces. fuel dyes fuels, smoke dyes for military activities, Fabrics are classified on the basis of origin, processes sublimation dyes for textile printing. Ink jet dyes are or its end uses. (Balter, 2009) used for inkjet printers and leuco dyes for electronic The applications of dye on fabrics for the purposes industries and papers. imparting colours to enhance aesthetic value have Classification of dyes based on the chemical been a process as old as civilization. The chemistry composition of a dye is possible and this is associated behind the mechanism of adhesion of dye on fabric is with the chromophore present in the dye. A

Likely Mechanism of Dye Adhesion on Fabrics

1 International Journal of Advances in Science Engineering and Technology, ISSN: 2321-9009, Vol-5, Iss-1, Spl. Issue-3 Mar.-2017 http://iraj.in chromophore is a functional group present in the bonds. This makes the reactive dye a permanent molecule of a dye which imparts the molecule with dyestuff, most ideal for dyeing cotton and some other the ability to absorb uv radiation strongly thereby cellulose fibres.The azoic dyeing technique involves leading to colour generation. Some examples are the application of insoluble azo dye on fibre by direct listed include the following: contact using a coupling component.The toxic nature of the chemicals used is now responsible for decline Table 1: Examples of chromophores and some applications in applicatio. The dispense dyes are water- insoluble finely ground materials which in the process of dispersing agent are applied as spray or powdering form on polyester, nylon and acrylic fibres. The dyeing rate can be significantly influenced by choice of dispersing agent used during the grinding process. The sulphur dyes are used to produce dark colours,,they are cheap and it involves reaction between an organic compound such as nitrophenol and sulphide source.

III. SYNTHETIC DYES

A Synthetic dye is any of the organic dyes originally derived from coal-tar derivatives, but currently synthesized from benzene and its derivatives. The

first human-made organic dye, mauveine, was A typical example of a dye structure classified by discovered by William Henry Perkin in 1856. using chromophore is the Yellow azo dye where the Thousands of synthetic dyes have since been double bond in the Azo group –N=N- is in prepared. Synthetic dyes quickly replaced the conjugation with the double bonds in the two traditional natural dyes. They cost less, they offer a aromatic groups. This increases the intensity of vast range of new colours, and they imparted better colour generation.Majority of dyes stuff is primarily properties upon the dyed materials.They are used in consumed by the textile industries and this medicine, chemistry, plastics, paint, printing ink, necessitates industrial classification of the substance rubber and cosmetics particularly the azo types. The dyes used in the textile finishing industries are acidic, basic, direct, mordant, IV. STRUCTURES OF DYES vat, reactive and dispense types. Others are sulphur dyes and the azo types. The acidic dyes are applied on silk,wool and nylon. They are anionic have ability to attach to the cationic group of the fibre through salt formation ( Aspland, 1997).Basic dyes are water soluble cationic dyes which contain some other dye which helps the uptake of dye on the fibre ( Longstaff, 1983).Direct and substantive dyes are used i. ACID BLACK DYE on cotton, paper, wool, silk and nylon. They are pH indicators as well. (Gregom, 1986).The mordant dyes are chemical substance which improves the fastness of the dye against water light and perspiration.The mordant dye helps to form a strong link between the fabrics and the dye, example include metal ii. BASIC RED DYE hydroxide, tannic acid, aluminum, iron and chromium. The colour of the final product depends on the dye and the mordant used, for example a piece of cloth immersed in turkey red (alizarin) is red with aluminum mordant but violet with iron mordant. Most mordant produced from heavy metals are hazardous to health and care must be taken in their applications. Vat dyes are insoluble in water and cannot be applied directly but reduction in alkaline medium produce water soluble alkaline metal salt of the dye which has affinity for textile fibre .The reactive dye as they are called have the ability to react with the fibre substrate through formation of covalent iii. VAT DYE

Likely Mechanism of Dye Adhesion on Fabrics

2 International Journal of Advances in Science Engineering and Technology, ISSN: 2321-9009, Vol-5, Iss-1, Spl. Issue-3 Mar.-2017 http://iraj.in V. FUNCTIONAL GROUPS IN DYES

iv. REACTIVE DYE

v. AZOIC DYE

VI. CLASSIFICATION OF FABRICS

Generally fabrics are classified on the basis of the origin of fibres (natural or synthetic) or its processing or its end use ( Balter, 2009). Classification on the basis of origin gives natural or synthetic fabrics. The natural fabrics are those created from the fibres of animal coats, the cocoons of vi. DIRECT RED DYE silkworms and plant seeds, leaves and stems. They do not change colours on exposure to uv light until they lose tensile strength ( Lorenzani ,1998). The synthetic fabrics on the other hand are man-made from inorganic or organic materials. They can be made to specification depending on end use condition ( Garret, 1963)

VII. FABRICS OF NATURAL ORIGIN vii. NITRO DYE (MARITUS YELLOW) The fabrics obtained from natural fibres include cotton, silk, linen, wool, leather, ramie, hemp and jute. The cotton fabric is one of the most unique of them all as it has distinctive features which makes it adjust easily with climatic conditions. It keeps body cool in summer by absorbing sweat easily and gives warmth feel in winter season. Silk is equally weather friendly and it is the strongest natural fabric which also has the quality of softness, luster, beauty and luxurious appearance. The linen, another naturally sourced fabric is considered king of natural fabric viii. MORDANT RED because of its versatility in application such as homes ix. furnishing and apparel production. Linen does not cause irritation and allergy yet, it is strong and durable. It is easily maintained by mere hand washing. The wool fabric is a weather friendly natural fabric which is soft strong and durable with excellent aesthetic value. It does not wrinkle easily and is resistance to dirt, wear and tears. The wool fabrics does not get inflame easily as it only smoulders in flame (Morgan 2005). A comfortable

x. SULPHUR RED fabric in hot and cold weather, resistant to

Likely Mechanism of Dye Adhesion on Fabrics

3 International Journal of Advances in Science Engineering and Technology, ISSN: 2321-9009, Vol-5, Iss-1, Spl. Issue-3 Mar.-2017 http://iraj.in temperature aberration is the leather fabric. It absorbs IX. STRUCTURE OF FABRICS water vapour and retains dimensional stability under stress (Kite, 2005).Other types of fibres in common The chemical structures of various fabrics are given use include; ramie,hemp and jute. below for the identification of different types of functional groups that will enhance the understanding VIII. FABRICS OF SYNTHETIC ORIGIN of dye-fabric association

These are fabrics produced by chemical processes by man through the use of petroleum as raw material. These include acetate, chiffon, acrylic, organza, lastex,nylon,velvet,polyester,taffeta,denim,rayon,geor gette,viscose,grey and polypropylene. Acetate fabrics are made from cellulose of cotton or wood pulp. It is Cellulose Fabric resistant to shrinkage, moth and dew. The fibre has soft and luxurious appearance (Kadolph,2007). The Chiffon fabrics are manufactured using silk, rayon, polyester or cotton. They are specially used for making bridal gowns, evening dresses, pron dresses and scarves. This material commands magical look on the wearer thereby exuding high personality. The Nylon 6,6 Fabric acrylic fabrics are synthetic materials used for making shirts and ladies clothes and seats for chairs. It maintains its quality for a long time because of its excellent wear and tear resistances (Koham, 1995).Organza fabric refers to a thin, plain weave fabric made from silk yarn worms, and filament fibres of nylon and polyester. They are nice to touch Wool Fabric with high degree of sophistication and uniqueness. A special type of fabric made from latex is known as lastex fabrics. They are elastic in nature and are used with other complex fibres (Dedie, 2005). Nylon fabric is synthetic materials used for clothing, shirts covers and industrial appliances. They are made Silk Fabric from the polyester of the amides obtained from petroleum (Munro,1990). Velvet fabrics are used for making trousers, shirt, bed sheets, covers and curtains. Polyester fabrics is another man-made material which has the unique qualities of wrinkle resistance and springing back to original shape. They are strong and soft materials and can be mixed with other materials such as the cotton. Taffeta fabrics are Polyester Fabric crisp, soft and smooth materials manufactured from rayon, silk or nylon. They are used for women garments. Denim is a rugged cotton material which is generally coloured with indigo dye to create blue jeans. The rayon fabric is a synthetic textile fabric which is produced by forcing a cellulose solution through fibre spinnerets. Georgette fabric is a sheer and strong silk or silk like clothing that often comes Nylon 6 Fabric with a dull creped surface. It is exquisite and unique fabric which enjoys high demand in the market. Functional Groups in Fabrics Viscose fabric material is commonly used for coating, stocking and under wears as well as staple for towels Cellulose Fabric -OH and table cloth.Grey fabric is used for cloth Wool Fabric -COOH, -NH2, -CONH- , -C=O, manufacturing due to its cost effectiveness and -NH- longevity. The material show cases aesthetics and Polyester Fabric -CH2-, -C=O, -COOR, Aromatic glamour. The polypropylene is a synthetic material Nylon 6,6 and Nylon 6 -CONH, suitable for winter season because of its ability to Silk Fabric -COOH, CONH-, -NH2, -C=O, - keep the body warm. NH-

Likely Mechanism of Dye Adhesion on Fabrics

4 International Journal of Advances in Science Engineering and Technology, ISSN: 2321-9009, Vol-5, Iss-1, Spl. Issue-3 Mar.-2017 http://iraj.in X. THE PHYSICO-CHEMICAL PRINCIPLES The interaction between acid dye and cellulose fibres OF THE MECHANISM OF DYE ADHESION is almost nonexistent, but a partial attraction is ON FABRICS proposed as follows (NOUN, 2011)

Adhesion is the ability of two different materials to stick together by material interactions and formation of chemical bonds. The process of dyeing depends not only on the type of the dye but on the type of fibre. Generally reactions between dyes and fabrics must take into account the various types of forces exerted by one material upon another. All dyeing mechanism can be divided into three broad categories (Popoola, 2015). 1. 1. Formation of specific bond between the dye and fabric owing to the covalent bond,

hydrogen bond, ionic bond dipole-dipole interaction and london forces. The formation of these bonds is dependent on the type of functional groups present in the dye and the fabrics 2. Non-specific attraction between dye and fabric owing to ion exchange or van waals forces. The oxygen of the OH group in the cellulose 3. In the absence of any interactions dyes can be adherent on fabric by physical molecule interacts with the electropositive or cationic entrapment. Na atom of the sulphonic acid group of the dye. This bond, though weak but several of it promote the The chemistry of interactions between some pairs of adhesion of the dye on the cellulose material. Another dye-fabric materials are also based on example is observed in the interaction between the electronegative oxygen atom of the cellulose and the hydrophilic/hydrophobic properties as well as the cationic Na atom of the dye molecule. Acid dyes are formation of salt linkages between dye and fabric functional group. generally applied to fibres such as silk, wool, nylon and modified acrylic fibres. Acid dye-wool 1. interaction may simply be represented by the 2. 1. Acid dye-cellulose fabric. formation of intermolecular hydrogen bonding between the H-atom of dye and the electronegative N atom of the fibre.

2. Basic Dye- Wool Fabric System

(a)

(b)

Likely Mechanism of Dye Adhesion on Fabrics

5 International Journal of Advances in Science Engineering and Technology, ISSN: 2321-9009, Vol-5, Iss-1, Spl. Issue-3 Mar.-2017 http://iraj.in 3. Reactive dye – Wool Fabric System The cellulose fabric is represented by the ROH in the mechanism. The adhesion between the dye here and the cellulosic molecule could be due to the H bonding observed between the H atom of the dye and the electronegative oxygen atom of the cellulose molecule.

8. Direct Red Dye - Cellulose System

4. Azo Dye – Wool Fabric System

In No 8 above the cellulose fabric is represented by the ROH in the mechanism. A dipole – dipole attraction between the Na atom and the Oxygen atom where non -bonding electrons are found can enhance adhesion. Several of such attractions between the two molecules proposed for the affinity of the two surfaces for each other.

5. Acid Black Dye – Cellulose 9. Reactive Dye – Cellulose Fabric Sytem

Cellulose fabric 6. Azo Dye – Cellulose System

dye – fabric system for adhesion

7. Mordant Red Dye – Cellulose Fabric System

dye adhesion with cross linking

The fibre reactive dye adhesion is due to the formation of ether linkages (R-O-R) to the OH groups of the cellulose (R-OH). The cellulose is activated by treatment with Na2CO3 base to form alkoxide (RO)

Likely Mechanism of Dye Adhesion on Fabrics

6 International Journal of Advances in Science Engineering and Technology, ISSN: 2321-9009, Vol-5, Iss-1, Spl. Issue-3 Mar.-2017 http://iraj.in groups which then attack the trianzene rings these polar groups or in many cases the formation of nucleophilically and substitute for the chlorine intermolecular hydrogen bonding, leaving groups (equation 2). The two chlorine atoms In addition to polar forces, the normal non-polar can be replaced leading to the cross linking dye- Vander Waals forces operate in dye molecule having fibre, thereby enhancing durability of the fibre aromatic nuclei where the several π electrons (Popoola, 2015) participate in the non-polar attraction. The polyesters are easily susceptible to this type of attraction. 10. Mordant Red Dye – Nylon 6 Fabric System (Popoola, 2015). A combination of these forces and physical enhancement due to compatibility promote adhesion thereby improving fastness to light, washing, bleaching, rubbing and perspiration. This in the long-run leads to maintenance of fabric quality and aesthetics.

REFERENCE

[1] Abarhart E.N (1977). Dyes and their Intermediate, New York Chemical Publisher.,PP 1-12 [2] Aspland J.P (1997). Textile Dyeing and Colouration Association of Textile Chemist and Colourist.pp2-310 [3] Balter M. (2009). “Cloth Make the (Hu) Man Science 325 [4] Dedic, Bette Jo, Potter Mike (1995). Fabric insect and Pest.Clothes Moth and Carpet Beetles. [5] Garret, Alfred (1963).The Flash of Genius Princeton. New Hydrogen bonding between the oxygen atom of the Jersey. PP 48-49 dye and the H atom of the fabric is likely to enhance [6] Gorgery P (1986). Azo Dye: Structure of Dye and Pigment. PP 45-56 adhesion between the two surfaces. [7] Kadolph, Sara J. (2007). Textile, 10thed Pearson. Pg 230 [8] Kite, Marion, Ray Thomson (2005).Conservation of Leather CONCLUSION and Related Materials Butterworth Hemenann.Pg 204 [9] Kohan, Melvin, (1995). Nylon Plastic Handbook.Hanser / Gardner Publication From the examples of dye adhesion on fabrics [10] Longsaff E. (1983). An Assessment and Categorisation on discussed in this paper, it is evident that textile Selected dyestuff. Dye and Fabric pg242-205 materials posses polar groups in large quantities [11] Lorenzani, Shirleys (1998). Natural Fibers and their which aid bonding. Some dyes adhere by chemical Composites [12] Morgan P. (2005). Carbon Fiber and their composite reaction arising from the presence of anxochromes. [13] Munro J.M (1990). Cotton, Harlow Longman Scientific and This is the case with reactive dyes where covalent Technical. New York , John Wiley. bonds are formed. The attraction of the dye for fibre [14] NOUN, (2011). National Open University of Nigeria) Study may therefore arise from the dipolar interaction of Material on Colour Chemistry and Technology, pg 57. [15] Popoola V.A. (2015). The Chemistry of Colours in Dyes and Pigments, Wits Publishing Ltd,

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