The sensitivity and impact of dye structure and fibre micronaire on the increased dyeability of bioengineered cotton fibres

Previous research reported on a screening method to assess the functionalisation of bioengineered cotton fibres through the absorption of CI Acid Orange 7. The aim of the present paper is to extend this study to different dye classes. Thus the dye absorption of bioengineered cotton fibres containing oligochitin is studied for a series of dye classes. Statistically significant differences were found between cotton lines designed to produce oligochitin in the fibre and their respective controls for all tested dyes, confirming previous results with CI Acid Orange 7. Further, although variations in micronaire influenced dye absorption, it was confirmed for all dyes tested as well as for CI Acid Orange 7 that the oligochitin production had a larger impact on the exhaustion values than the differences in micronaire. The method described in this paper can be applied as a screening tool to meet the challenge of working with small quantities of fibrous materials. Moreover it shows the potential that the incorporated oligochitin has for increasing dyeability with a wide range of dyes and creating fibres with more versatile reactivity.     

Modified polyurethane with improvement of acid dye dyeability

This article concerns the modification of polyurethane using polyamide 6,6 prepolymer to improve the dyeability properties of the polyurethane copolymer with acid dye. First, the carboxyl‐terminated polyamide 6,6 prepolymer was synthesized from adipic acid and 1,6‐diaminohexane. The isocyanate‐terminated polyurethane prepolymer was also synthesized from polytetramethylene glycol and 4,4′‐diphenylmethane diisocyanate in N,N‐dimethylformamide. The polyurethane prepolymer was then extended with a mixture of 1,4‐butanediol and the polyamide 6,6 prepolymer (molar ratios of 1,4‐butanediol to prepolymer being 100%, 75%, 50%, and 25%, respectively). Finally, the poly(urethane–amide) copolymers were dyed with acid dyes. The chemical, physical, and the dyeing properties of the poly(urethane–amide) coploymers are discussed. From the experimental results, it is found that the inherent viscosity of poly(urethane–amide) coploymers is increased with the increasing amount of polyamide content. The structure is proven by infrared spectra, which exhibits the absorption peaks of urethane and amide groups as we expected. From the differential scanning calorimetry measurements, it is found that the poly(urethane–amide) coploymers have two‐phase structures and good phase separation. There are four transition temperatures (T_gs, T_gh, T_ms, and T_mh), but only those copolymers in PTMG 2,000 series possess T_ms. Moreover, the T_gs is found to change with the length of soft segment, and the T_gh is increased with the increasing amount of polyamide content. Also, the dyed copolymers exhibit higher T_gh than those without dyeing of dye molecule, but the T_gs is not obviously changed. For mechanical properties, it is indicated that both the modulus and the strength of the coploymers are higher than those of unmodified polyurethane, but they are lowered after being dyed with dye molecule due to further separation of intermolecular distance of the dyed polyurethanes. For dye uptake in dyeing properties, it is found to increase with increasing amount of polyamide content. For dye fastness, the dyed copolymers exhibit higher grade of water fastness than that of unmodified polyurethane. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1397–1404, 2003     

Chemical modification of cotton to improve fibre dyeability

A new fibre-reactive quaternary compound containing an acrylamide residue was synthesised and used as a cotton modification reagent. The agent was applied to cotton fabrics using a pad-bake process. It was found that the treated fibre could be dyed with reactive dyes without the addition of salt or alkali. The reactive dyes were almost completely exhausted and showed a high degree of covalent bonding with the pretreated cellulose. The effect of varying the pretreatment conditions was investigated and the optimum conditions for pretreating and dyeing were established.     

Factors affecting the dyeability of cotton crosslinked with polycarboxylic acid

Improved dyeing properties of cotton crosslinked with polycarboxylic acids are produced by addition of reactive nitrogenous additives, such as alkanolamines and hydroxyalkyl quaternary ammonium salts, to the treatment formulation. Both N-methylolamides and polycarboxylic acids are effective for crosslinking cotton and bonding reactive nitrogenous additives to the cellulosic substrate, but dyeing characteristics of the finished fabrics are very different. In this study, the influence of the reactive additives and dyebath pH on the colour yields of cotton crosslinked with polycarboxylic acids and then dyed with anionic dyes were determined. Emphasis is on the dyeing properties of cotton finished with 1,2,3,4-butanetetracarboxylic acid or citric acid non-formaldehyde crosslinking agents, and alkanolamine hydrochloride or hydroxyalkyl quaternary ammonium salt additives.     

Reactive dye dyeability of cellulose fibers with cellulase treatment

Peel strength and lap shear strength between aluminum and polyimide were measured at different imidization temperatures. Polyimide was synthesized from 3,3′,4,4′-benzophe-nonetetracarboxylic dianhydride (BTDA) and 4,4′-diaminophenylether (ODA). The interfacial adhesion between polyimide and aluminum shows a maximum value at the imidization temperature of 320°C. To relate the intefacial adhesion strength with chemical interaction between polyimide and aluminum the Fourie, transform infrared spectroscopy (FTIR) ATR technique was used. In addition, morphological studies on the peeled surfaces were also carried out. © 1996 John Wiley & Sons, Inc.     

Reactive dye dyeability of cellulose fibers with cellulase treatment

Reactive dye dyeing was performed on cellulose fibers in combination with cellulase treatment. First, polynosic and cupra fibers were selected to discuss the saturation dye uptake of the previously cellulase-treated fibers. Cupra fiber exhibited a similar saturation dyeuptake dependence on weight loss, irrespective of dye species and the substantivity of the dyes. In the polynosic fiber, the saturation dye-uptake dependence on weight loss exhibited a minimum using a lower substantive dye and a maximum using a higher substantive dye. Comparative discussions of the saturation dye uptake based on X-ray and infrared measurements led to the assumption that a region dyeable with the higher substantive dye is created by the cellulase treatment of the polynosic fiber. This region is assumed to have some degree of order as shown by infrared spectroscopy. Next, cotton fiber, which is important from a practical viewpoint, is dyed and then hydrolyzed. It was found that the hydrolysis of cotton fiber dyed with a reactive monofunctional dye was retarded almost in the same manner as that dyed with Congo Red. The hydrolysis of cotton fiber dyed with dyes of higher substantivity and more bifunctional property was probably retarded to a greater extent compared to dyes of lower substantivity and less bifunctional property. © 1996 John Wiley & Sons, Inc.     

Using carbon black nanoparticles to dye the cationic‐modified cotton fabrics

Carbon black (CB) aqueous dispersion was prepared and used to dye the cationic‐modified cotton fabrics through exhaust dyeing process. The effects of CB concentration, CB nanoparticles size, dyeing bath pH, dyeing time and dyeing temperature were investigated. The color yields of dyed fabrics were evaluated on Kubelka‐Munk value K/S. The surface morphologies of cationic modified and nonmodified cotton fabrics were measured by video microscope. The fabrics presented 18.9 of the color yield with the dyeing conditions: the dyeing solution contained 2% o.w.f. CB and dyeing at 80°C for 30 min with pH 13 using a 50 : 1 liquor ratio. The images of the video microscope demonstrated a clear surface profile for the cationic‐modified cotton fabrics dyed with smaller CB particle size solutions. These results indicated that CB nanoparticles were suitable for dyeing the cotton fabrics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effects of atmospheric plasma treatment on the dyeability of cotton fabrics by acid dyes

Cotton fabrics were treated with air and argon atmospheric plasma for surface activation. Activated surfaces were grafted with two different amine compounds: ethylenediamine and triethylenetetramine. Pretreated cotton was dyed with acid dye and the effects of pretreatment on the colour strength, as well as the washing, rubbing and the light fastness of the dyeings, were investigated. Colour yield results showed that grafted ethylenediamine and triethylenetetramine enhance the dyeability of cotton fabric with acid dyes. Fourier transform infrared spectra confirmed the formed groups on the surface and scanning electron microscopy showed the etching effect of plasma.     

Process of dyeability modification and bleaching of cotton in a single bath

Graft polymerisation of the cationic monomer, methacryloylaminopropyltrimethylammonium chloride (MAPTAC), onto scoured cellulose was carried out in the bleaching process, aiming at modifying the fibre using a single bath. The extent of MAPTAC fixation on cellulose was measured. The bleaching performance of hydrogen peroxide in the presence of the modifying agent was found to be slightly reduced. The modified bleached cotton fabric was then dyed with a commercial reactive dye in the absence of salt. The dye uptake and colour strength of the modified fabric was markedly increased with an increase in the concentration of MAPTAC. This was attributed to the presence of the cationic groups of the MAPTAC which played a crucial role in attracting the anionic dyes from the dyebath. The results suggest that the dyeing properties of the modified fabric are closely dependent on the efficiency of MAPTAC fixation on cellulose during concurrent modifying and bleaching of cotton.     

Changes in dyeability and morphology of cotton fiber subjected to cellulase treatment

Unprocessed and mercerized cotton fibers were treated with commercial crude cellulase. The changes in the dyeability and structural features of the fiber due to cellulase treatment were studied. The dyeability was examined in terms of uptake of three reactive dyes and the apparent affinity of Congo Red to cotton fiber. The dyeability of the unprocessed fiber was assumed to be influenced by some impurities present in it. This fiber probably resembled polynosic fiber in molecular aggregate at a certain stage of hydrolysis. Mercerized cotton showed a similar pattern in dyeability as weight loss increased, regardless of dye species. Enzyme more easily penetrated the mercerized fiber than the unprocessed fiber. Cellulase treatment influenced the X-ray crystalline reflection pattern for the mercerized fiber but nominally influenced that for unprocessed fiber. Scanning electron micrographs revealed that cellulase treatment caused swelling of the fibrils. They also revealed that the disordered regions between the fibrils in the secondary walls were removed at low weight loss for the unprocessed fiber. The mercerized fiber at high weight loss had large cracks oblique to the fiber axis and showed no individual fibrils in the secondary wall. The primary wall was removed in the initial stage of hydrolysis for both the unprocessed and mercerized fibers. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 155–164, 1997     

Physical properties and dyeability of silk fibers modified with ethoxyethylmethacrylate polymer

The structural characteristics, physical properties, and dyeing behavior of Bombyx mori silk fibers containing ethoxyethylmethacrylate (ETMA) polymer are reported in relation to the add-on. The add-on value increased with the reaction time and attained a maximum after 60 min at 80°C. The surface of silk fibers with an add-on value of 40% showed the presence of several irregular granules, consisting of ETMA oligomers. The infrared spectrum of the silk fibers containing the ETMA polymer showed overlapped absorption bands due to the molecular conformation of untreated silk and ETMA polymer, giving evidence that the ETMA polymerization occurred inside the fiber matrix. The DSC results suggested that the thermal decomposition behavior of the silk fiber remained almost unchanged, except that the decomposition temperature shifted slightly to higher temperature. The tensile properties of the silk fiber remained unchanged regardless of the ETMA polymerization. The rate and extent of acid dye uptake was greatly increased by the polymerization of ETMA into the silk fibers as well as the transfer printing properties.     

Graft copolymerization of vinyl monomers on modified cotton. IV. Ceric-induced grafting on vinyl monomers on cellulose bearing different substituents

The influence of introducing various functional groups into the cellulose molecule on its susceptibility toward grafting with vinyl monomers such as acrylonitrile and methyl methacrylate using the Ce(IV)–cellulose redox system was studied. While cellulose bearing either cyanoethyl or carboxymethyl groups showed higher graft yields, cellulose bearing both groups showed lower yields. Presence of acrylamidomethyl groups in the cellulose molecule reduced its reactivity to grafting. The same holds true for cellulose bearing acrylamidomethyl groups along with carboxymethyl groups. On the other hand, introducing carbamoylethyl groups in the cellulose molecule enhances significantly the susceptibility of cellulose toward grafting. This is also observed with cellulose bearing cyanoethyl and carboxyethyl groups. Treating cellulose with N-methylolacrylamide in alkaline medium seems to produce a crosslinked cellulose with lower reactivity to grafting. The results obtained with the different substrates were discussed on the basis of the change in the physical and/or chemical structure of cellulose brought about during its modification as well as on the nature of the substituent groups introduced. The mode of Ce(IV) attack on cellulose was also clarified.     

Use of chitosan to improve dyeability of DP-finished cotton (II)

Chitosan was used to improve the dyeability of DP-finished cotton. Cotton fabric was treated with a mixture of chitosan, 4,5-dihydroxy-1,3-dimethyl-2-imidazolidinone (DHDMI), and catalyst in a one-step process. To investigate the effect of molecular weight of chitosan on the dyeability of treated fabrics, six chitosan samples of different molecular weights were prepared by depolymerization with sodium nitrite; 185,300, 73,200, 59,000, 21,000, 14,000, and 3,800, respectively. Chitosan improves dye uptake of direct and acid dyes considerably, and the dye uptake increases with the increase of the molecular weight of chitosan. Reactive dye uptake increases slightly in alkaline condition as the molecular weight of chitosan decreases. Higher dye uptake is obtained in acidic condition than in alkaline condition. Chitosan treatment has no discernable effect on the colorfastness to washing, but decreases the colorfastness to wet crocking by about half a point. And chitosan affects other properties of treated fabric; lower wrinkle recovery, stiffer handle, and higher breaking strength as the molecular weight of chitosan increases. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1515–1521, 1998     

New cationic agents for improving the dyeability of cellulose fibres. Part 2-pretreating cotton with polyepichlorohydrin-amine polymers for improving dyeability with reactive dyes

Pretreatment of cotton with polyepichlorohydrin-dimethylamine produces a modified cotton that can be dyed under neutral conditions with selected low-reactivity dyes using a small amount of salt or with selected high-reactivity dyes without salt. The dyeings of treated cotton exhibit improved colour yield and high wash fastness. The properties and the quality of the reactive dyeings are discussed.     

Relationship between cellulase treatment and the dyeability with a direct dye for various kinds of cellulosic fibers

The cellulosic fibers were dyed to equilibrium with Congo Red before and after cellulase treatment. The fibers examined were rayon, polynozic, cupra, flax, and cotton. It was found that the volume term for dyeing (V) was associated with weight loss (WL) caused by the cellulase treatment, for the original fibers. Apparent affinity for dyeing (AF) for the cellulase-treated fibers was calculated using a constant value of V obtained for each kind of the original fibers. The results led to the assumption that there would be two kinds of the regions that could be accessible to dye. One would be the region that was readily digested by the enzymatic hydrolysis. The other would be the region that was additionally developed by the attack of cellulase. The previously dyed fibers were hydrolyzed by cellulase. It was found that the physical bondings that formed between cellulose and Congo Red molecules would block the hydrolysis by cellulase for all the fibers examined. It was also assumed that there would be a region that could be accessible to cellulase but not entirely to Congo Red. © 1993 John Wiley & Sons, Inc.     

A new approach for dyeability of cotton fabrics by different plasma polymerisation methods

The increased dyeability of cotton fabrics in low temperature media using two different plasma polymerisation methods was investigated in this study. In the first method, fabrics were directly treated in amine plasma (ethylenediamine or triethylenetetramine). In the second method, they were first treated in argon plasma and then immersed in an aqueous amine bath. The treated fabrics were then dyed with a reactive dye (Remazol Black B) and the colour yields and fastness properties of the resulting fabrics measured. The K/S values obtained were significantly improved when compared to the untreated fabric.     

Investigation of the improved dyeability of cationised cotton via photografting with UV active cationic monomers

In this study cotton fabric was photografted with cationic monomers using UV radiation. The dyeability of cationised cotton, in the absence of salt, with three classes of dye (direct, reactive and sulphur dyes) was significantly improved due to the increased ionic attraction between the dyes and the cationic cotton. The colour fastness of the cationised fabric was similar or better than that of the untreated fabric. In addition, when cationised, crosslinked crease-resist cotton also showed improved dyeability, in the absence of salt, to direct dyes.     

Modification of cotton to improve its dyeability. Part 1 — pretreating cotton with reactive polyamide-epichlorohydrin resin

Pretreatment of cotton with the polyamide-epichlorohydrin resin Hercosett 125 produces a fibre that may be dyed with selected reactive dyes under neutral pH conditions in the absence of salt and with high fixation efficiency. The physical and mechanical properties of the modified cotton, the colour fastness of the reactive dyeings and mechanistic implications are also discussed.     

Retardation of vat dye uptake on cotton by phosphonates

Cotton dyeing with Cibanone Brilliant Yellow GMD was found to be considerably retarded by the presence of phosphonates. The extent of retardation was proportional to the number of phosphonic acid groups present in the molecule of the phosphonate.     

New cationic agents for improving the dyeability of cellulose fibres. Part 1 — pretreating cotton with polyepichlorohydrin-amine polymers for improving dyeability with direct dyes

Cotton fibres were treated with polyepichlorohydrin—dimethylamine and dyed with a selection of direct dyes. The pretreatment was found to reduce the amount of sodium chloride needed, and to increase exhaustion efficiency and perspiration fastness. The preparation and chemical characteristics of polyepichlorohydrin-dimetnylamine, the dyeing of the modified cotton and the quality of the direct dyeings are also discussed.