ECONOMICAL DYEING OF POLYESTER /COTTON BLENDS WITH MULTIFUNCTIONAL PROPERTY BY USING CYCLODEXTRINS
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ECONOMICAL DYEING OF POLYESTER /COTTON BLENDS WITH MULTIFUNCTIONAL PROPERTY BY USING CYCLODEXTRINS

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  • 1. ECONOMICAL DYEING OF POLYESTER /COTTON BLENDS WITH MULTIFUNCTIONAL PROPERTY BY USING CYCLODEXTRINS
  • 2. ABSTRACT The present work illustrates the beneficial effects of applying a hybrid approachwhich includes the treating of P/C blended material with pure PEG (M.wt.400), PEGsolution containing small concentration of NaOH and third one is treatment with CD afterthe later method. To realise this approach, P/C blended samples were padded in the abovementioned chemicals to wet pick up of 100% (o.w.f), and dried then subjected tosaturated steam curing in the appropriate manner. Then the dyeing is performed usingHTHP technique. The dyeing liquor was prepared using Dispersing agent, dye solutionetc.The pH of the bath was maintained at 5.5 using acetic acid. Well wetted fabric wasentered in to the dye vessel and the dyeing is performed for the prescribed time underdefinite temperature. Finally, the dyed samples were thoroughly soaped with non-ionicdetergent (3 g/l of lissapol N), rinsed and dried (for the dark shades R/C treatment wasgiven by using caustic and hydros each 1 g/l at 70 ºC). PEG & CD can be effectively used to dye P/C blends using disperse dyes only.So that it can conserve time, energy, man power etc. Nevertheless, CD plays in thefollowing roles 1) To substitute surfactants in P/C processing; 2) When bound chemicallywith fibres, it provides hydrophilicity 3) To perform easy removal of sweat and sweatdegradation products from the textiles. The successful application of disperse dyes on P/C Blend with the help of PEG& CD bring out numerous advantages such as a) Dyeing of P/C in a single stage processby using Disperse dyes only b)Saving of water, energy, time( due to single stage process)c)Replacing of conventional surfactants & thickeners by CD (It will give low BOD &COD Value than conventional one) d)Enhancement of functional property of the P/Cfabric by means of CD e)Minimizing of the effluent problem due to shortening processes,re-placing of surfactants etc f)An economical process etc
  • 3. LIST OF SYMBOLS, ABBREVIATIONS or NOMENCLATURESYMBOLS,ABBREVIATIONSor EXPLANATIONNOMENCLATUREapp ApproximatelyBIS Bureau of Indian StandardsBOD Biological Oxygen DemandCCM Computer Colour Matchingβ-CD CyclodextrinsCOD β-Chemical Oxygen Demandg/l Grammes Per LiterM.wt Molecular WeightMR Moisture RegainNaOH Sodium Hydroxideo.w.f On Weight of the FabricP/C Polyester CottonPEG Polyethylene GlycolpH A measure of Acidity or AlkalinityR/C Reduction ClearingSHPI Sodium hypophosphiteW/W Weight / Weight CHAPTER 1 INTRODUCTION The Multifunctional Auxiliaries and Energy Conservation processes are the Primeconcern of the Textile Chemical processing industry. Attempts to utilize CD in textileapplications started in the late 1980s.This was brought about by the recognition that theinclusion complex formation capability of CD can be applied to the deodorant , aroma,antimicrobial finishes that have recently popular and in treating effluents. Since thenresearch and development of CD applications have become active, and the possibilities of
  • 4. using CD in textile finishing are being explored recently in the textile industry .With thetrend in the textile industry demanding high quality and new properties, the range ofapplication of CD is expected in P/C blends dyeing. In this study, for the coloration of P/C blend fabrics, so-called disperse dyes are used, which are very poorly soluble inwater(0.1-10 mg/L).Without using solubility-enhancing agents(surfactants),uniformdyeing is not possible. CD however can replace the surfactant, and their COD in the wastewater is lower than that of the usual textile surfactants 16. With the scarcity as well as increasing prices of fuel, it has become one ofthe imperative duties of the present day researchers to cut-short the processes, withoutsacrificing the desirable properties of the product for economy in general andconservation of energy in particular. To meet the above objectiveness ,in the dyeing of P/C blends use of high boiling swelling agent like PEG can be used. In conventional processP/C dyeing involves various steps, viz. PET dyeing, reduction clearing, washing, drying;followed by cotton dyeing, washing, drying .If unfixed dyes is not removed properlyduring soaping/washing treatment will lead to poor fastness properties of the dyedmaterial .Thus ,sever washing-off treatments ,reduction clearing and intermediate dyeingsteps are involved in two bath P/C dyeing, which leads to more consumption of time,man-power ,energy and also declination in the productivity. In this study to conserve timeand energy, it is desirable to develop an economical process which can dye both theportions of the blend without altering their viz _ properties. Therefore in the presentinvestigation, an attempt can be made to dye P/C blends in a single bath with dispersedyes using high boiling swelling agent (PEG) Normal dyeing of P/C blends involves the elaborated process by usingappropriated class of dyes for PET and Cotton portion. The proposed work aims to useCyclodextrin (CD) and poly ethylene glycol(PEG) as a Pre-treatment to dye bothpolyester and cotton portion by only disperse dyes in the single stage process.Nevertheless, CD can cause some Multi functional property on the dyed fabric likehydrohilicity, anti soiling etc and the generation of COD and BOD also will be low 31compare with sodium alginate in the conventional process And use of high boilingswelling agent like PEG is desirable in P/C dyeing to develop an economical processwhich can dye both the portions of the blend in a single stage with disperse dyes so that it
  • 5. can conserve time, energy, man power etc1, 34.As on today commercially, the blends of P/C are successively dyed by two bath process using disperse dyes and cellulosic dyesrespectively. Even though one bath processes have been tried using various combinationsof cellulosic dyes along with disperse dyes, none of the processes were not successful andare not practical commercially. The successful application of disperse dyes on P/C Blend with the help of PEG &CD bring out numerous advantages such as a) Dyeing of P/C Blend in a single stageProcess by using Disperse dyes only b)Saving of water, energy, time( due to single stageprocess) c)Replacing of conventional surfactants & thickeners by CD (It will give lowBOD & COD Value than Conventional one) d)Enhancement of functional property of theP/C fabric by means of CD e)Minimizing of the effluent problem due to shorteningprocesses, re-placing of more polluting surfactants etc f) An Economical processetc.Poly-ethylene Glycol (PEG) & Cyclodextrin (CD) can be effectively used to dye P/Cblends using disperse dyes only. Which can alter the nature of polyester & cellulosicfibres contained in the P/C Blends and making it viable to dye cellulosic fibre withdisperse dyes along with hydrophobic PET. CHAPTER 2 LITERATURE OF REVIEW2.1 POLYESTER Polyester fibres are widely used in the textile field, owing to its outstandingcharacteristics, i.e., high strength, high melting point, better crease resistance, high elasticmodulus, better creep properties high wear resistance, better dimensional properties andstable for blending with other type of fibres. However, the fibres have low moistureabsorption, high static built-up, high pilling tendency and are difficult to dye under
  • 6. practical conditions due to its compact physical structure and absence of chemical activegroups etc. Extensive research has been carried out on the modification of the polymerchain to overcome some of the inherent drawback of the polyester (PET) fibres.It was reported that PET fibres desirable properties can be prepared (a) by modifying thechemical structure of the polymer during polymerization and (b) by modifying the fibresurface and the structure by treating with suitable chemical. In the first method,incorporating additives during the manufacture can modify the PET fibres. The modifying 35compounds may be mono-functional and di-functional or polymeric compounds . Atpresent this type of polyester fibres are well established commercially 33. In the secondmethod surface modification of PET fibres have been achieved using various methodssuch as alkaline hydrolysis28graft polymerization of hydrophilic monomers14, andsteaming12 Nevertheless, P/C blend enters in market because it has advantages of both PETand cellulose. P/C blend has got lot of advantages from user point of view but from dyerspoint of view it was difficult to dye the blends. And use of high boiling swelling agentlike PEG is desirable in P/C dyeing to develop an economical process which can dye boththe portions of the blend in a single stage with disperse dyes so that it can conserve time,energy, man power etc1,34 Three factors are mainly responsible for making PET fiber difficult to dye: (a)high-fiber crystallinity, (b) a marked hydrophobic character, and (c) an absence ofchemically reactive groups in the polymer. Owing to these factors, PET cannot be dyedwith the same dyes that are generally employed for cellulosic, protein, nylon, or acrylicfiber. Since the ester groups content of cellulose acetate and polyester fiber is nearly thesame (40-45%), attempts have been made to dye polyester fiber with disperse dyes by thesame method used for cellulose acetate. However, it was observed that PET was not dyedat 80-100oC. This was due to a very slow rate of diffusion of disperse dyes into thecompact polyester fiber. In the early years attention was directed to finding a means of improvingdyeability. The yield of a disperse dye on PET is limited and vastly inferior to the yield onnylon and cellulose acetate because of the low rate of dyeing rather than the low
  • 7. substantivity of early disperse dyes for PET. The problem is solved by using differentapproaches to increase the rate of dyeing.1. Building up dye molecules inside PET (azoic dyeing).2. Opening up the fiber structure to bring down the Tg (carrier dyeing).3. Using temperatures above 100°C [high-temperature (HT) dyeing].4. Heating the dye and the PET in the dry state together near the softening temperature ofthe fiber (thermosol or thermo fixation dyeing).5. Replacing water with an organic solvent as a dyeing medium (solvent dyeing). Apart from the above approaches, chemical modification of PET (to impartaffinity for dyes other than nonionic dyes is commercially practiced in order to getcationic dye able PET. Similarly, the transfer printing process is used to colour polyesterin solid shades. The use of solvents for dyeing PET is intensively investigated in the early 1970’s.Even though PET can be dyed to any depth of shade using solvents, none of the solventdyeing methods ever reached a state of a commercial feasibility. The azoic dyeing processwas once used to colour PET, but with the development of disperse dyes and variousdyeing methods; it has now lost its importance. It is now used mainly to produce blackshades.2.2 DYES FOR POLYESTER PET is now dyed with nonionic dyes specially synthesized to suit the dyeingprocesses. Nonionic dyes with low aqueous solubility at dyeing temperatures(100-130oC) are the best dyes for PET. The solubility of nonionic dyes in water is lowsuch that these dyes are considered water insoluble. It is essential; however, these dyesshould have some solubility in the dye bath to get dyed in the aqueous bath. These dyesare applied in the form of an aqueous dispersion. The small aqueous solubility and theparticle size of a disperse dye plays a vital role in the rate of dissolution and the rate of
  • 8. adsorption of dye by PET. Dispersing agents play a vital role in dyeing process. Somedisperse dyes are sensitive to heavy metals and form chelated compounds with calciumions giving tonal variations. Soft water is therefore used for dyeing. Disperse dyes are available in two forms-micro disperse granules or powder andliquid dyes. The dispersion of a dye is spray dried to get solid granules and powders. Theamount of dispersing agent required to get stable dispersions can be 40-90 % and usually60% of the dried disperse dye- powder. This large proportion of a dispersing agent in thegranules and powders of disperse dyes creates problems such as increasing aqueoussolubility, inducing migration during drying of padded goods, lowering the exhaustion ofdye bath and so on. The properties expected of micro disperse -dye granules includestability, dryness, uniformity, free flowing, non-dusting, and non-hygroscopic nature,good bulk density (app.0.5 or more), and ready dispersibility. Liquid dyes are dispersionswith a low concentration of a dispersing agent. Dispersion stability, easy miscibility,proper pH., and free flowing nature are some of the prerequisites for liquid dyes. Sincemetering pumps can be used for liquid dyes the additions, weighing and so on not poseno problems. Liquid dyes are easy to dissolve and to use. They pose none of the problemsthat arc associated with the granular dyes. However liquid dyes are likely to dry up tosettle, and to alter in concentration during storage. Special precautions are required tostore and handle liquid dyes. Many times, disperse dyes have poor storage stability,particularly, if they are exposed to a humid atmosphere. Under these conditions, thedispersion breaks into lumps. Such a dye is likely to give uneven, specky dyeing. Thestate of the dye dispersion can be easily checked by dispersing the dye in water anddropping it on filter paper. If the dispersion is good, no particle will be visible on the filterpaper. Improvements in the physical form of the dyes improve the final color results. Chemically, the disperse dyes come from various classes Such as azo,anthraquinone. Methine. and diphenylamine. The dyes usually have NO2, CN, OH,halogen and primary, secondary, and tertiary amines groups but they never have any polargroups which easily ionize in an aqueous bath. Some of the dyes have a free COOHgroup. Such dyes are usually applied by printing techniques under acidic pH so that thisgroup does not ionize substantially. Free aliphatic hydroxyl groups that impart high
  • 9. aqueous solubility are esterified with acetic acid or a mixture of acids. These dyesgenerally have low molecular weight which facilitates their entry and diffusion into thehighly crystalline polyester fiber. The higher the molecular weight of the dyes, the sloweris the diffusion in the fiber. They have significant, though low vapor pressure. Particularlyat elevated temperatures. Disperse dyes are sensitive to pH. Methine dyes hydrolyze ordimerize under alkaline conditions. The pH the dyebath for dyeing PET is thereforemaintained on the acid side. A redox buffer is usually also added to the dyebath to avoidreduction of disperse dyes 25 The fastness properties and dyeing characteristics of disperse dyes are consideredwith particular reference to the subsequent treatments. In the case of yam dyeing and. to alesser extent, piece dyeing, wet fastness after heat setting is important since the knitting orconing oils on dyed goods can lead to the migration of the dye into the oil. Besides theusual light and wash fastness, the sublimation fastness of disperse dyes is very importantsince dyes of low sublimation fastness give problems during subsequent treatments suchas resin finishing. A similar high standard of fastness is required for dry and wet rubbing.Migration of dye to the surface of the fiber during the heat-setting process frequentlyresults. Dyes with high sublimation fastness are therefore used for the dyeing of yarns.Similarly, dyes, auxiliaries and dyeing conditions are selected to give optimum coverageof small variations in dye affinity of textured yarns. Thus; dyes used for yarn dyeing mustmeet the following specifications: 1. Good dispersion properties, so that the dye is not filtered on a package of yarn that constitutes an effective filter. Paste brands of disperse dyes are usually preferred for yam dyeing. 2. Good stability in HT bath during dyeing (130°C/2 h). 3. Good leveling properties, at least with the addition of a surface-active agent. Use of certain carriers help in getting level dyeing of a yarn package. 4. Good sublimation fastness.2.3 MECHANISM OF DYEING
  • 10. The mechanism of dyeing PET with nonionic dyes under different conditions ofdyeing has some common features and some significant differences. HT dyeing andcarrier dyeing involve dye transfer from aqueous baths, while in thermo fixation dyeing;the water in the pad liquor is completely expelled by a drying process before the dye isfixed on PET. The contribution of the PET structure to the dyeing mechanism remains the same forthe three processes because the fiber does not absorb any significant amount of water andthe presence or absence of water on the fibre does not play any significant role in thesorption of dye by PET. The dye is adsorbed only in the amorphous regions of PET, thatis, it does not enter the crystalline regions. Thus, if calculated on the basis of theamorphous content of the PET materials, the fiber saturation values of a dye on differentPET materials are similar (FIG.2.1). The percentage composition of the crystalline andnon-crystalline regions in the fiber may vary from fiber to fiber and the fiber may exhibitapparent differences in its dyeing behavior. The penetration of dyes in the PET structure is explained by the free volume theoryfor the low-molecular-weight compounds in an amorphous polymer. The energy effectsin dyeing show abrupt changes over a very short range of temperatures at Tg.FIG.2.1 Temperature dependence of true saturation values of dyes on polyestermaterial.
  • 11. (a) Fixed in air oven: O: Fixed in metal press: (b). Saturation values were calculatedfor three polyesters on the basis of their amorphous content when the data on allpolyesters lie on the same plot. The concerted movements of Chain segments of polymer molecules are started at T g.An increase temperature of above Tg, raise the frequency and amplitude of the movementof chain segments. This facilities diffusion of dye and the rate of diffusion increase withthe temperature. In the thermo fixation process, however, as the thermo fixationtemperature increases and approaches the softening temperature of PET, there is suddendrop in the fiber saturation value (FIG.2.1). This is attributed to the increasedcrystallization of PET chains during the pre-melting stage, which lowers the amorphouscontent of the fiber 7 Under dyeing conditions, the rate of dye molecules on the fiber surface is alwayshigher than the rate of diffusion into the fiber. There fore, the former does not exhibit anyinfluence on the overall rate of dyeing and the diffusion of dyes within the fiber is the ratedetermining step. Disperse dye has a tendency to deposit on the fiber surface. In thecourse of dyeing, this deposited dye has to be desorbed to migrate to some other part ofthe fiber material to get the level uniform dyeing 22. This prolongs the dyeing process.
  • 12. Significant surface deposition takes place only from over saturated dye bath. 7 (FIG.2.2).This is because the surface of the polyester fiber is full of C-O-C (ether) linkages that arehydrophobic, while the C==O (ester) linkages that are hydrophilic face towards theinterior of the fiber. FIG.2.2 Dye on PET in HT dyeing (l30oC/1 h).Dye on PET in HT dyeing (l30oC/1 h). Dye: C.I. Disperse Brown I (Micro disperse).Concentration: a) 0.8 g/liter (unsaturated bath): (b)) 1.6 g/liter (over saturated bath); M:Lratio 1:4000. Since dye has to diffuse through the holes and space formed by the vibrations ofthe chain segments of PET molecules, the shape and size of the dye molecule influences
  • 13. the rate of dyeing. The higher the molecular size of dye, the higher is the space requiredfor the dye of diffuse. Because of this, as the temperature increases, the effect of the sizeof a dye molecule on the rate of dyeing decrease; that is, the activation energy of diffusionincreases with the molecular weight of the dye. The rate and extent of absorption of adye are dedicated by the fiber structure, time and temperature of aqueous dyeing orthermo fixation 9 Disperse dyes are combined to produce mixed shades. Neither therate nor the equilibrium adsorption of dyes in mixture is influenced by the presence of theother dye 8The dyes build up on PET, independent of each other, up to their saturationvalues. This is also the case with dyeing from an organic solvent 72.4 HT Dyeing The mechanism of dyeing PET with nonionic dyes in an aqueous dispersion hasbeen investigated by many workers. Earlier investigation shows that dyeing involves theattraction of positively charged particles of suspended dye to negatively charged fibersurfaces to build up a surface layer of dye particles. Subsequently, the solid dye dissolvesin the fiber to form a solid solution. This mechanism, which was first suggested for 17dyeing cellulose acetate with disperse dyes by Kartaschoff is now rejected. It is nowestablished that dyeing takes place in a saturated solution of dye in an aqueous bath thesuspended particles in dispersion form a reservoir of dye that replenishes the solution asthe dye molecules are removed from the dye bath by the fiber. The dye in solution isassumed to be in a monomeric form even though experimental difficulties prevent anyconclusive proof from being obtained on the monomolecular state of dye in solution.Disperse dyes have definite water solubility. The solubility of a dye in the bath increaseswith temperature. Dyeing takes place in three simultaneous steps: (a) dissolution of dye particles inthe bath to give a dye solution, (b) adsorption of the dissolved dye from solution on to thefiber surface, and (c) diffusion of adsorbed dye from the fiber surface to the interior of thefiber substance.
  • 14. 2.5 COTTON: Cotton is a linear cellulosic polymer. The repeating unit in the cotton polymer is Cellobiose, which consists of two glucose units. Cotton consists of about 5,000 – 10,000 cellobiose units, that is, its degree of polymerization is about 5,000 – 10,000. It is a very long, linear polymer, about 5,000 nanometer in length and about 0.8 nanometer thick. The cotton fibres are amongst the finest in common use.. Such very fine fibres permit the manufacture of fine, lightweight cotton fabrics and garments, etc,. Cotton is a very fine fibre with little variation in fibre diameter. The fibre length to breadth ratio of cotton ranges from about 6000: 1. The most important chemical group in the cotton polymer is the hydroxyl (or) – OH group. These are also present as methylol groups (or) CH2OH. Their polarity gives raise to hydrogen bonds between –OH groups of adjacent cotton polymers. Vander Wall’s forces also occur but compared with the hydrogen bonds, the van der wall’s forces are of little significance. Cotton is a crystalline fibre. Its polymer system is about 65 –70 % crystalline and about 30 – 35 % amorphous. Therefore, the cotton polymers are well oriented and probably no further apart than 0.5 nanometer, in the crystalline regions. This is the maximum distance across which hydrogen bonds can form between polymers. Hydrogen bonds are the dominant and most important force of attraction present in the polymer system of cotton. For this reason, van der wall’s forces, which are also present, have little relevance.2.6 MECHANISM OF DYEING2.6.1 The internal surface of fibers and its importance The natural fibers (i.e.,) the cellulosic and protein fibers have exceedingly large internal surfaces, which are the walls of the channels between the bundles of long chain
  • 15. molecules composing the fibre. The number of such channels is immense, of the order often million in the cross section (e.g.,) cotton or a wool fibre, and the total surface of theirwalls is of the order of 100 m2/g, (or) five acres per lb. This is about one thousand timesas large as the outer surface of the fibre. When the fiber is wetted, water rapidly penetrates and swells a large proportion ofthese channels. Dyes in solution are then able to diffuse into the channels (or) pores. They can however, enter only a relatively small proportion of the total internalspace, because the remainder is in pores too small to admit a dye molecule. Many of thesynthetic polymer fibers have much less internal surface than the natural fibres, but thedyes used with such fibers are able to penetrate between the fibre molecules even thoughwater cannot always do so. Dyes are surface active substances, (i.e.,) when dissolved in water their moleculestend to concentrate more closely together at a surface than in the body of the solution. Thesurface can be between the solutions and either air (or) a fibre. The first action in anydyeing operation is therefore the concentration of dye molecules that as much of theinternal surface of the fibre as they can reach. The concentration so produced is howevernot usually sufficient to give a usefully deep coloration to the fibre and for such colorationother factors must be brought into play. These are the chemical forces, which can operate between a dye molecule, and afibre molecule, which are classified below, and also those between the dye moleculesthemselves, which can cause their association into larger units.2.6.2 Chemical Forces Responsible For Dyeing Broadly, four main chemical effects are subsequently responsible for the substantivelyof the dye for the fibre. They are, 1. Hydrogen Bond 2. Non Polar or Wander Walls force 3. Electrostatic or ionic forces and 4. Covalent Bonds. These seldom act in isolation; usually at least two operate in any dyeing process.Additionally, the so called ‘hydrophobic bond’ may be involved.
  • 16. 2.7 Cyclodextrins: Cyclodextrins are crystalline, water soluble, cyclic, non-reducing,oligosaccharides built up from six, seven, or eight glucopyranose units. Cyclodextrinshave long been known as products, which are able to form inclusion complexes. Theyused to be, however, no more than scientific curiosities due to their limited availabilityand high price. As a result of intensive research and advances in enzyme technology,cyclodextrins and their chemically modified derivatives are now available commercially,generating a new technology: the packaging on molecular level. They have circular,conical configuration, where the height is about 800 pm and the inner diameter of thecavity is from 500-800pm. (vogtle, 1991; weber, 1987). FIG.2.3 Structure and dimensions of CD CD is a cyclic polymer of alpha-D-glucopyranose. The common cyclodextrinsused in chromatography are the alpha-, beta- and gamma-cyclodextrins which have beenshown to contain 6 (cyclo-hexamylose), 7 (cyclo-heptamylose) and 8 (cyclo-octamylose)
  • 17. glucose units, respectively. These cyclic, chiral, torus shaped macromolecules contain theD(+)-glucose residues bonded through a-(1- 4)glycosidic linkages. The most stable three dimension molecular configuration takes the form of atoroid with the upper (larger) & lower (smaller) opening of the toroid presentingsecondary and primary hydroxyl groups respectively to the solvent environment. Theinterior of the toroid is hydrophobic as a result of the electron rich environment providedin large part by glucosidic oxygen atom.FIG.2.4 Cyclic shaped CD It is the interplay of atomic (Vander walls), thermodynamic (hydrogen bonding),and solvent (hydrophobic) forces that accounts for the stable complexes that may beformed with the chemical substances which in the polar environment of the CD cavity.The complex exists in an equilibrium depended upon the concentration of the CD, theguest chemical and water.FIG. 2.5 Torus shaped CD
  • 18. Once the molecular has entered the cavity, the “goodness of fit”, as determined bythe weaker interactions taking place in the cavity, will make the final contribution to theassociation component of the equilibrium process. These week forces can create selectiveinteraction similar to those of enzymes.FIG. 2.5 Activity of CD The properties of CD enable to them to be used in a variety of different textileapplication. CD may act as a auxiliaries in washing & dyeing process. & they can also fixon to different fibre surfaces. Owing to the complexing abilities of CD, textile with thefunctional properties to be prepared this project aim is to cross link CD molecules onhydroxyl groups of PEG & cellulose via BTCA4CD are macro cyclic compounds builtfrom glucopyranose units linked by α ( 1,4)-glycosidic bonds (frendenberg, 1948;vogtie, 1991). CD can be obtained by enzymatic degradation of starch. In this processcompounds with 6-12 glucopyranose units per ring are produced. Depending on enzymesand how the reaction is controlled the main product is, α, β or γ, cyclodextrine (6, 7 & 8glucopyranose units respectively). β- CD is the most commercial interesting of the threenatural CD because of the easy production, availability, cavity diameter and price. It ismost widely used and presents at least 95% of all produced and consumed CD (Szejtli,1994), the inner diameter of β-CD cavity is from 600-680 pm (Szejtli, 1996;Jozwiakowski, 1985) and can accommodate aromatic compounds such as volatilemolecules and pharmaceutical compounds. New concept for modification of textilesubstrate is based on the permanent fixation of super molecular compounds, such as CDon the material surface and thus imparts new functionality to the fabric(Knittel,2003).In
  • 19. such a way that treated substrates will be important for medical and hygienic textiles forgarment and home textiles( Buschmann,1990). From the structure of β-CD it is evidentthat it can not form direct co-valent bond with textile fibres.Polycarboxylic acids like1,2,3,4 BTCA are well Non-Formaldehyde Cross Linking Agent, which can react withOH group of PEG & Cellulose and form stable ester bonds (Lewis, 1997; Yang, 1991;Martel,2002). Molecules, or functional groups of molecules being less hydrophilic than water,can be included in the cyclodextrin cavity in the presence of water, if their moleculardimensions correspond to those of the cyclodextrin cavity. The formed inclusioncomplexes are relatively stable and rapidly separate from the solution in crystalline form.One, two or three CD molecules contain one or more entrapped guest molecules. This isthe essence of molecular encapsulation, the packaging on molecular level. Molecules ofpoorly soluble drugs, rapidly deteriorating flavors, volatile fragrances, toxic pesticides ordangerous explosives, even gases can be encapsulated. The capsules of molecular size arethe cyclodextrins. Almost all applications of cyclodextrins involve complexation. In manycases complexes are separated in more or less pure form and utilized as crystallinesubstances (drug and flavor complexes) while in other cases the complexation process isonly a transient state, and becomes apparent through the final result(CD-catalysis,separation of mixtures.) Up to quite recently cyclodextrins have been considered exclusively as “empty”capsules of molecular size. Recent studies revealed such a broad versatility in theirapplication, that they can be considered as a new group of industrial basic materials. CDsare besides being “molecular capsules”, reagents in analytical chemistry and diagnostics,raw materials for the production of derivatives and polymers, biologically activesubstances, etc.Research Objective of this Project:
  • 20. To dye P/C in single stage process by using Disperse dyes To save water, energy, time due to single stage process To replace the surfactant & alginate by CD to face BOD, COD Problem To enhance the functional property of the P/C fabric To minimize effluent problem due to shortening processesEXPERIMENTAL METHODOLOGYMATERIALS: Fabric: 67:33 Polyester: Cotton Knitted Sample.
  • 21. Yarn: 67:33 and 50:50 Polyester: Cotton Blended Samples. Dye stuff: Yellow C4G H/C N.Blue 3G 200% Scarlet BR Special Auxiliaries: β-Cyclodextrin Polyethylene glycol with m.w 400 BTCA Sodium Hypophosphite And all other chemicals are in laboratory reagent gradeMETHODS:Scouring and Bleaching: The samples were scoured and bleached by the Combined Process at 80 ºC for 45min., with a solution containing 2 gpl Non-Ionic Detergent, 2 % Hydrogen Peroxide and 2% sodium carbonate etc, Washed with Hot Water, Cold Water, Squeezed and Air Dried.Chemical Treatments: Table Methods Treatment
  • 22. U Untreated A Samples Treated with PEG then steaming at 160º C for 2 min. Finally the samples were thoroughly washed with tap water and air dried. B Samples Treated with a mixture of PEG and Sodium hydroxide solution (95.5%/4.5% w/w) to wet pick-up of 100 % expression then steaming at 160º C for 2 min.Finally the samples were thoroughly washed with tap water and air dried. C Samples Treated with a mixture of PEG and Sodium hydroxide solution (95.5%/4.5% w/w) to wet pick-up of 100 % expression then steaming at 160º C for 2 min ; treated with CD in different concentration(10,15,20,30,35gpl) along with BTCA-0.6% ,Catalyst- SHPI-0.6% etc then Curing at 170º C for 2 min . Finally the samples were thoroughly washed with cold water and hot water, air dried.Dyeing: All the dyeing was performed using HTHP Dyeing technique. The pH of theliquor was maintained at 5.5 using acetic acid. Well wetted fabric was entered in to thevessel with the disperse dyes-x%, dispersing agent-0.5% etc at room temperature and thenthe temperature is gradually raised to 130ºC and work for 30-40 min .Finally, all the dyedsamples were thoroughly rinsed, soaped with 3 gpl Lissapol N(Non-ionic detergent) atboil for 10 min, washed and air dried. CHAPTER – 42.3. Testing and Analysis:2.3.1 Determination of degradation of PET:
  • 23. Carboxylic content of treated samples (A, B & C) was analyzed according to areported method10.This tests is useful to determine the degradation effect of PET causesby alkaline and steaming, However the staining test can also carried out with Basic dyes(Basic Blue 9 for 0.5%(o.w.f); Temp. 85ºC, Time, 60 min; MLR 1:100) to findqualitatively through colour strength determination by CCM.2.3.2 Dye Exhaustion percentage: The dye uptake was evaluated by visible spectroscopy from calibration curve ofconcentration versus absorption of the individual dye at its wavelength of maximumabsorption using shimadzu spectrophotometer. Dye exhaustion percent expressed as E%,it was calculated as a difference between the dye concentration before and after dyeing.i.e. E %=( Cb-Ca/Cb) x 100---------- (2.1) Where, E-Exhaustion percentage Cb-The Dye concentration before dyeing Ca- The Dye concentration after dyeing2.3.3. Evaluation of K/S Value: Colour strength (K/S Value) of the dyed sample was measured on Data Spectraflash SF 600 Sectrophotometer.These values are computer calculated from reflectancedata according to kubelka-munk equation2 K/S= (1-R) ² / 2R---------------- (2.2) Where-Light absorption co-efficient S-Light scattering co-efficient R- Reflectance of the dyed samples2.3.4 Fastness Properties:
  • 24. The fastness properties of all treated and untreated dyed samples to washing,Rubbing and sublimation were assessed according to BIS Test methods (Bureau ofIndian Standards).The change in shade was visualized using grey scale and graded from1 to 5, 1 indicates poor and 5 indicates excellent fastness properties (Light fastness weregraded from 1 to 8, 1 indicates poor and 8 indicates excellent fastness to light) 62.3.5 Surface Studies: The surface of untreated and untreated samples were studied using SEM analysis,the samples was mounted on a standard specimen stub and examined in a Jeol jxa-84 ohElectron probe micro analyzer, Japan operating at 19 KV. A Thin Coating ( app. 10 nm )of gold was deposited on to the sample and attached to the stub , prior to examination inthe SEM , to enhance conductivity and secondary electron emission characteristics of theover growth .2.3.6 Determination of Moisture Regain:: The alternative current (a.c.) electrical properties is very much useful to determinethe moisture regain of both treated and un-treated samples, which have been studied usinga programmable automatic RCI bridge (PH 6304 Philips), analyzing their dependence ontemperature and frequency. The a.c conductivity and electrical resistance have beenmeasured in the frequency range (5-20 KHz) over the temperature (24-100ºC).Sampleswere in the form of tablets and silver rods was used as electrodes. Sample temperaturewas measured using a pre-calibrated chromelalumel thermocouple type K placed near thesample. All measurements were carried out in specially designed cell.2.3.7 X-Ray Diffraction: Both treated and untreated samples were investigated by X-Ray diffractiontechnique using Siemens D-5000(Computer controller) X-ray diffract meter, with Cutarget (1=1.542 Aº) and Ni filter. A continuous scan mode was used to scan 5 º <20> 65in 0.05 step. The samples were in powder form.
  • 25. 2.3.8 Wettability : A Simple test of Wettability of fabric is to cut small square specimens, ex.1 “x 1“., and to drop them on to the surface of a beaker of distilled water .The time takenfor the specimens to make sink below the surface is observed , the shorter the time thegreater the wettability52.3.9 Soil Release Testing: The tumbler test is used with the help of artificial soil to find out Soil Release 18property of both treated and untreated samples. (See Annexure). The fabric sampleswere soiled by using ISI procedure involving repeated (thrice) dipping of fabric instandard soil, padding and drying. Standard soil contained coconut oil, fatty acid, whiteoil, carbon black in tetrchloroethylene solvent. Soiled samples were soaped at 95ºC for 10min in nonionic detergent (4 gpl) followed by washing with distilled water. The soiled aswell as washed samples were visually compared to assess the extent of soil removal andgraded21 .2.3.10 Pilling Tendency: ASTM has recommended different test Methods for determining pilling resistanceand other surface effects such as fuzzing. Accelerator test methods were used for pillingtendency testing and it covers the method for using the impeller tumble abrasion testingmachine to evaluate the pilling propensity of knitted fabric32 .The Grading of pilling aregiven in ANNEXURE
  • 26. CHAPTER 5 RESULTS AND DISCUSSION Polyethylene Glycols are widely used in textile in processing as additives forimproving fixation of disperse dyes to specific fibre type. For example , cellulosic andcellulosic fibre blends exhibit improved dye ability when concentrations of up to 10% 26PEG(av. M.w of 100-600) were used in the dye bath Similar improvements wereobserved when PEG was used as dye bath additives in the dyeing of P/C fabrics withdisperse dye 20 . Cyclodextrins can be considered as a new class of Textile auxiliary’s substancesfor the textile Chemical processing industry; Very important is that their COD in thewaste water is lower than that of the usual textile auxiliaries. While the COD is 2020 mg/g for NP-10(a polyester); 1930 mg/g for Uniperol O (a fatty alcohol polyglycol ether;BASF), for β-CD this value is only 1060 mg/g 19 . For coloration of PET fibres , so- calleddisperse dyes are used, which are very poorly soluble in water(0.1-10 mg/L) Withoutusing solubility-enhancing agents(surfactants), uniform dyeing is not possible . CD,however, can replace the surfactant24.A New finish was developed for easy removal ofsweat degradation products from the textile by preventing their penetration into the fibre .A Cotton textile was impregnated with a composition containing dimethylolethylene urea,catalyst and β-CD (5-50 gpl) and fixed. The textile was treated with in a bath containing10 gpl butyric acid and as the concentration of β-CD increased in the finish bath , theconcentration of butyric acid in the fabric increased 30 This project’s intention was to make the use of the positive aspects of thementioned methods for modifying the surface of the fabrics and we choose to apply ahybrid approach. The influence of the type of treatments, carboxylic content, dye uptake,Surface topography, fastness properties, electrical properties and the structural propertiesof the treated and untreated samples are discussed below.
  • 27. Table-1: Carboxylic Content & Colour Strength of Various treated Samples ofCarbonized P/C Fabrics Dyed With Basic Dyes. Carbonized P/C Carboxylic content m.eq.100 gr.fabric Colour Sample Strength (K/S) Untreated 31.2 0.23 A 48.4 0.29 B 290.6 2.54 C 180 2.2 It is seen from Table -1, that the carboxylic content in the case of treated sample ishigher than the un-treated ones; and that the mode of increasing is depending upon thetype of treatment. The hydrolysis of polyester takes place not only at their free ends, butalso in other positions, thereby the increase in carboxylic content was continued andreached 290.6 m.eq./100 gr.treated samples. The colour strength of samples dyed withbasic dye is thus indication of hydrolysation and it can provide an assessment of thedegree of hydrolysis. It was found that K/S increased as the concentration of carboxylicgroups increased, even though the concentration of the basic dye in dyeing bath was heldconstant. On the other hand it was found that the values of carboxylic contents havedecreased and it might be possible that the action of PEG is more chemical in nature. Thenew formed free carboxylic end groups react with hydroxyl groups in PEG and CDthereby decreasing its content and forming the block copolymer of PET and PEG[Block A][Block B][Block A][Block B] and Grafting with CDWhere, Block A- PET Block A- PEGConversion of Carboxylic groups to Carboxylate Anion: When fabrics were treated with BTCA & CD, esterification between BTCA,CDand hydroxyl group of cellulose & PEG occurred at elevated temperature . After washing
  • 28. the un-reacted acid, the carbonyls retained in the fabrics and existed in three forms,namely Ester, Carboxylic acids and Carboxylate anions The formation of such block co-polymer is well established3.Nevertheless, ADistinct feature of CD is its ability to form inclusion compounds, where inclusionformation is mainly affected by the geometric shape of the molecular rather than chemicalinteractions. The hydrophobic portion of the guest molecule is positioned such thatmaximum contact with the non-polar cavity is possible while the hydrophilic portion islocated on the outer surface of the inclusion complex such that it is near the proximity ofthe hydroxyl groups of the host 23Grafting of β-CD on to OH group via BTCAThe proposed Grafting reaction of β-CD on to OH group via BTCA
  • 29. Qualitative Determination of β-CD Molecules on the Textile Substrates β-CD Molecules on textile substrate was determined by phenol Red andPhenolphthalein. Phenol red forms coloured complex with β-CD, So, phenol red changescolour from red to yellow when CD is present on the substrate.Fig-3Change of phenol red colour from red( for untreated) to yellow for treated in solutioncontaining 30 gpl of β-CD, 6 gpl of BTCA , 6 gpl of SHPI; Thermofixed and rinsed incold water and washed at 60ºC for 30 min.
  • 30. Figure – 4 presents the change in the colour of phenolphthalein from carmine redfor untreated textile substrate to colourlessFig-4Change of phenolphthalein colour from carmine red( for untreated) to colour less for thefabrics treated in solution containing 30 gpl of β-CD, 6 gpl of BTCA , 6 gpl of SHPI;Thermofixed and rinsed in cold water and washed at 60ºC for 30 min.Dyeing Properties: The probable reason for these observations may be explained as follows: The twocomponents viz. cotton and polyester, present in the blend possess differentcharacteristics individually. Cotton fibre constitute of a continuous network of cellulosechain which come together at certain places to form an ordered arrangements calledcrystallite or miscelle.The size of the spaces between the micelles in the water swollenfibre covers the maximum size of molecule which can penetrate into the closely packedstructure of the micelles. The pore size available in cellulosic molecule is much highercompared to disperse dyes which are usually small molecular weight compounds .Thus toand free movement of dye particle occurs without any sort of disruption from the dyeliquor to the fibre and vice versa .Due to this virtually no dyeing results .However, thepore size in the fibre structure probably reduces in the presence of PEG, thereby allowing
  • 31. dyeing to occur. On the other hand, the compact structure of polyester allows minimumpore size available for the penetration of dye molecule. It is well established that forpolyester, penetration of disperse dyes is more prominent at higher temperature due tomore availability of free volume18.In the present study, the presence of PEG hinders theusual penetration of the dye molecules.Effect of. CD’s conc. on Dye exhaustion (E %) and Colour strength (K/S) of treatedand untreated P/C Blends dyed with Disperse dyes CD C Conc. (gpl). E% K/S 0 24 2.4 10 37.8 4.2 15 44.2 4.8 20 48.2 4.2 30 52.5 5.2 35 52.1 5.2Effect of. Treatments on Dye exhaustion (E %) and Colour strength (K/S) of treatedand untreated P/C Blends dyed with Disperse dyesUntreated A B C*E% K/S E% K/S E% K/S E% K/S24 2.4 29.4 2.9 61.9 4.4 64.5 6.2*30 gpl of CD Treatment The dye exhaustion and colour strength increases by increasing the Conc., of CDup to 30 gpl then the effect gets no change due to saturation. The type of treatment alsodetermines the dye exhaustion and colour strength that means the alkaline and PEG
  • 32. treatment alter the characteristics of fibre. The swelling of PET fabric is favored atsteaming temperature, thus facilitating the diffusion of saturated steam inside the fabricthereby speeding the removing of oligomers, opening up and modifying the fabricstructure, as well as enhancing the segmental mobility, this speeds the diffusion of the dyein to the fabric and increases its dye uptake29. In case of P/C blend ,the presence of PEG, the K/S Value is more for cottoncomponent and less for polyester component , & it is possible that the pore size availablein the cotton fibre structure reduces in the presence of PEG thereby making the cottonfibre as dyeable with disperse dyes1Surface Topography: The Surface of untreated and treated samples was studied using SEM analysistechnique. Photomicrographs corresponding to different investigated samples are depictedin the following figures.Fig-2 SEM for the surfaces of untreated sampleFig-3 SEM for the surfaces of Samples Treated with PEG then steaming
  • 33. Fig-4 SEM for the surface of Samples Treated with a mixture of PEG and Sodiumhydroxide solution (95.5%/4.5% w/w) to wet pick-up of 100 % expression thensteamingFig-5 SEM for the surface of Samples Treated with a mixture of PEG and Sodiumhydroxide solution (95.5%/4.5% w/w) to wet pick-up of 100 % expression thensteaming at 160º C for 2 min ; treated with CD then curing at 170º C for 2 min The untreated sample has a smooth surface (Fig-1). When these samples weretreated with PEG & steam the surface becomes less coarse (Fig-1). On the other hand thesurface of sample treated with sodium hydroxide and subjected to steam have changedvery unevenly , the fabric becomes coarser with pits and pores as shown in (Fig-3) .Aftertreatment with the alkaline PEG, CD the surface of the sample becomes much coarsercompared with other samples(Fig-4). This indicates that sensitive presumably amorphousareas are susceptible to attack. The above mentioned surface observation is in fullagreement with the results listed in table of Colour strength analysis.Fastness Properties: Fastness properties of treated and untreated samples are shown in Table-4.It isclear that the present treatments improve the sublimation fastness property with high levelrather than light and washing fastness since the water loving groups like hydroxyl,Carboxyl group etc will enhance the sublimation fastness property in the dyed material.Nevertheless, the fastness property of the given dyed material is mainly depends uponthe percent blend proportion that means the given treatment produce good fastnessproperty if the PET portion is more. The washing and Rubbing fastness get minimized ifthe depth of shade gets increased.
  • 34. Table-4 Fastness properties of Treated and untreated samples dyed with Dispersedyes* Fastness Grades for 67:33 Blends 50:50 Blends Light Medium Dark Light Medium Dark W R S W R S W R S W R S W R S W R SU 3 3 3 3 3 3 3/2 2 3 4 4/3 4/3 4/3 4/3 4/3 2 3 3A 3 3 4/3 3 3 4/3 3 3 4 4 4/3 4 4 4 4/3 3/2 3 4/3B 4 4/3 4/3 4 4/3 4/3 4/3 4/3 4 4 4/3 4 4/3 4/3 4 3/2 4/3 4C 4 4 4 4 4 4 4 4/3 4 4 4/3 4 4/3 4/3 4 3/2 4/3 4*Samples (U-Untreated; A, B and C Treated) Where, W- Wash fastness; R-Rubbing fastness; S-Sublimation fastness; U-UntreatedsampleMoisture Regain: The moisture regain of treated and untreated samples was determined. It wasfound that treatments under investigation are accompanied by an increase in the moistureregain. The most pronounced effect is obtained in case of treatment C and D.This couldbe due to the outstanding increase in carboxylic contents and hydroxyl groups after suchtreatment and out of which sample D has more moisture regain than others due tocarboxylic content and free hydroxyl group present in the CD Structure. Table-5 Moisture Regain of Treated and Un-treated sample Samples Moisture Regain (%) Untreated 0.42 A 0.96
  • 35. B 1.33 C 1.52 D 1.71X-Ray Investigation: The X-Ray diffraction patterns for treated and untreated samples are shown inFig-6. X-ray Diffraction Patterns It is seen that all patterns have the same three peaks at 20 of 17.8º, 23.2º and 26.5ºrespectively. These three peaks correspond to the 010,110,100 spacing. This indicates thatall such samples have the same triclinic unit cell with interplaner spacing, very close tothat previously reported36 Table-6: D-spacing and Crystallinity of treated and untreated samples Samples D-spacing Crystallinity 010 110 100 (%) Untreated 5.11 3.989 3.52 24.1 A 5.257 - 3.39 25.9 B 5.10 3.93 3.54 32 C 5.133 3.9 3.50 27.7
  • 36. Table-6 indicates the measured interplaner spacing for all the samples, whereminor changes in these values were observed. These values fluctuate depending on thetype of treatment .It was found that the untreated sample contains 24.1% crystalline area.The treated samples with PEG with alkaline solution and CD contain 25.9 and 27.7 %respectively, crystalline area. So, structurally, i.e. ., in terms of the total crystalline area,there is no much significant change. Thus, it can be assumed that, upon treatment withPEG and with its alkaline solution before CD treatment, the overall crystalline areasremain the same. It seems that the treatment with treatment with PEG and sodiumhyadroxide increases the degree of crystallinity; a point that contradicts with dyeingproperties and MR of modified samples (Table-colour strength & Regain). As thecrystallinity increases, the dye uptake also increases. Such contradiction would nothappen if we consider the crystallite size. Increase of the colour strength with increasingthe crystallinity confirms that a change in the crystallite size has occurred under thepresent treatment condition13Correspondingly the amorphous regions accessible to the dyemolecules increases due to the decrease of crystallite parts.Electrical Properties: The electrical resistance R(w) and a.c.conductivity sa.c(w cm) power -1 for all thesamples were measured in temperature 24-100ºC and at one frequency ( 20 K Hz) .Variation of the R and sa.c values with change in the type of treatment is given in Table-7Table-7 Electrical resistance R (w) and a.c Conductivity s a.c (w cm) power-1 of thetreated and untreated samples. Property Temp. Untreated A B C
  • 37. ** 24 1.7 0.9 1.8 0.8 60 1.7 0.6 1.6 0.6 Rx10 8 100 1.6 0.4 1.3 0.4 w 24 7.2 13 9 16 60 7 23 9.4 26 S a.cx10 -10 100 7.7 28 11.2 36 (W cm) -1 ** Measuring was carried out at one frequency (20 KHz) Based on the obtained data, one could conclude the following: a) a slight decreasein R and a little increase in s a.c values takes place after treatment with NaOH solution inspite of the significant increase in moisture regain of the sample b) Changes in the valuesof both R and s a.c are more pronounced in the case of sample C.Such treatmentssignificantly decrease R (2-4 times) and markedly increases s a.c ( 2-5 times) values, ascompared with those for untreated samples , and illustrates the positive effect oftreatments with PEG on the electrical properties of Sample. This result postulates theamount of MR increasing after treatment with PEG and CD through resistance andconductivity changes phenomenon.Wettability: Wettability of sample was measured by noting the time of sinking for a 5x5 cmpiece under constant weight in distilled water21. The Table-8 shows the different wettingtime for different type of treatments. Here, the water absorbing groups like carboxylic,hydroxyl etc increase the wettability of the samples rather than untreated one. Both PEGand CD having hydroxyl groups in their structure and these groups cause morehydrophilicity.However, the wettability and hydrophilicity is also depends on the percent
  • 38. proportion of cotton portion. Generally, the water absorbing groups increases thewettability of the material, it was known by comparing the different sinking time for thedifferent treated samples. If the sinking time is low the wettability will be more and so on. Table-8 Wettability of treated and untreated samples Wetting Time( Sec) Polyester P/C Samples 67:33 50:50 Untreated 48 28 16 A 30 13 10 B 12 5 4 C 4 3 2 The effect of caustic treatment on both PET and cotton is positive in nature withrespect to wettability. The reaction of caustic on PET is takes in place in the followingmanner according to specific time, temperature, concentration etc.Effect of Caustic on Polyester O O O C H 2 -C H 2 -O -C 2NaOH O O N a -O -C Sodium Terephthalate Ethylene GlycolSoil Release Testing:
  • 39. The polyester fabrics show a higher extent of soiling than P/C samples. However,in both cases alkali treatment and PEG treatment leads to improvement in soil removalcharacteristics. When the sample is treated with PEG and NaOH, dried and baked, someester interchange between teraphthalate sodium polyglycol oxide takes place andhydrophilic grafts-COO (CH2CH2O) n H-are formed on the fibre. The treatment shows animprovement in soil release and re-deposition properties as well as a drop in static chargeseven after treating with CD27, 18. And When CD bound chemically with fibres, it providesenhanced hydrophilicity, it performs easy removal of sweat and sweat degradationProducts from the textiles, since the CD will not allows the degraded compounds in to thecore of the fibre16.However, the soiling also depends on static charge generation propertyand the percent proportion of hydrophilic fibre present in the blended fabric.Table-9 Soil Release Property of treated and untreated samples Soil Removal (Grade) Polyester P/C Samples 67:33 50:50 Untreated C B B A B A-B B B A-B A A-B C A A APilling Tendency:
  • 40. Synthetic fibres are easily brought to surface of the fabric than cellulosics, becauseof their smooth surface and circular cross-section. Due to their higher mechanical strengthand abrasion resistance, the pills remain for a longer time 21. The Pilling tendencydepends on the type of fibre in the fabric (see annexure). The treatment with the causticsoda solution weakens the polyester fibres resulting reduction in the pilling tendency.Fig- Effect of Caustic on Polyester O O O C H 2 -C H 2 -O -C 2NaOH O O N a -O -C Sodium Terephthalate Ethylene Glycol In the caustic treatment, the polyester is hydrolyzed to produce water soluble sodiumterephthalate and ethylene glycol resulting decrease in tenacity will takes place and itproduce low pilling tendency formation . Although, pilling may be de-aggravated by reducing electrostatic pick up of tint,dirt, or other foreign matter due to making the fibre as more moisture regain andhydrophilicity.Table-10 Pilling Grade of treated and untreated samples Pilling Grade Polyester P/C Samples 67:33 50:50 Untreated 2 3-2 3 A 2 3 3-2 B 2-3 4-3 4
  • 41. C 4 5-4 5-4 CHAPTER 6 CONCLUSION & SUGGESTIONS Disperse dyes do not posses any affinity for the cotton component of the P/CBlend when applied using conventional dyeing techniques. Further, tone-in-tone effect onsuch blends can not be achieved by using only one dye in a single dye bath application.This can be readily done by treating with PEG, NaOH, and CD etc. Nevertheless; CDimproves the other functional properties like Soil release, hydrophlicity, Crease recoveryalso (since the BTCA is used in CD Treatment, Which is an non-formaldehyde crosslinking agent). These compounds improves the dye ability of disperse dyes on P/CBlended fabric. The fastness properties are also slightly improved due to the presence ofPEG and CD. The successful application of disperse dyes on P/C Blend with the help of PEG &CD bring out numerous advantages such as, a) Dyeing of P/C in a single stage process by using Disperse dyes only b) Saving of water, energy, time (due to single stage process)
  • 42. c) Replacing of conventional surfactants & thickeners by CD (It will give low BOD & COD Value than conventional one) e) Enhancement of functional property of the P/C fabric by means of CD f) Minimizing of the effluent problem due to shortening processes, re-placing of Surfactants etc g) Which is an Economical process since it saves time, cost etcCYCLODEXTRIN might play a significant role in the dyeing of P/C blends and might be used  Substitute for conventional Surfactants in P/C processing;  When bound chemically with fibres, it provides enhanced hydrophilicity  It perform easy removal of sweat and sweat degradation Products from the textilesAPPENDICESAppendix 1Effect of NaOH on polyester during Alkali Treatment21.Treatment Polyester P/C(67:33)Concentration Time Wt.loss Weft Wt.loss Weft(%) (min) (%) strength (%) strength (Kg) (Kg)0 0 0 72.5 0 36.50.5 15 <1% 72 <1% 360.5 30 <1% 72 <1% 361 15 <1% 72 <1% 361 30 <1% 71.5 <1% 35.5Appendix 2Modification in Properties on Alkaline Treatment21
  • 43. Treatment Polyester P/C(67:33)Concentration Time Wetting Soil Wetting Soil(%) (min) time Removal time Removal (Sec) (Grade) (Sec) (Grade)0 0 48 C 28 B0.5 15 - B 6.5 A-B0.5 30 8.5 A 4.0 A1 15 2.5 B 2.5 A-B1 30 2.0 A 1.5 AA- Good soil Removal, B-Moderate soil removal, and C-Poor soil removalAppendix 3 Composition of Artificial soil18 Ingredients Amount % Peat moss 38 Cement 17 Kaolin clay 17 Silica 17 Carbon Black 1.75 Red iron-oxide pigment 0.5 Mineral oil 8.75Appendix 4Typical pill curves for common textile fibres18
  • 44. Appendix 4 Pilling Grades* Rating Description Points have been considered 5 No Change No visual change 4 Slight Change Slight surface fuzzing 3 Moderate Change Isolated fully formed pills 2 Significant Change Distinct fuzzing 1 Sever Change Dense fuzzing * (Physical Testing of Textile by B.P.Saville, published by Textile Institute, 2000, pp 191
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