Dyeing and fastness properties of phthalimide‐based alkali‐clearable azo disperse dyes on poly(ethylene terephthalate)

The properties of a series of phthalimide‐containing azo disperse dyes and azo dyes with N‐methyl phthalimide moieties in their diazo component were investigated and compared when used to colour polyethylene terephthalate. The N‐substitution of the phthalimide gave a hypsochromic effect on the colour change and better colour yields on poly(ethylene terephthalate) fabrics, probably because of the electron‐donating property of the methyl group and the higher hydrophobicity of phthalimide‐containing azo dyes compared with those containing phthalimide moieties. The results show that phthalimide‐based azo disperse dyes have excellent dyeing fastness properties and that high wash fastness can be achieved using alkali clearance. This alternative clearance method is important for reducing the environmental impact of the dyeing process by replacing reductive clearing and, in particular, by removing the need for sodium hydrosulphite, which creates a high biological oxygen demand when released in conventional disperse dyeing effluent and which generates aromatic amines.     

Effect of N,N‐diethyl‐m‐toluamide on the structure and dyeing properties of meta‐aramid and para‐aramid fibre

N,N‐Diethyl‐m‐toluamide has been widely used in the mosquito‐repellent finishing of textiles over the past few decades, but the use of N,N‐diethyl‐m‐toluamide as a dye carrier for aramid dyeing with disperse dye has been seldom reported. Meanwhile, the application of aramid fibre in clothing is limited because it is difficult to dye. In this work, the effect of N,N‐diethyl‐m‐toluamide on the dyeing properties of aramid fibre was examined by measuring the percentage disperse dye exhaustion under different conditions. In order to understand the mechanism by which N,N‐diethyl‐m‐toluamide promotes the exhaustion of disperse dye on aramid fibre, the ultraviolet‐visible spectrum of the dye and N,N‐diethyl‐m‐toluamide solution, the glass transition temperature, the crystalline structure, and the degree of orientation of aramid fibre treated with N,N‐diethyl‐m‐toluamide were measured by ultraviolet‐visible spectrophotometry, differential scanning calorimetry, X‐ray diffraction analysis, and velocity‐oriented tests respectively. The results indicated that N,N‐diethyl‐m‐toluamide not only could reduce the glass transition temperature and degree of orientation of aramid fibre but could also improve the solubility of disperse dye in aqueous solution, and therefore could enhance the percentage disperse dye uptake on aramid fibre, whereas treatment with N,N‐diethyl‐m‐toluamide showed little effect on the crystalline structure of aramid fibre. The results implied that N,N‐diethyl‐m‐toluamide was beneficial to the diffusion of disperse dye molecules into the amorphous region of aramid fibre under the dyeing conditions, but seldom affected the mechanical properties of aramid fibre.     

Exhaust dyeing of polyester‐based textiles using high‐temperature–alkaline conditions

The factors affecting the dyeability of polyester‐based textiles with disperse dyes in an alkaline medium were studied. It was found, for a given set of dyeing conditions, that (a) the appropriate conditions for attaining a higher color yield were 45 min at 130°C with pH 9 using a material‐to‐liquor ratio of 1/10; (b) increasing the Diaserver® AD‐95 concentration to 2% ows (based on weight of substrate) as well as including triethanolamine to 2% ows in the dyeing formulations bring about a significant improvement in the dye uptake; (c) both a preheat setting from 160 to 200°C/30 s and an alkaline weight reduction have a positive impact on postdyeing with the used disperse dye; (d) the extent of dye uptake as well as the color strength are governed by the type of substrate, that is, knitted fabric > spun yarn > woven fabric, nature of the dye stabilizer, that is, EDTA > Diaserver® AD‐95 > Tinoclorite® CBB > citric acid > none, as well as kind of the disperse dye; (e) direct reuse of the disperse dyebaths, without reconstitution, in the dyeing of the used substrates was shown to be feasible in a single shade and in the reverse‐order dyeings (dark → light); (f) one‐bath, one‐step exhaust dyeing of polyester/cotton‐knitted fabric using selected disperse reactive dyes combinations under high‐temperature alkaline conditions is feasible; and (g) the color and fastness properties of the resultant dyeings depend on the type of the used auxiliaries, in addition to the nature of disperse/reactive dyes combinations as well as compatibility with other ingredients. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3563–3573, 2003     

One‐bath dyeing of polyester/cotton blends with disperse and bis‐3‐carboxypyridinium‐s‐triazine reactive dyes. Part 2: Application of substantive reactive dyes to cotton at 130 °C and neutral pH†

An earlier paper reported that the reactive dyes (not the disperse dyes) were responsible for the inability to achieve heavy depths of shade, when dyeing polyester/cotton blends by a one‐bath process at 130 °C and neutral pH using reactive dyes containing a 3‐carboxypyridinium‐s‐triazinyl group. It was shown that the poor colour yield of the bis‐3‐carboxypyridinium‐s‐triazine reactive dyes was because of their low exhaustion level at 130 °C and pH of 7.0–7.5. We now report the synthesis and evaluation of some bis‐3‐carboxypyridinium‐s‐triazine reactive dye structures, possessing highly substantive chromophores, as a means of obtaining high colour yield, on 100% unmercerised cotton, under the specified dyeing conditions. The technical performance of these dyes under such conditions was compared with that of selected Novacron (Cibacron) LS and Procion H‐E dyes, applied under their recommended (atmospheric) dyeing conditions.     

Carrier‐free dyeing of radiation‐grafted polyester fabrics with disperse dyes

Carrier‐free dyeing of radiation‐grafted polyester fabrics with disperse red dye was studied in the temperature range 283–363 K. 1‐vinyl 2‐pyrrolidone (NVP), acrylic acid (AA) or their mixture was used to graft poly(ethylene terephthalate) (PET) fabric. The effects of pH of the dye solution, graft yield (GY), dyeing time (t), dye concentration (C), and dyeing temperature (T) on the colour difference (CD) of PET fabric were studied. The best dyeing condition was achieved at pH 5.5. CD increases linearly with the increase in GY, with slopes depending on the type of grafted copolymer. CD increased rapidly as the dyeing time increased; this was followed by a relatively slow dyeing rate within a few minutes. The initial dyeing rate (R) was found to increase with an increase in C and T. The dyeing rates for all grafted samples followed 0.35‐order kinetics and are temperature‐independent. Average activation energy 9.26 kJ mol^?1 is calculated for the dyeing process and is independent of the fabric treatment. Pre‐exponential rate constants 1976, 1839, and 1579 (CD/GY) s^?1 were calculated for dyeing PET samples grafted with AA/NVP mixture, NVP and AA, respectively, while 1074 CD s^?1 was evaluated for carrier dyeing of ungrafted fabric. Analysis of the kinetic parameters and the dyeing mechanism revealed that dyeing PET fabric was diffusion‐controlled. Grafting PET fabric improved significantly the dyeing affinity of the DR dye over ungrafted samples dyed in solutions containing a carrier. Copyright © 2005 Society of Chemical Industry     

Dispersant‐free dyeing of poly(lactic acid) fabric with temporarily solubilised disperse dyes from azopyridone derivatives

Poly(lactic acid) fibre is derived from annually renewable crops and known to be 100% compostable. In order to extend its environmental friendliness into the dyeing process, dispersant‐free dyeing of poly(lactic acid) fabric with three temporarily solubilised azo disperse dyes based on hydroxypyridone moiety containing a β‐sulphatoethylsulphonyl group was investigated. The dyes were successfully applied to poly(lactic acid) fabric without the use of dispersants. The colour yields of the dyes on poly(lactic acid) fabric were observed to be dependent on dyebath pH and dyeing temperature. The optimum results were obtained at pH 4–5 and 110 °C. One of the dyes showed a colour yield as good as that of a commercial disperse dye and good build‐up on poly(lactic acid) fabric. All of the dyes could be alkali cleared owing to ionisation of the dye under mild alkaline conditions. Wash fastness was good to very good, and light fastness was good. The chemical oxygen demand levels of the poly(lactic acid) dyeing effluent from the dyes were considerably lower than those from a commercial disperse dye.     

Solubilisation kinetics of some monoazo naphthalimide disperse dyes containing butyric acid and investigation of fastness properties of the dyes on polyester

In this paper, the solubilisation kinetics of three novel monoazo disperse dyes based on naphthalimdes incorporating a butyric acid group were investigated in different conditions using spectrophotometry. All dyes showed a reasonable level of solubilisation in alkaline media. Kinetic studies of the solubilisation reaction of the dyes in alkaline media showed that the rate of solubilisation of all dyes is a pseudo first‐order reaction equation. The rate constants of the solubilisation reaction of the dyes in alkaline media indicated that dye 3 , which is prepared by the diazotisation of 4‐amino‐n‐butyric acid 1,8‐naphthalimide and coupled with N,N‐diethy‐n‐hydroxyethyllaniline, has the highest rate of reaction and dye 1 , which is prepared by the diazotisation of 4‐amino‐n‐butyric acid 1,8‐naphthalimide and coupled with N,N‐diethylaniline, has the lowest rate. The dyes were applied on polyester fabrics and their fastness properties were examined. The dyed fabrics showed a good to excellent degree of wash and rubbing fastnesses after replacing reduction clearing with alkali clearing.     

Effect of microencapsulation on dyeing behaviors of disperse dyes without auxiliary solubilization

Microencapsulated disperse dye can be used to dye hydrophobic fabric in the absence of auxiliaries and without reduction clearing. However, little available information for dyeing practice is provided with respect to the effect of microencapsulation on the dyeing behaviors of disperse dyes. In this research, disperse dyes were microencapsulated under different conditions. The dyeing behaviors and dyeing kinetic parameters of microencapsulated disperse dye on PET fiber, e.g., dyeing curves, build up properties, equilibrium adsorption capacity C_∞, dyeing rate constant K, half dyeing time t_1/2, and diffusion coefficient D were investigated without auxiliary solubilization and compared with those of commercial disperse dyes with auxiliary solubilization. The results show that the dyeing behaviors of disperse dye are influenced greatly by microencapsulation. The diffusion of disperse dyes from microcapsule onto fibers can be adjusted by the reactivity of shell materials and mass ratios of core to shell. The disparity of diffusibility between two disperse dyes can be reduced by microencapsulation. In addition, the microencapsulation improves the utilization of disperse dyes due to no auxiliary solubilization. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Novel azo dyes derived from phthalimide. Part 2: Dyeing properties and colour fastness on polyester fibres†

The coloration and fastness properties of 18 carbocyclic monoazo disperse dyes bearing a phthalimide ring fused to the aromatic ring of their diazo components have been investigated. In each case, the phthalimidyl nitrogen atom was substituted with either a butyl, sec‐butyl or isopropyl group, while the adjoined phenyl ring bore a substitution pattern typical of commercial colorants. Dye uptake and build‐up onto both conventional and microfibre polyester through exhaustion dyeing were examined: while the expected tendency of greater exhaustion on microfibre was noted, there were few clear trends with respect to dye structure. The nature of the N‐alkyl group made no consistent difference to dye uptake. Attempts to explain the observed percentage exhaustion values by mapping them to calculated partition coefficient or solubility parameter values were unsuccessful. Wash fastness tended to be best for blue dicyano‐substituted derivatives, which may be as a result in part of these substituents promoting hydrolysis of the adjacent phthalimide ring to give more soluble phthalate species. In contrast, the dicyano dyes had relatively poor photostability compared with their unsubstituted analogues.     

Blue core–shell nanospheres prepared by dyeing poly(styrene‐co‐methacrylic acid) dispersions

Blue poly(styrene‐co‐methacrylic acid) nanospheres were prepared by dyeing polymer dispersions with CI Disperse Blue 56. The coloured nanospheres had a clear shell with a thickness of 32.5 nm. The average diameter of the nanospheres increased from 288 to 353 nm, and the glass transition temperature was raised from 109.6 to 117.9 °C after coloration. Ultraviolet‐visible absorption spectra, transmission electron microscopy, and differential scanning calorimetry show that the amino and/or hydroxyl groups of the disperse dyes formed hydrogen bonds with the carboxyl groups on the surfaces of the nanospheres during the coloration process, resulting in increased particle sizes and shell layers. The dye content increased almost linearly with increasing dye concentrations or dyeing temperatures within a certain range. By increasing the pH of the dyeing bath from 4 to 5, the dye content increased sharply from 0.68 to 1.49% because of the ionisation of the carboxyl groups of the macromolecules.     

Coloration properties and clearability of phthalimide‐derived monoazo disperse dyes containing ester groups

The coloration properties and clearability of disperse dyes prepared from phthalimide‐derived diazo components and a coupling component containing two carboxylic acid ester groups have been investigated. Members of the series featured C₂–C₄ alkyl substituents on their phthalimidyl nitrogen atom. The nature of the N‐alkyl group made no consistent difference to dye uptake on polyester. No correlation was found between percentage exhaustion and calculated solubility parameters. Wash fastness was extremely good. Comparison with analogues indicated that the diester motif was of significant extra benefit to wash fastness for phthalimide‐derived dyes, but did not increase photostability above the lower range of commercial acceptability. Clearability was compared with that of dyes lacking one or both hydrolysable structural features, as well as with that of some industrial dyes. The novel dyes exhibited a greater tendency to be solubilised, consistent with hydrolysis of their ester and/or phthalimide functionalities.     

Poly(ethylene terephtalate) films modified with N,N‐dimethylacrylamide: Incorporation of disperse dye

Poly(ethylene terephtalate), PET, can be modified with N,N‐dimethylacrylamide to obtain a better incorporation of disperse dye (Disperse Blue 79). Minimal variations in the decomposition at 10% level, melting, and glass transition temperatures, show that the thermal stability of modified PET films does not change when compared to nonmodified PET. The atomic force images show nanopeaks formation on the surface due to the modification. Modified PET films show a decrease in the contact angle and then, an increase in the superficial tension measurements, when compared to the value of 37 ± 1 dynes · cm⁻¹(nonmodified), with values liying in the range of 42–46 ± 0.5 dynes · cm⁻¹. The data obtained by photoacoustic spectroscopy (PAS) for dyed PET films show a dye peak at 580 nm. The data analysis of the peak area show that PET films modified with N,N‐dimethylacrylamide for 15 min at 85°C, dyed for 6 h at 85°C with a dye concentration of 0.333 g/L, incorporate three times more dye than the nonmodified films dyed in the same conditions. By the data obtained from PAS, it was possible to calculate the depth profile of dyeing with values around 54 μm. Factorial analyses show that the dyeing time was the most important variable. The major amount of incorporated dye was obtained by the following combination of variables: temperature and time of modifier treatment were, respectively, 72.5°C and 15 min; time and temperature of dyeing were, respectively, 90°C and 195 min for a dye concentration of 0.133 g/L. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 269–282, 2000     

Improving the UV resistance of aromatic poly(l,3,4‐oxadiazole) fiber using a disperse dye modified with octavinyl POSS. Part 1: Preparation of dye and dyeing

Modified dyes were obtained by grafting of disperse dyes with octavinyl polyhedral oligomeric silsesquioxanes (POSS) using a Friedel‐Crafts alkylation reaction and using different ratios of POSS and the original disperse dye. The modified dyes are used to dye aromatic poly(l,3,4‐oxadiazole) (p‐POD) fiber to improve its UV resistance. Then the structure of the modified dye is characterized by Fourier transform infrared spectroscopy and NMR, and the effects of the structure of the modified dye and the dyeing conditions on the UV resistance and color strength (K/S value) of the dyed samples are investigated. The results indicated that the UV adsorption peaks of the modified dye solutions are located at the specified UV wavelengths. The UV resistance of the p‐POD fiber dyed with the modified dye (1:3) can be effectively improved, and the dyed p‐POD fiber can obtain a higher K/S value simultaneously. During the dyeing process, increasing the dyeing temperature and prolonging the dyeing time are both beneficial in improving the anti‐UV ability of the dyed p‐POD fiber; these changes can effectively promote the fixation of dye molecules into p‐POD fibers due to stimulating the motion of dye molecules and p‐POD macromolecules. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44745.     

Ozone applications for after‐clearing of disperse‐dyed poly(lactic acid) fibres

In this study, the effectiveness of the ozonation process, in neutral distilled water at room temperature, as a clearing process for disperse‐dyed poly(lactic acid) fibre fabrics is investigated. The efficiency of simultaneous decolorisation of dyebath effluent and clearing of dyed poly(lactic acid) in the cooled dyebath after completion of the poly(lactic acid) dyeing cycle is also explored. Conventional alkaline reduction clearing with sodium dithionite was chosen as a control clearing process for comparison. Wash fastness, colour difference, colour removal (in Hazen) and chemical oxygen demand values were determined and compared. Long ozone treatment times at high ozone dose resulted in unacceptable colour differences. The colour difference problem was solved by use of lower ozone dose; however, a warm soaping step had to be added to the after‐clearing sequence in order to achieve the desired fastness properties. A 33% reduction on the chemical oxygen demand load of the total process (dyeing + after‐clearing) could be achieved by ozone after‐clearing instead of using a conventional reduction clearing treatment. The addition of the warm soaping step to improve the fastness properties of the ozonated samples increased the total chemical oxygen demand of the process (dyeing + ozonation in water + warm soaping), but a 12–18% reduction on the chemical oxygen demand load of the total process was observed when compared with the conventional treatment sequence (dyeing + reduction clearing).     

Synthesis of temporarily solubilised azo disperse dyes containing a β‐sulphatoethylsulphonyl group and dispersant‐free dyeing of polyethylene terephthalate fabric

Disperse dyes containing a β‐sulphatoethylsulphonyl group have temporary solubility and can be applied for dispersant‐free dyeing of hydrophobic fibre. Six novel temporarily solubilised azo disperse dyes having a β‐sulphatoethylsulphonyl group in their structures were synthesised, and their dyeing properties on polyester were investigated. As a dye intermediate, a diazo component having dibromo groups was prepared, and 4‐diethylamino‐4′‐(2‐sulphatoethylsulphonyl‐4,6‐dibromo)azobenzene dyes were prepared by a diazo‐coupling reaction. Then, the dyes containing dicyano groups were prepared by cyanation of corresponding dyes with dibromo groups. The absorption maxima of the dyes were affected by the substituents in the diazo and coupling component rings and varied from 434 to 616 nm in dimethylformamide. Polyethylene terephthalate woven fabric could be dyed with the synthesised temporarily solubilised dyes without using any dispersants. Dyebath pH affected the K/S value at maximum absorption as well as percentage exhaustion on polyethylene terephthalate fabric, and the optimum pH was 5. The dyes gave brownish orange, red, purple, and greenish blue hues on polyethylene terephthalate fabrics, and colour build‐up was good. Wash fastness was good to excellent, rubbing fastness was moderate to excellent, and light fastness was poor to moderate.     

Silicon‐containing anionic water‐borne polyurethane with covalently bonded reactive dye

A silicon‐containing water‐borne polyurethane (PU) polymer with hydroxyl side groups was synthesized that was stable in basic conditions and also capable of reacting with a reactive dye to form a covalently bonded dye molecule. The silicon‐containing anionic water‐borne PU prepolymer was synthesized from H₁₂‐4,4′‐diphenylmethane diisocyanate (H₁₂‐MDI), polytetramethylene glycol, polydimethylsiloxane (PDMS), 2,2′‐bis(hydroxymethyl), propionic acid (anionic centers), and triethyleneamine using the prepolymer mixing method. Water was then added to emulsify and disperse the resin to form an anionic water‐borne PU prepolymer. N‐(2‐Hydroxyethyl ethylene diamine) (HEDA) was used to extend the prepolymer to form a water‐borne PU polymer with a side chain of hydroxyl groups, which can further react with the reactive dye to form a dyed PU. The reactive dye of chlorosulfuric acid esters of sulfatoethyl sulfones can react with the water‐borne PU polymer. Behaviors of alkali resistance and dyeing properties were observed. In consideration of thermal properties, the dye‐grafted PU polymers exhibited lower glass‐transition temperatures for soft segments and hard segments than those without dye. Concerning mechanical properties, it was found that the modulus and the strength of the dyed PU polymers decreased with grafting of the dye molecule, but elongation at break was increased. The alkali resistance increased with PDMS content. For dye‐uptake properties, the percentage of dye grafting was over 90%. Also, the dye‐grafted PU exhibited a lower percentage of dye migration than that of polymers with ethylene diamine instead of HEDA as a chain extender, and showed greater colorfastness to light. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2045–2052, 2003     

Dyeing mechanism and model of nylon 6 fiber dyeing in low‐temperature hydrogen peroxide–glyoxal redox system

This article reports the results of a study of nylon 6 fiber dyed in a low‐temperature hydrogen peroxide–glyoxal redox system. It was expected that the dyed fiber would have better dye fastness and higher economic value than would conventional fiber. In addition, this article presents the proposed mechanism for and model of a free‐radical dyeing system as well as a derived theoretical equation. From the experimental results, it was found that formation of covalent bonds by the coupling of the dye and the fiber radical in free‐radical dyeing was only 25%–40%, whereas with the conventional type of ionic dyeing, it was almost 60%–75%. Because the initiation efficiency of free‐radical formation is affected by many factors, such as the pH of the dye bath and the concentrations of the oxidant and reductant, the aims of this study were to investigate the formation of free radicals and the effects on dye uptake of the concentrations of dye, oxidant, and reductant and of the fiber amine end group. In addition, the dyeing properties of dyed fiber were investigated, and the dyeing order and rate constant of the rate equation were evaluated from the experimental data. From the experimental results, the following conclusions were drawn. (1) The hydrogen peroxide–glyoxal redox system produced many free radicals in the dye bath as temperature reached 70°C. (2) The amine end group in the nylon fiber was the main site of ionic and covalent bonding between nylon 6 fiber and dye. (3) The proposed model of free‐radical dyeing showed, from the fit of the experimental data into the equation and the evaluation of the equation parameters, that the order fit the theoretical value well, with the rate constant dependent on the dyeing conditions; at pH = 3, it could match the equation's best (rate equation of the proposed model: d[D]_R/dt = k_A[GO]¹[H₂O]^m[D]^1/2[F]^1/2). (4) The optimum dyeing conditions in the hydrogen peroxide–glyoxal redox system were: [H₂O₂] = 0.15–0.20M, [glyoxal] = 0.07–0.10M, pH = 3, dyeing temperature = 70°C, and dyeing time = 45–50 min. (5) The redox dyeing system had better dye fastness than did the conventional system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4197–4207, 2006     

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.     

Effects of a pretreatment with N‐methylmorpholine‐N‐oxide on the structures and properties of ramie

To improve the dyeing properties of ramie, the ecofriendly organic solvent N‐methylmorpholine‐N‐oxide (NMMO) was used to substitute sodium hydroxide as a ramie‐fiber swelling solvent. Through padding and baking pretreatment, ramie fabric was modified by an NMMO aqueous solution. Ultraviolet–visible spectrophotometry, Fourier transform infrared spectroscopy, X‐ray diffraction, and differential scanning calorimetry were used to investigate the effects of NMMO pretreatment on the structure of the ramie, whereas the color strength (K/S, where K is the light absorption coefficient and S is the scattering coefficient), adsorption isotherm, and dye uptake rate curve were measured to investigate the effects of NMMO pretreatment on the dyeing properties of the ramie. The results show that the ramie fiber experienced a limited and irreversible swelling because of the partial breakage of interhydrogen and intrahydrogen bonds of cellulose molecules in the amorphous area, but the crystal and chemical structure of the ramie fiber did not change obviously under the experimental conditions. The K/S value of the NMMO‐modified ramie fabrics dyed with reactive dyes increased by about 100%, and the dye uptake increased by 27.88% compared to that of the raw sample, whereas the standard affinity and diffusion coefficient value of the reactive dyes on the NMMO‐modified ramie fabric were higher than those of the raw ramie fabric. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Acid‐dye‐dyeable polyacrylonitrile/ poly(N,N‐dilkylaminoethylacrylate) acrylic blend fiber

An acid‐dye‐dyeable polyacrylonitrile/poly (N,N‐dilkylaminoethylacrylate) blend fiber was prepared. On the basis of research for the dye uptake, color strength, tensile strength, and breaking elongation of the polyacrylonitrile/poly (N,N‐dilkylaminoethylacrylate) blend fiber, it was found that the blend fiber and its fabrics for acid dyes possessed favorable dyeability and mechanical properties. The effect of the polyacrylonitrile ratio on the blend fiber was examined. The optimum dyeing‐process parameters were determined. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007