Dyeing properties of cotton fibres treated with liquid ammonia

Both scoured and sodium hydroxide mercerised cotton fibres have been treated with liquid ammonia atndash33.4°C using commercial operating equipment and then the ammonia removed at 130°C in a hot drum. The moisture regain and water absorbency of the fibres treated with liquid ammonia were increased compared with values on untreated fibres, whereas both these parameters on mercerised cotton fibres were decreased by subsequent liquid ammonia treatment. The fibres were dyed with CI Direct Red 2 and CI Direct Blue 1. Liquid ammonia treatment of the scoured cotton fibres increased the rate of dyeing, equilibrium dye adsorption, standard affinity, heat of dyeing and change of entropy, while the dyeing properties of mercerised cotton were adversely affected by subsequent liquid ammonia treatment.     

Influence of liquor ratio and amount of dyestuff in producing ultradeep black dyeing using mercerised and cationised cotton

Cationised cotton allows the dyeing of cotton fabrics without salt and up to 100% anionic dye utilisation. The employment of cationised cotton in the dyeing of high depths of shades with reactive dyes holds marked potential for sustainable improvements through less dye consumption, decreased water usage, and zero salt utilisation, all while obtaining shade depths darker than possible with conventional reactive dyeings. This work builds upon previous work in obtaining ultradeep dyeings of cotton utilising cationised and mercerised cotton by investigating the effects of liquor ratio in dyeing and amount of dye applied. Surprisingly, for mercerised only cotton fabric, it was found that nearly equivalent depths of shade, as indicated by L*, were obtained, irrespective of the liquor ratio and the amount of CI Reactive Black 5 applied from 7% to 10% owf. However, the strengths of the dyeings, indicated by the K/S sum, show slight increases with increasing amounts of dye, but not when the liquor ratio is lowered. Similarly, for mercerised‐cationised cotton, the liquor ratio had a negligible effect on the depth of shade obtained, but increasing the amount of CI Reactive Black 5 resulted in an increase in shade depth and colour strength. Very deep shades with high colour strength were obtained with mercerised‐cationised cotton that were not obtainable with uncationised cotton, even at a very low liquor ratio and with a drastic increase in the amount of CI Reactive Black 5.     

Alkaline treatment of cotton in different reagent mixtures with reduced water content. I. Influence of alkali type and additives

The purpose of this study was to examine the influence of some swelling agents with reduced water content on final properties of cotton fabrics. A single‐step swelling of cotton in the reagent was used. There were selected properties generally used to characterize mercerized cotton that are technologically important, such as water retention, shrinkage, stiffness, crease recovery angle, and hand. Water retention method and dyeing with CI Direct Red 81 have been used to compare the degree of swelling for different samples. Correlations have been established between structural changes induced by the swelling agents and final properties of cotton fabric. The mixtures of an alkali solution and an additive produced similar or better end‐use properties as compared with classical sodium hydroxide or ammonia treatments, combining the action of a diluted alkali solution (3.13 mol/L NaOH or KOH) and a nonalkali reagent. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2848–2855, 2006     

Development of flame retardancy properties of new halogen‐free phosphorous doped SiO2 thin films on fabrics

In this study, flame retardancy properties of fabrics treated with phosphorous (P) doped and undoped SiO₂ thin films were developed by sol–gel technique. As to this aim, P‐doped and undoped SiO₂ film were coated on cotton fabric from the solutions prepared from P, Si‐based precursors, solvent, and chelating agent at low temperature in air using sol–gel technique. To determine solution characteristics, which affect thin film structure, turbidity, pH values, and rheological properties of the prepared solutions were measured using a turbidimeter, a pH meter, and a rheometer machines before coating process. The thermal, structural, and microstructural characterization of the coating were done using differential thermal analysis/thermograviometry, fourier transform infrared spectroscopy, X‐ray diffractometry, and scanning electron microscopy. In addition, tensile strength, wash fastness, flame retandancy, and lightness properties of the coated fabrics were determined. To compensate the slight loss of tensile strength of samples, which occurred at the treated fabrics with P‐doped Si‐based solutions, the cotton fabrics were coated with polyurethane films during second step. In conclusion, the flame retardant cotton fabric with durability of washing as halogen‐free without requiring after treatment with formaldehyde was fabricated using sol–gel processing for the first time. Moreover the cotton fabrics, which were treated with P‐doped Si‐based solutions and then coated with polyurethane at second step, still has got nonflammable property. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

NaOH/urea aqueous solutions improving properties of regenerated‐cellulosic fabrics

The application of sodium hydroxide and sodium hydroxide containing urea solutions has been utilized for regenerated‐cellulosic material activation. The treatments resulted in the reorganization of cellulose fibers, hence accessibility and reactivity. In this study, sodium hydroxide–urea solutions were applied to lyocell and viscose‐knitted fabrics as finishing treatment to improve the accessibility and physical properties of textiles. Besides the mixtures, different concentrations of sole sodium hydroxide and sole urea treatment were applied. The different concentrations of urea, sodium hydroxide, and sodium hydroxide–urea mixtures were used with small increment to detect suitable concentrations and mixture ratios applied for fabrics modification. The results showed the effectiveness of applying the mixture solutions of alkali–urea particularly to CV‐knitted fabrics for improving pilling behavior, whereas for CLY fabrics, the standard alkali solutions showed the best pilling performance. The utilization of urea and sodium hydroxide–urea mixture played an important role for regenerated‐cellulosic fabrics where high alkali concentrations is not preferred to avoid fabric damages and where a mixture system could inhibit some of these aspects. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effects of sodium hydroxide and calcium hydroxide on polyester fabrics

The results of a comparison between the effects of sodium hydroxide and calcium hydroxide on poly(ethylene terephthalate) fabrics are presented. Calcium hydroxide can produce weight‐loss effects similar to an aqueous solution of sodium hydroxide. The effects of some treatment variables on weight loss, fiber diameter, bending rigidity, and strength of yarns taken from fabrics are examined. The results are explained in terms of current views of polyester alkaline hydrolysis. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 631–637, 1999     

Electron spin resonance studies of interactions of ammonia,copper, and cupriammonia with cellulose

The electron spin resonance spectra (ESR) of complexes of copper with fibrous cotton cellulose under various experimental conditions were determined. Cupric ions dissolved in solutions of strong bases, such as concentrated ammonium hydroxide, sodium hydroxide, and potassium hydroxide, formed complexes with fibrous cotton cellulose. These complexes had paramagnetic resonance properties and generated characteristic ESR spectra. Cupric ions dissolved in solutions of highly ionized neutral salts, such as sodium chloride, formed complexes with cellulose. These complexes also generated the same characteristic ESR spectra as the complexes formed in solutions of strong base. The reaction between cupric ions and cellulose was evidently very rapid and reversible. When the concentration of ammonia was decreased in, or ammonia was removed from, the cupric ion–ammonium hydroxide–cellulose complexes, the paramagnetic resonance properties of the complex were decreased or lost. Similar results were received when potassium hydroxide was removed from the complexes. The compositions of the complexes evidently are variable, that is, under different experimental conditions the relative intensities of the lines of the ESR spectra of the complexes varied, although the hyperfine splittings of the lines were constant. It was concluded that reactions of cupric ions to form complexes with adjacent hydroxyl groups on the cellulose molecule depended on an optimum spatial arrangement of the hydroxyl groups, that is, distance between the groups. Evidently, wetting of cotton cellulosic fibers with solutions of strong bases or neutral salt allowed rotation about the C₂–C₃ bond to yield this optimum arrangement. When the base or salt was removed, rotation occurred to give less favorable positions of the hydroxyl groups for complexing with cupric ions.     

A study on the exhaust dyeing of various synthetic fibres with indigo

Various synthetic fibres, namely, polyethylene terephthalate, nylon 6.6, acrylic and spandex fabrics, were dyed with indigo blue using an exhaust technique. The factors studied were sodium dithionite and sodium hydroxide concentrations, liquor/material ratio, dyeing temperatures and process times. The pH levels of the dyebaths were achieved by controlling the ratios of sodium dithionite and sodium hydroxide concentrations. Dyebath analysis at the end of dyeing showed that, in different pH regions, different forms of the indigo existed and each one exhibited different degrees of substantivity for synthetic fibres. The nonionic form exhibited substantivity for all the synthetic fibres, while the mono‐sodium phenolate form showed substantivity only in the acidic range. Synthetic fibres could best be dyed in the pH range of 5.5–6. Reflections spectra showed that indigo in synthetic fibres and when dissolved in dimethyl formamide absorbed maximally at 610 nm, while in cotton indigo absorbed at 660 nm. The fastness properties were measured and the results showed that washing and rubbing were good, while light and sublimation were moderate to poor.     

The study of rapid curing crease‐resistant processing on cotton fabrics. II. Effect of poly(ethylene glycol) on physical properties of processed fabrics

This study aimed to examine the effects of the addition of poly(ethylene glycol) (PEG) on the physical properties of processed cotton fabrics in a rapid heat‐curing crease‐resistant process. Our results show that this addition influences the moisture absorbency, crease resistance in both dry and wet conditions, and tensile strength preservation rate of the processed fabrics. Moreover, with such addition, the use of higher temperature in the process would enhance the moisture absorbency and dry–wet crease resistance but reduce the tensile strength preservation rate. The optimum condition for processing cotton fabric is to use PEG with a molecular weight of 1000 at a concentration of 10%, heated at 200°C for 30 s. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1008–1012, 2002     

One‐step dyeing of polyethylene terephthalate fabric,combining pretreatment and dyeing using alkali‐stable disperse dyes

In the conventional dyeing process, polyester and its blended fabrics are usually dyed in a weak acidic medium. In order to reduce cost and improve production efficiency, a new dyeing method – one‐step dyeing of polyethylene terephthalate fabrics, combining pretreatment and dyeing in alkali conditions – was investigated. The alkali‐stable disperse dyes Red 900, Red 902, Yellow BROB and Blue 825 were used to dye polyethylene terephthalate fabrics. The dyeing properties of polyethylene terephthalate fabrics in the case of one‐step dyeing at various pH values or sodium hydroxide concentrations were discussed in terms of colour yield, colour parameters and fastness. The performance of one‐step dyeing using alkali‐stable disperse dyes was excellent. The dyed fabric had good fastness. Wet processing could be combined and shortened. One‐step dyeing of polyethylene terephthalate fabrics could reduce the consumption of water and energy and improve production efficiency. One‐step dyeing of polyethylene terephthalate has potential application in cleaner textile production.     

Influence of chitosan posttreatment parameters on the fixation of pigment‐based inks on ink‐jet‐printed cotton fabrics

Cotton fabrics were digitally printed with pigment‐based black ink with an HP Desk‐Jet 880C printer. These ink‐jet‐printed fabrics were posttreated with chitosan samples for the fixation of the pigment‐based ink on the cotton. The influence of various parameters, including the molecular weight (MW), application method (pad–dry–cure vs pad–batch), concentration, and pH, on the degree of fixation (DF) of the pigment‐based inks was examined. The chitosan‐posttreated cotton samples were evaluated for their color strength, DF, color difference, and whiteness index values and their colorfastness properties. Chitosan samples with MWs of 150,000 and greater than 375,000 showed 100% (complete) fixation of the pigment‐based inks on the cotton fabrics. DF drastically decreased in the chitosan with an MW of less than 5000. Both the pad–dry–cure and pad–batch methods were found to be suitable for chitosan application onto ink‐jet‐printed fabrics. Chitosan with an MW of 150,000 showed 100% fixation at concentrations ranging from 0.3 to 1%. A further decrease in the concentration significantly decreased the fixation. High fixation values were achieved at acidic pH, whereas a neutral to alkaline pH resulted in poor fixation. The colorfastness properties for each parameter studied are also discussed. The posttreatment of the digitally printed cotton with chitosan was found to be very effective in fixing the pigment‐based inks. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation procedures for woven cotton and polyester/cotton fabric. Part 2 — oxidative desizing with hydrogen peroxide

Oxidative desizing with sodium hydroxide in the presence of hydrogen peroxide has been investigated as a preparatory treatment for dyeing and printing cotton and polyester/cotton woven fabric. Using statistically designed experiments, the effect of time and temperature of treatment, and peroxide and sodium hydroxide concentrations on degree of desizing, whiteness, fabric absorbency and mote removal has been determined. The major factor determining desizing rate was sodium hydroxide concentration. As peroxide concentrations increased above 0.1% o.w.f. of 35% solution desizing was retarded. Desizing was thus seen to be a hydrolytic process initiated by hydrogen peroxide. Whiteness achieved during desizing was not correlated with sodium hydroxide concentration and adequate whiteness was not achieved with the 100% cotton fabric. Whiteness of the blend was significantly influenced by all the desizing factors, while absorbency was affected by treatment time and temperature. Pure cotton was not rendered absorbent at all at below 65°C, in contrast with enzymatic desizing. Treatment for a short time in the temperature range 65–95°C gave a generally unsatisfactory level of mote removal.     

Flame resistant cotton fabrics prepared by radiation-initiated polymerization with vinyl phosphonate oligomer and N-methylolacrylamide

Radiation-initiated polymerization of vinyl phosphonate oligomer (molecular weight 500–1000) and N-methylolacrylamide from aqueous solutions was investigated with cotton printcloth, flanelette, and sateen fabrics and with cotton (50%)–polyester (50%) flannelette fabrics. Determinations were made of the effects of radiation dosage, mole ratio of vinyl phosphonate in the oligomer to N-methylolacrylamide in aqueous solution, concentration of reactants, wet pickup of solutions on fabrics, and irradiation of both dry and wet fabrics on efficiency of conversion of oligomer and monomer in solution to polymer add-on. The effects of vinyl phosphonate oligomer and N-methylolacrylamide radiation-initiated polymerization on some of the textile properties of cotton printcloth and on flame resistances of cotton and cotton–polyester fabrics were evaluated. The breaking strength of modified cotton printcloth was about the same as that of unmodified fabric; however, the tearing strength and flex abrasion resistance of modified fabric were reduced. The textile hand of the modified printcloth fabrics that had flame resistance indicated: interaction between cellulose and vinyl phosphonate oligomer–poly(N-methylolacrylamide) and uniform deposition in the fibrous cross section (transmission electron microscopy); surface areas of heavy deposits of oligomer–polymer (scanning electron microscopy); and phosphorus located throughout the fibrous cross section (energy dispersive x-ray analysis). Polymerization of vinyl phosphonate oligomer and N-methylolacrylamide was radiation initiated with cotton–polyester fabric; however, this modified fabric did not have flame-resistant properties.     

Novel application of partial carboxymethylation in the wet processing of linen fabric

Scoured linen fabrics were treated with NaOH at different concentrations (1–7N). Unscoured (gray) linen fabrics were modified via partial carboxymethylation under different conditions, including monochloroacetic acid concentration (1–4N), sodium hydroxide concentration (0.5–3.5N), reaction time (30–180 min), and reaction temperature (30–90°C). Alkali treated and partially carboxymethylated linen fabrics were bleached using H₂O₂ (20 g/L), sodium silicate (3 g/L), and nonionic wetting agent (1 g/L) at pH 10 for 150 min at 95°C. The unbleached and bleached linen fabrics (alkali treated and partially carboxymethylated) were assessed for technical properties, namely, whiteness index (W.I.), loss in fabric weight, copper number, carboxyl content, and H₂O₂ decomposition percent. A comparison was made between the properties of the two substrates. It indicates that the properties of partially carboxymethylated linen fabric were comparable, if not superior, to alkali treated linen fabric. Hence it is advantageous to introduce partial carboxymethylation in the wet processing of linen fabrics since scouring and alkali treatment can be omitted. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 996–1001, 2007     

Studies of some basic aspects in easy-care cotton finishing,IV. Effect of acid scavengers on free formaldehyde in and strength of crosslinked cotton

When cotton fabric was padded with a solution containing dimethylol dihydroxy ethylene urea (DMDHEU) (200 g/l) at pH 2.5, batched for one hour, given a wash through padding with water, dried and cured, the crosslinked cotton showed a crease recovery of 287° and 307° in the dry and wet state respectively and a retained strength of ca. 68%. Incorporation of sodium hydroxide in the washing pad accentuates the retaining strength. The latter attained a value of ca. 90% without seriously affecting the dry and wet crease recovery. However, the amount of free formaldehyde in the crosslinked cotton was quite substantial. Increasing the concentration of NaOH up to 2 g/l in the washing pad caused a significant decrease in crease recovery of and a considerable increase in the amount of free formaldehyde in the crosslinked cotton fabric. Replacement of sodium hydroxide by sodium carbonate at a concentration of up to 2 g/l reduced the amount of free formaldehyde without adversely affecting the crease recovery. Utilization of urea in the washing pad at a concentration of up to 16 g/l provided advantages in terms of lesser amount of free formaldehyde (388 ppm), higher retaining strength (ca. 80%)and excellent crease recovery (above 280°). On the other hand, addition of sodium sulphite at a concentration of up to 8 g/l in the washing pad was accompanied by a significant decrease in crease recovery, and a significant increase in the amount of free formaldehyde. Nevertheless the role of sodium sulphite as acid and formaldehyde scavanger could be ameliorated through lowering the pH of DMDHEU padding bath or addition of sodium chloride or sodium dihydrogen phosphate to this bath.     

Pigment dyeing of polyamide‐epichlorohydrin cationized cotton fabrics

A synthesized cationic reagent named polyamide‐epichlorohydrin (PAE) was used to cationize cotton fabrics which were dyed with nanoscale pigments after PAE modification. The results showed that when the PAE concentration was below 7% (owf), the K/S value increased nearly linearly with increasing of PAE concentration, and excess that concentration the K/S value did not increase further. With increasing the pH value of cationization bath, the K/S value increased first and then decreased, the maximum K/S value appeared at pH 9–10. Cotton fabrics cationized at 80°C for 20 min exhibited the best cationizing result. Both the pigment uptake and the color strength reached their own maximum values when the dye bath was neutral. When the pigment concentration was 1% (owf) the addition of 1g/L sodium chloride in the dye bath could decrease the pigment uptake while for 5% (owf) pigment concentration the uptake increased with increasing the amount of sodium chloride. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effects of a cationic diblock copolymer derived from [2-(methacryloyloxy)-ethyl]trimethylammonium chloride in the dyeing of cotton with reactive dye

A cationic diblock copolymer (PEO₄₅-MeDMA) derived from [2-(methacryloyloxy)-ethyl]trimethylammonium chloride (MeDMA) gave a positive charge to a cotton surface and provided strong attraction to an anionically charged reactive dye. PEO₄₅-MeDMA was used as the cotton pretreatment. The dyeability of cationised cotton fabrics using CI Reactive Blue 250 was found to be dependent on the PEO₄₅-MeDMA concentration. The colour strength and fastness properties of the dyed fabrics using the PEO₄₅-MeDMA copolymer and sodium sulphate were compared. The dyeability of the cotton fabrics pretreated with PEO₄₅-MeDMA indicated higher dye uptake than that of sodium sulphate. This suggests that the pretreatment of cotton by PEO₄₅-MeDMA diblock copolymer can be considered as an alternative to the use of the exhausting agent sodium sulphate.     

Wrinkle resistant properties and antibacterial efficacy of cotton fabrics treated with glyoxal system and with combination of glyoxal and chitosan system

This study examined the possibility of using glyoxal and chitosan in one‐step finishing to impart both durable press performance and antibacterial efficacy on cotton fabrics. Glyoxal treatment provided good wrinkle resistant property and fair antibacterial activity on the finished fabrics, but the loss of breaking strength retention of the finished fabrics was a main problem of this treatment. Chitosan added in the combination of glyoxal and chitosan system also provided comparable results in wrinkle resistant and antibacterial properties on the finished fabrics as the glyoxal did. The advantage of chitosan in the combination of glyoxal and chitosan system was the improvement of the breaking strength retention of the finished fabrics without affecting the durable press property of the finished fabrics. However, the yellowing of the finished fabric was still a problem when the finished fabrics were treated with the combination of glyoxal and chitosan system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1372–1377, 2006     

A coloured polyester fabric with antimicrobial properties conferred by copper nanoparticles

In this study, we aimed to produce a coloured polyester fabric through the in situ sonosynthesis of copper nanoparticles using copper sulphate, hydrazine, sodium hydroxide and polyvinylpyrrolidone. The treated fabrics were characterised by X‐ray diffraction, field emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy and elemental mapping. Moreover, mechanical properties, wettability and antibacterial/antifungal activities of the treated fabrics were evaluated. Central composite design based on the response surface methodology was used to study the effect of copper sulphate, hydrazine hydrate and sodium hydroxide on the weight gain and colour of the treated fabrics. In addition to their roles as reducing agents, hydrazine and sodium hydroxide were responsible for the simultaneous aminolysis and hydrolysis of polyester, increasing the adsorption of nanoparticles on the surface. According to the results, the reddish brown samples treated with copper nanoparticles showed excellent antibacterial and antifungal efficiencies, improved tensile strength and decreased wettability.     

Application of DMEU/SiO2 gel solution in the antiwrinkle finishing of cotton fabrics

In this experiment, cotton fabrics were treated by padding, drying, and curing with an antiwrinkle finishing reagent, dimethylolethylene urea (DMEU), in combination with different concentrations of tetraethoxysilane (TEOS) and isopropanol (IPA) at various volumes. The treated fabrics were studied to determine the effects of adding TEOS and IPA. They were also analyzed using Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) methods to examine the binding between SiO₂ and DMEU. The results showed that hydrogen bonds formed between SiO₂ and DMEU. TEOS was found to improve the antiwrinkle properties, tensile strength retention, and yellowing of the treated fabrics, although their softness was slightly reduced. The solvent IPA was shown to decrease the tensile strength of treated fabrics, although it improved their antiwrinkle properties. We observed only one stage of pyrolysis in untreated cotton fabrics, whereas the treated fabrics showed two stages. In addition, the fabrics treated with TEOS showed improved heat resistance. Our findings demonstrated that cotton fabrics showed excellent antiwrinkle properties and high tensile strength, when treated with a finishing solution composed of DMEU, 3% TEOS, IPA and water, followed by predrying and curing. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4136–4143, 2006