Ultrasonic‐assisted dyeing: II. Nylon fibre structure and comparative dyeing rate with reactive dyes

Comparative dyeing kinetics of nylon‐6 fibre with different reactive dyes using conventional and ultrasonic conditions are presented. The time/dye‐uptake isotherms are revealing the enhanced dye‐uptake in the second phase of dyeing (diffusion phase). The data of dyeing rate fit well with the integrated form of the first‐order rate equation and values of dyeing rate constant and half‐time of dyeing are discussed. Ultrasonic efficiency in accelerating the dyeing rate relative to conventional heating was examined for all dyes used to show that ultrasonics are most effective for a dyeing system which has difficulty in achieving high dye‐uptake. To clarify the role of fibre fine structure and whether it is affected during dyeing with ultrasonic waves, time‐dependent ultrasonic pre‐treatment of nylon‐6 fibres and its effect on the colour strength obtained is presented. X‐ray diffraction studies on nylon‐6 fibres conventionally and ultrasonically pre‐treated have shown that the percentage of fibre crystallinity has become higher in ultrasonically treated fibre in comparison with that of conventionally treated. Although the increased crystallinity of the fibre, which occurs simultaneously during the ultrasonic dyeing process, would retard dye uptake, it seems that the enhanced effect of power ultrasonic is high enough to overcome this side‐effect on the fibre. © 2003 Society of Chemical Industry     

A concept of reactive compatibilizer‐tracer for studying reactive polymer blending processes

A concept called reactive compatibilizer‐tracer is proposed. The latter bears reactive groups capable of reacting with its counterpart on forming a copolymer for in situ compatibilization, and fluorescent labels allowing determining very small amounts of the in situ formed compatibilizer and formation of micelles when it occurs. Owing to this concept, it is shown that a reactive compatibilizer may be very efficient at the beginning of a reactive blending process and may suddenly become completely inefficient, resulting in an abrupt and drastic increase in size of the dispersed phase domains. © 2015 American Institute of Chemical Engineers AIChE J, 62: 359–366, 2016     

Nylon 4,I: an amorphous polyamide

The melt polymerization of nylon 4, I was studied, starting with nylon-salt and nylon prepolymers (η_inh=0.25). With nylon-salt only low molecular polymers were obtained, while with prepolymers the inherent viscosity could be raised to 0.77 (3h, 270°, vac.). The cyclization of tetra methylene diamine to pyrrolidine seem to be the major disturbing factor. The polymer is glassy and could easily be melt pressed. The torsion modulus of the material at 20°C was high (1.8 10⁹ Pa) and remained high to near its T_g (138°C).     

Dye–fibre bond stabilities of some reactive dyes on cotton

Cotton fabric dyed with commercial reactive dyes of the monochloro-s-triazine, bis(monochloro-s-triazine), and bis(monofluoro-s-triazine) type was treated in buffer solutions pH 10 and 12 at 60, 85 and 98°C. Hydrolysis has been investigated using spectrophotometrical measurements of hydrolysed dye at λ_max. The percent of hydrolysed dye was calculated.     

Application of polycarboxylic acid sodium salt in the dyeing of cotton fabric with reactive dyes

In this study, the effects of polycarboxylic acid sodium salt on the dyeing of cotton with reactive dyes were evaluated by measuring and comparing the K/S values and dyeing fastnesses of the dyed cotton fabric samples. Results showed that the K/S value and dyeing fastness of cotton fabrics dyed with polycarboxylic acid sodium salt, substituting inorganic salts as exhausting agent were close to that of with sodium chloride when dip‐dyeing process was used. While, in pad‐dry dyeing, the K/S value of cotton fabric samples dyed with polyacid salts as exhausting agent was higher than that of with sodium sulfate, and the dyeing fastnesses of these samples were nearly the same. The dyeing mechanism of cotton fabric with reactive dye, using polycarboxylic acid sodium salt as exhausting agent was analyzed. The dyeing exhausting mechanism of reactive dye seems different when the inorganic salt and polycarboxylic acid sodium salt were used as exhausting agent in the dyeing of cotton fabric with reactive dye. The polycarboxylic acid sodium salt, as weak electrolyte, increased the dye‐uptake of reactive dye on cotton fabric not only by screening negative charges on cotton surface, but also by the effect of salting‐out or hydrophobic combination. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Ternary reactive blends of nylon‐6 matrix with dispersed rigid brittle polymer and elastomer

Except by elastomers, the toughness of nylon‐6 (N‐6) can be improved by the addition of rigid poly(styrene‐co‐maleic anhydride) (SMA). In this case, strength and stiffness are also enhanced. Combination of SMA with maleated ethylene‐propylene rubber or styrene‐ethene/butene‐styrene with a total content below 15% gives a ternary blend having a toughness level close to elastomer toughening, whereas the strength and stiffness reached at least the Nylon‐6 values. An explanation is a synergistic combination of both elastomer and rigid polymer toughening mechanisms. An opposite effect on mechanical behavior was found with high contents of both additives. Except for worsened strength and stiffness, in some cases, a higher elastomer content even did not enhance the toughness. This effect can be explained by too fine phase structure found, causing the matrix ligament dimension to be below its minimum critical value. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1404–1411, 1999     

尼龙6纤维酸性染料染色性能的研究现状及进展

从尼龙6纤维的酸性染料染色机理出发,讨论了影响纤维酸性染料染色性能的因素,包括热处理条件、pH值、温度等;并在此基础上,提出了改善尼龙6纤维酸性染料染色性能的方法,如加入匀染剂或其他助剂、引入特殊的结构基团、提高末端胺基含量、加入稳定剂、超声波处理和氧化还原处理等。     

Possibilities of polymer‐aided dyeing of cotton fabric with reactive dyes at neutral pH

Water‐soluble polymers have versatile application, viz., water‐soluble polyacrylates have been widely used in the reactive dyeing of cellulosic fibers and the related soaping as an important component of the leveling and washing agent. In this article, one such water‐soluble polymer, polyacrylic acid has been synthesized, characterized, and applied in conjunction with various types of reactive dyes, namely triazinyl, vinyl sulfone, high exhaustion, and bifunctional reactive dyes, along with crosslinking agents, namely glycerol 1,3‐dichlorohydrin and hexamethylene tetramine‐hydroquinone, respectively. One of the crosslinking agents (the former one) has been synthesized in the laboratory. Crosslinking agent is necessary to adhere the dye molecule onto the cellulose macromolecule. Different process sequences have been formulated and explored for dyeing purpose. All such dyeings were carried out at neutral pH. The dyed samples were assessed through color strength in terms of K/S values and their fastness properties were assessed by standard methods. All such dyeings were compared with conventional dyed samples. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis of polycondensable anthraquinone dyes and coloured nylon fibres: I

The reaction of dihydroxyanthraquinone (DHA) and amines in the presence of catalyst has been reported. We found that DHA reacted easily with hexamethylenediamine in chloroform or toluene without addition of any catalyst, and mono-or dihexamethylenediamine-substituted anthraquinone, a violet green colourant, was formed. Using the colourant as a comonomer in the polycondensation of caprolactam or nylon-6,6 salt, coloured nylon-6 and nylon-6,6 fibres were prepared.     

Melting‐reactive dyes for mass coloration of nylon based on blend compatibilization: Perylene‐3,4,9,10‐tetracarboxylic acid dianhydride

The mass coloration of nylon‐1010 with a melting‐reactive dye, an economically favorable and environmentally friendly method of coloration, is described. Perylene‐3,4,9,10‐tetracarboxylic acid dianhydride (PTAD) was used as a melting‐reactive dye for nylon‐1010, and it showed high thermal stability. A chain‐extending reaction was confirmed by an ultraviolet–visible spectroscopic analysis. The effect of the proportion of added PTAD on the intrinsic viscosity of the polymer was studied, and increased amounts resulted in increased intrinsic viscosity. The light fastness of the colored fibers was found to be 4. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2164–2167, 2002     

Non‐aqueous dyeing of cotton fibre with reactive dyes: A review

This study reviews the evolution of and recent developments in non‐aqueous reactive dyeing systems for cotton fibre. As conventional water‐based reactive dyeing causes adverse effects to the environment because of the need for huge quantities of water and chemicals, as well as generating a substantial amount of effluents, one of the alternative ways to alleviate pressure on the environment is to switch the dyeing medium from an aqueous water‐based approach to a non‐aqueous solvent‐assisted approach. Among a wide variety of non‐aqueous dyeing methods, this review focuses on several non‐aqueous dyeing systems, including dyeing textile fibres with chlorinated solvents, dyeing cotton with the use of reverse micellar systems, a dye/solvent suspension system and a non‐nucleophilic solvent‐assisted dyeing system.     

Ultrasound‐assisted emulsion polymerization of methyl methacrylate and styrene

In this article, we report on the effect of using ultrasound during emulsion polymerization. This work differs somewhat from that previously reported in that ultrasound is used in conjunction with conventional initiators. The aim is to observe the changes in the nature of polymerization and the synthesized polymer. In this work, reaction conditions and compositions typical of conventional emulsion polymerization are used. Azo‐bisisobutyronitrile and potassium per sulfate are the initiators used. The initial indication is that the rate of polymerization and the final conversion are higher when ultrasound is introduced into the polymerization system. This effect is more pronounced at lower temperatures (50°C) and low initiator concentrations (0.01%). At higher temperatures (70°C) the polymerization rate is seemingly unaffected by the use of ultrasound. The final product in all the experiments is a latex. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 101–104, 2000     

The kinetics and thermodynamics of nylon 6 fiber dyeing with hydrogen peroxide‐glyoxal redox system

Investigations were focused on the kinetics and thermodynamics of nylon 6 fiber dyeing with the hydrogen peroxide‐glyoxal redox system. We tried to understand thoroughly the difference between the new redox and the conventional dyeing system, since the mechanism of redox dyeing is a combination of free radical and ionic dyeing, whereas the conventional system is only ionic. The study consisted of measuring the dyeing transition temperature (T_D), diffusion coefficient (D_T), activation energies of diffusion, dyeing affinity, and the dyeing enthalpy and entropy. From the experimental results, the dyeing transition temperature (T_D) in the redox system is lower than that in the conventional system. But the diffusion coefficient (D_T) in the redox dyeing is larger than that in the conventional dyeing. The dyeing affinity of the free radical dyeing type (redox) is lower than that of the ionic type (conventional). Moreover, from the analysis of thermodynamics of dyeing, the enthalpy is found to be positive (endothermal reaction) in the redox system, but it is negative (exothermal reaction) in the conventional one. The entropy is also found to behave similarly, i.e. positive in the redox system, but negative in the conventional dyeing. Finally, the dyeing saturation value in the redox dyeing system is found to be higher than that in conventional dyeing. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 2105–2114, 2000     

Modification of Nylon 6 by phenol‐containing polymers

A crystalline polymer, Nylon 6, was selectively blended with various amorphous polymers containing phenolic moieties. It was found that moisture absorption by the amide group in Nylon 6 could effectively be reduced by blending with p‐Cl‐novolac at ratios as low as 2 phr (part per hundred resin). Blends of Nylon 6 with vinylphenol homopolymer and its copolymer with styrene also showed reduced moisture uptakes, but the effect was less dramatic than that of the p‐Cl‐novolac blend at all blend ratios. Novolac content in excess of 5 phr shows little additional advantage in moisture reduction. Thermal transitions of blends of Nylon 6 with poly(vinyl phenol), its copolymer, and p‐Cl‐novolac were also investigated. At a blend ratio of 5 phr, p‐Cl‐novolac caused a larger increase in glass transition temperature than the other two blends. The melting temperatures of the blends were little influenced by low levels of the amorphous polymer incorporation, but broader melting endotherms in the differential scanning calorimetry scans were observed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 295–300, 1999     

Synthesis and characterization of polyamide powders for sorption of reactive dyes from aqueous solutions

Polyamide (PA) fine powders or granules, obtained by anionic solution/suspension polymerization of lactams, were used for the sorption of reactive dye Brilliant Red HE‐3B from aqueous solutions. They provided a relatively large surface area and porosity that allowed an increased sorption rate. The visible molecular absorption spectroscopy was used to evaluate the performance of the investigated systems. Under the same conditions, the sorption capacity of polyamide particles decreases in the following manner: PA6‐powders > PA12‐powders > PA4‐granules. The effect of pH, initial dye concentration, temperature, and sorption duration on dye removal was studied for the PA6‐powder/reactive dye system. The equilibrium sorption isotherms have been analyzed by the linear, Freundlich, and Langmuir models. The data conform to a Langmuir isotherm and a pseudosecond order kinetic model, respectively. In addition, the apparent thermodynamic parameters were calculated and the obtained values support the conclusion that the reactive dye molecules are adsorbed onto PA‐powders by an entropy‐driven, endothermic process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Self‐curable aqueous polymeric dyes for printing and dyeing applications

An epoxy resin (NPES‐904, epoxy equivalent weight is 815) with a repeating unit, n > 4 was selected as a polymer backbone of polymeric dye. Water‐reducible epoxy resin was prepared by a semiesterification of its secondary hydroxy group with succinic anhydride and then dispersed to aqueous phase after it was neutralized with triethylamine. An aqueous polymeric dye was obtained from a ring opening reaction of that epoxy resin with amino group of a direct dye (soluble dye such as C. I. Acid Blue 62, C. I. Direct Orange 39 or C. I. Direct Red 2). These aqueous polymeric dye dispersions carried the average particle sizes between 50 and 90 nm. A polyaziridine was added as a latent curing agent and forming a self‐curable system of aqueous polymeric dye solution, which was stable in aqueous phase when its pH remained above 8.0. This aqueous polymeric dye was self‐cured on drying at ambient temperature and results in the formation of waterproof and solvent‐resistant polymeric dye. These self‐curable polymeric dyes had potential for jet ink printing and dyeing applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1919–1931, 2006     

Reactive dyeing of cellulosic fibers: Use of cationic surfactants and their interaction with reactive dyes

Cotton fabrics were dyed with three reactive dyes, C.I Reactive Blue 263, C.I Reactive Red 269, and C.I Reactive Yellow 208, after pretreatment of the fabrics with three alkyl trimethyl‐ammonium bromides (tmabs) having 12, 14, and 16 carbon atoms in the alkyl chain. The pretreated samples were dyed with standard dyeing methods using conventional, reduced amounts of electrolyte, and no electrolyte. Pretreatment with the three cationics (tmabs) resulted in an increase in dye exhaustion with all dyes used, whereas total dye fixation was lower for both red and blue dye and equal for the yellow, when compared to the reference untreated samples dyed according to the same standard dyeing method. The interaction between dodecyl trimethyl‐ammonium bromide and the three dyes was studied and the stoichiometry of the various dye/dodecyl trimethyl‐ammonium bromide (12‐tmab) complexes formed has been deduced. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

交联改性壳聚糖在棉织物活性染料染色中的应用

采用交联改性降解壳聚糖对棉织物进行接枝改性,考察壳聚糖接枝改性对棉织物雷马素活性染料染色性能的影响.结果表明:棉织物经壳聚糖改性后,增加了织物表面对染料阴离子的亲和力和固着力,上染率和K/S值都有所提升,其固色率也有很大提高,均达80%以上;经雷马素红RR和雷马素黄RR染色后,改性棉织物的干、湿摩擦牢度和耐皂洗褪色同未改性棉织物一样,分别为4、3~4和4级,耐皂洗沾色降低半级,为3~4级.用雷马素蓝RR染色后,改性棉织物干摩擦牢度提高半级,达4级,湿摩擦牢度和耐皂洗等级同未改性棉织物一样,分别为3~4和4级.     

Atmospheric pressure plasma‐induced decolorisation of cotton knitted fabric dyed with reactive dye

The aim of this study was to investigate the decolorisation effect of atmospheric pressure plasma treatment on knitted fabrics dyed with reactive dyes under different processing parameters, ie, air concentration, treatment duration and water content. The fabrics were dyed with reactive dye of a blue colour, and the colour depths were 0.5%, 1.5% and 3.0% on weight of fabric. The colour properties of untreated and plasma‐treated fabric samples were evaluated by means of reflectance, K/S and relative unlevelness index. The colour properties were evaluated instrumentally and quantitatively in order to study the decolorisation effect induced by atmospheric pressure plasma treatment. Experimental results revealed that the desired decolorisation effect was heavily influenced by the atmospheric pressure plasma treatment processing parameters. Although the desired decolorisation effect could be obtained by controlling the processing parameters of the atmospheric pressure plasma treatment, the treatment did not provide any significant reduction in the bursting strength of the fabric.     

Microwave‐assisted dyeing of poly(butylene terephthalate) fabrics with disperse dyes

In this study, conventional heating and microwave dielectric heating in the exhaust dyeing of poly(butylene terephtalate) fabrics with disperse dyes were studied in order to determine whether microwave heating could be used to increase the dyeability of poly(butylene terephtalate) fibre in shorter processing times and enable dyeings of adequate wet fastness to be obtained. Accordingly, the samples of 100% poly(butylene terephtalate) single jersey knitted fabric were dyed with CI Disperse Yellow 160 and CI Disperse Yellow 42, CI Disperse Red 177 and CI Disperse Red 91, CI Disperse Blue 79:1 and CI Disperse Blue 54 at 98 °C with or without microwave dielectric heating. The colouristic properties, colour fastnesses and the tensile properties of the dyed fabrics were investigated and compared with each other. Microwave dielectric heating is regarded as a tool for ‘green chemistry’ and provides many advantages over conventional heating without any deterioration in the properties of the dyed materials. Microwave heat dyeing enhances the exhaustion and the fixation of dye, and good colour fastnesses and repeatability in dyeings are achieved in short heating times of the dyebath.