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.