Ink‐jet printing process for lyocell and cotton fibres. Part 2: The relationship of colour strength and dye fixation to ink penetration

The colour appearance on ink‐jet printed textiles is influenced by a range of factors, including the chemical and physical nature of the fibre, dye–fibre affinity, pretreatment and fabric structure. Regression analyses were conducted to study the correlation between colour strength, fixation and ink penetration obtained by ink‐jet printing lyocell fibres (standard Tencel and Tencel A100) and cotton with an ink based on a monofunctional reactive red dye. The fixation was highest on Tencel A100, followed by standard Tencel and then cotton, while colour strength was highest on standard Tencel followed by cotton and Tencel A100. A linear relationship between colour strength and ink penetration was found with cotton, indicating greater dependence of depth of shade on ink penetration than on standard Tencel and Tencel A100 fabrics, where the interrelationships were more complex, but of low statistical significance. A schematic representation is proposed illustrating the mechanism of ink penetration into pretreated fibres, which provides a reasonable interpretation of the events occurring as dye penetrates into and fixes onto the fibres.     

Assessment of uniformity of fibre coloration in Tencel woven fabrics dyed using reactive dyes

Weave structure and fabric density has an influence on dye penetration. The uniformity of dyeing, expressed as the uniformity of fibre coloration, of Tencel woven fabrics comprised of different weave structures, was assessed. The fabrics were dyed by exhaust and continuous dyeing methods using selected reactive dyes. Cross‐sectional images were captured and then given a rating 1–5 with respect to the depth of the fibre filaments of the yarn of the woven fabric. The images were assessed both subjectively and objectively. The uniformity of fibre coloration was expressed in terms of the standard deviation, mean value and histogram analysis such as dispersion and bandwidth. Objective assessment of uniformity of fibre coloration is a more accurate and quicker method than visual assessment and can be used to assess the uniformity of fibre coloration of woven and knitted fabrics dyed by any class of dyes. Improvement of the uniformity of fibre coloration of Tencel fabrics of various weave structures by causticisation of the fabrics and by modification to the padding process was investigated.     

洗涤剂用酶的复合效应研究

以国产碱性蛋白酶、脂肪酶和纤维素酶为对象，研究了3种酶共存时蛋白酶对脂肪酶和纤维素酶活力的影响。结果表明，在实际洗涤液浓度下蛋白酶对脂肪酶和纤维素酶的活力并无明显负面影响。研究了3种酶在各种复合状态下的去污性能及其协同作用，结果显示上述3种酶的任何2种酶复合时均具有一定的协同效应，尤其是蛋白酶与脂肪酶或纤维素酶复合能获得显的协同效应。蛋白酶与脂肪酶或纤维素酶复配能使去污力相对提高50％以上。采用响应面分析法对蛋白酶／脂肪酶／纤维素酶三元复合酶的协同效应进行了优化，获得了其回归方程和最优组成。     

新型化学纤维与染料的关系

介绍了涤纶超细纤维、Ｔｅｎｃｅｌ纤维及氨纶、锦纶等新型纤维的特点及其发展现状。通过对染色机理的分析,论述了适用于上述纤维的各类印染染料之特征。     

Tensile and elastic behavior of tencel continuous filaments

Tencel is a regenerated cellulose fiber produced using an environmentally‐responsible dry‐jet wet‐spinning process, which contributes to its excellent mechanical properties. In this study, the tensile properties of Tencel continuous filaments are characterized and the effect of twist on mechanical properties, including breaking load and extension, are considered. Peak strength was obtained in Tencel filaments of 140 t m^?1. The elastic behavior of Tencel monofilament was observed by assessing the recovery from strain‐induced energy and the elastic recovery was found to be low. Along with time dependency, Tencel has the ability to stabilize its deformed state by forming new crosslinks, and this influences the elastic behavior. In simple extension cycles, the same low elasticity was observed. Cumulative extension cycles were also performed to characterize the behavior of filaments subjected to repeated strain and to determine the resultant hysteresis effects. Permanent elongation was observed at 2% imposed strain, which suggests that the filament has low extensibility. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1496–1503, 2006     

Coloration of Apocynum venetum/cotton blends with an acid dye through combined pretreatment using cationic nanoparticles

Cationic copolymer nanoparticles were used to modify Apocynum venetum/cotton blended fabrics. The modified blends were then dyed using CI Acid Red 14. In order to enhance the colour performance, the effects of combined pretreatment using nanoparticles and sodium hydroxide (NaOH) or carboxymethylcellulose (CMC) or plasma were investigated. The results show that combined pretreatment with NaOH and nanoparticles improved the dyeing effect. The optimum concentrations of NaOH and nanoparticles were 100 and 2 g l⁻¹ respectively. In addition, using CMC to pretreat the fabrics could also improve the acid dyeing performance. However, the combination of plasma pretreatment and cationic nanoparticle modification produced the best colour performance for acid-dyed A. venetum/cotton blends. The dye exhaustion rate is highest (up to 95%) with plasma pretreatment. Scanning electron microscopy revealed that combined treatment with plasma and nanoparticles resulted in a far greater number of nanoparticles being deposited on the fibre surface. X-ray photoelectron spectroscopy indicated that the pretreatments with different procedures significantly changed the chemical components of the fibre surfaces. The aromatic rings of acid dye molecules covered the fibre surfaces after plasma and nanoparticle pretreatment and acid dyeing.     

Studies on Some New Reactive Disperse Dyes

The preparation of some new reactive disperse dyes which can be used for dyeing 100% synthetic and fibre blends is described. The preparation of some disperse dyes containing a chlorohydrin group is also described. This radical is the precursor of the epoxide reactive group in the active form of these dyes. Dyeings produced on various fibre blends by a two–stage high–temperature and by a carrier–dyeing technique are assessed. It was found that dyeings produced by the high–temperature technique were brighter, more level and possessed much better technical properties than those obtained using the carrier–dyeing method. The fastness properties of dyed samples were determined and found to be comparable with those of conventional disperse and reactive dyes. The colour yield was also determined in order to examine the possibility of obtaining deep dyeings on blended fibres, and to evaluate the potential commercial use of these dyes for dyeing blends as well as 100% synthetic–polymer fibres.     

Graft copolymer modification of polyethylene–polystyrene blends. II. Properties of modified blends

The use of graft copolymers of styrene onto polyethylene as additives to improve the mechanical properties of polyethylene–polystyrene blends is described. Blends containing equal proportions of low-density polyethylene and polystyrene were selected for this study since this composition represents the poorest balance of properties in this system. Graft addition generally increased both the yield strength and the elongation at break of the blend. Of the grafts employed, those prepared at an irradiation dose near 0.5 megarad appear optimal for this purpose. These conditions apparently balance the beneficial effects of grafting extent and the detrimental effects of crosslinking, both of which increase with irradiation dose.     

Synthetic fibres in the dyehouse — the manufacturers' role

This paper briefly outlines two recent examples of how Courtaulds' research programmes have led to fibre innovations designed to assist the dyer in his trade. Tencel is the world's first commercially available solvent-spun cellulose fibre, possessing extremely good dyeing characteristics. The yield of reactive dyes is exceptional, particularly in printing, where causticisation or mercerisation is no longer necessary to improve dye yields as with conventional viscose or cotton. Xtol is a new diacetate fibre. Its ability to be processed at higher temperatures than conventional diacetate without delustring brings improved fastness and higher dye yields.     

Dyeing of Blends of Wool and Man-made Fibres

The blending of wool with man-made fibres is described generally. It is shown how the results of dyeing wool-man-made-fibre blends are controlled by physical properties such as wet tensile modulus; it is also indicated how a wide range of coloured effects can be obtained with different man-made fibres. The dyeing of blends containing wool is considered first from the point of view of the circulation of dye liquor through a mass of fibre and then of the relative dye absorption by the blend components. The relationship between tensile modulus and behaviour in wet processing is illustrated by laboratory work on the measurement of rate of flow through a mass of loose fibre. It is concluded that the dyeing of loose fibres in blend form could be a practical proposition and in some cases could result in over-all economies in processing. The relative dye absorption by fibres in blends is discussed in detail and fibres are classified according to their substantivity for acid or for direct dyes. One group consists of regenerated-protein, polyamide, and elastomeric fibres, a second group of viscose rayon fibres, and a third, larger, group of hydrophobic fibres, e.g. acetate, polyester, and acrylic fibres. The cross-staining of wool by dyes intended for the man-made fibre is considered, with particular reference to blends of acetate and wool; the effect of dyebath conditions, e.g. pH and temperature, is referred to and methods are outlined for minimising staining. Some three-fibre blends are then briefly considered. Finally, possible future developments, with particular reference to blends, are discussed.     

混合酶用于激光打印废纸脱墨的研究

将生物脱墨技术应用于惠普激光打印废纸脱墨工艺中,在尽量减少碱的用量或完全不用碱的情况下,达到了脱墨的效果和环保的目的。比较了纤维素酶、淀粉酶和脂肪酶以及它们的混合酶对脱墨的影响。分别研究了酶种类和混合酶的配比、温度、pH值对脱墨效果的影响。实验结果表明:纤维素酶和淀粉酶的混合使用有较好的脱墨效果,能使脱墨浆白度达到76.93%(ISO),接近白纸的白度80.48%(ISO)。其最佳工艺条件为:反应温度40℃、pH=9—10、纤维素酶与淀粉酶质量比=1∶1.5。为脱墨工艺的研究提供了理论依据。     

Polypropylene/cycloolefin copolymer blends: effects of fibrous phase structure on tensile mechanical properties

Tensile mechanical properties of polypropylene (PP)/cycloolefin copolymer (COC) blends were studied using an Instron tensile tester. As COC was expected to impart enhanced mechanical properties to the blends, their modulus, yield strength, tensile strength and tensile energy to break were measured as functions of blend composition. With regard to the reported sensitivity of the COC structure to thermal history, the influence of annealing at two different temperatures was also tested. The attention was primarily concentrated on blends with the volume fraction of COC in the interval 0<v₂<0.40, where COC formed (short) fibres almost uniaxially oriented in the direction of injection moulding. In the interval 0.40<v₂<0.75, the blends consisted of partially co-continuous components. Two different models were applied in the analysis of mechanical properties, namely (i) the rule of mixtures for fibre composites and (ii) the equivalent box model for isotropic blends (employing the data on the phase continuity of components obtained from modified equations of the percolation theory). Experimental data on the studied mechanical properties were better fitted by the models for fibre composites. Annealing of the samples (75 °C for 45 days; 120 °C for 3 h) did not markedly affect the tensile modulus, yield stress, and stress at break of the blends. On the other hand, the strain at break was markedly reduced by the annealing up to v₂=0.2; COC and the blend with 75% of COC ruptured in a brittle manner without yielding.     

Modification of polypropylene fibres with cationic polypropylene dispersion for improved dyeability

Polypropylene (PP) fibres are important hydrophobic fibres which are used in the production of functional textiles such as sports textiles. The absence of functional groups and low polarity make PP fibres difficult to dye, thus mass coloration during fibre extrusion is the major technique applied today. However, the disadvantage of mass coloration is the low flexibility and the demand to produce high volumes. A new method to modify the surface of PP fibres utilises the deposition and thermal fixation of cationic PP dispersion. Through padding and thermal fixation of a cationic PP dispersion, dyeable 100% PP fibres can be obtained. The effects of fixation temperature, and of the amount of dispersion used on the modified fibres were studied using Fourier Transform‐infrared spectroscopy, laser scanning microscopy, dyeing experiments with CI Acid Red 151, and by determining selected fastness properties. The results indicate the potential of this new method to produce surface‐modified 100% PP fibres, which can be dyed in conventional acid‐dyeing processes and therefore used in fibre blends, for example in combination with wool.     

Application of a microassay method to study enzymatic hydrolysis of pretreated wheat straw

BACKGROUND: The conversion of lignocellulosic biomass to ethanol includes a disruptive pretreatment process followed by enzyme‐catalyzed hydrolysis of the cellulose and hemicellulose components to fermentable sugars. As the cost and hydrolytic efficiency of enzymes are major factors that restrict the commercialization of biomass conversion processes, significant efforts are made nowadays to improve the enzymatic mixtures and make the process cost‐effective. RESULTS: In this work, enzymatic microassays have been developed and validated to test new different enzymatic formulations on real lignocellulosic substrates. Homogeneous handsheets from steam pretreated wheat straw were elaborated to be used as substrate. The microassay was adapted to test both water‐insoluble solids and the whole slurry as substrates. Results in hydrolysis microassays were comparable with those obtained in standard flask assays using pretreated wheat straw. Moreover, using the enzymatic microassays, two novel preparations have been evaluated, demonstrating the ability of microassays to discriminate between different enzymatic mixtures. CONCLUSIONS: This enzymatic microassay represents a rapid method to test the performance of new selected cellulase enzymes on real pretreated lignocellulosic substrates. This microassay will enable evaluation of enzyme components separately, or optimized mixtures. Copyright © 2010 Society of Chemical Industry     

Preparation and properties of thermoplastic polyurethane/ultra high molecular weight polyethylene blends

The blends of thermoplastic polyurethane and ultra high molecular weight polyethylene (UHMWPE) were prepared by a co‐twin screw extruder. Phase separation morphology of the blends was confirmed by the SEM observations. The incorporation of UHMWPE is detrimental to the mechanical properties of the blends prepared from stiffer TPU, whereas is beneficial to that of TPU with low hardness. The tribological behaviors of neat TPU and its blends were studied by the means of a block‐on‐ring apparatus. It was found that UHMWPE could greatly improve the tribological properties of TPU matrix both under dry sliding and water lubricating conditions due to the excellent self‐lubricating property of the UHMWPE materials and furthermore improve the wear failure limit of TPU. POLYM. COMPOS., 36:897–906, 2015. © 2014 Society of Plastics Engineers     

多相聚合物共混体系增容剂的研究与发展

本文综述了多相聚合物混体系增容剂的研究与发展，介绍了各类增容剂的特点及应用，依据其加入共混体系的方法和与其共混组分间的作用进行了分类。     

青霉纤维素酶酶解芦竹的研究

以青霉纤维素酶酶解芦竹,探讨了酶解温度、酶解时间、pH值和酶载量对芦竹酶解效果的影响。结果表明,青霉纤维素酶酶解芦竹的最适条件为:酶解时间72h、酶解温度45℃、pH值4.8、酶载量30FPU.g-1 DM,在此条件下,葡萄糖产率为(61.75±1.22)%、木糖产率为(40.07±6.88)%;通过添加商业酶调配酶系中不同酶活比例,可进一步提高还原糖产率,当增加β-葡萄糖苷酶至40CBU.g-1 DM时,葡萄糖产率达68.96%、木糖产率达98.16%。     

Improvement of cotton cloth soil removal by inclusion of alkaline cellulase from Bacillus sp. KSM-635 in detergents

Alkaline cellulase from Bacillus sp. KSM-635 (EC 3.2.1.4) had reproducible detergent effects on cotton cloth that was artificially or naturally soiled with oily and/or particulate matter, under European washing conditions. The detergent effects of the cellulase, in combination with surfactants, apparently were the result of enzymatic action on amorphous regions of cotton fibers in which soil was trapped. The contribution of cellulase to soil removal increased as (i) the amount of soil in the amorphous regions of fibers in test fabrics was increased and (ii) the inhibition, by soil that adhered to the fibers' surfaces, of the action of the cellulase on fibers was reduced. Alkaline cellulase had the potential to replace, in part, both surfactants and zeolite in detergents, and it reduced washing time and allowed washing at lower temperatures under European washing conditions. The marked detergent effect of cellulase on naturally soiled cotton fabric was visually apparent, and it inhibited the accumulation of ash, calcium, and other inorganic components on cotton fibers during wash-and-wear cycles. These contributions of cellulase to the cleanliness of cotton fabrics were clearly increased by repeated wash-and-wear cycles. Cotton fabrics were not degraded by washing with the cellulase because effective hydrolysis by the cellulase occurred only in the amorphous regions of cotton fibers.     

Dyeing characteristics of a Tencel alloy fibre

The exceptional characteristics of Tencel have been modified by incorporating poly(ethylene terephthalate) during solvent spinning, giving the novel Tencel alloy. The present work involved studying the dyeing characteristics of Tencel and Tencel alloy using a range of multifunctional reactive dyes. The fibrillation properties of the fibres was also investigated. Scanning electron microscope studies were carried out to observe the degree of fibrillation of these fibres after wet treatment. Optical microscopy was also carried out to confirm the absence of ring dyeing in fibres dyed using the padding technique.     

Effects of shear rate,viscosity ratio and liquid crystalline polymer content on morphological and mechanical properties of polycarbonate and LCP blends

Studies were conducted on the effects of shear rate, viscosity ratio and liquid crystalline polymer (LCP) content on the morphological and mechanical properties of polycarbonate (PC) and LCP blends. The LCP (LC5000) used was a thermotropic liquid crystalline polymer consisting of 80/20 of parahydroxybenzoic acid and poly(ethylene terephthalate) (PHB/PET). The viscosity ratio (viscosity of LCP: viscosity of matrix) was varied by using two processing temperatures. Due to the different sensitivity of materials to temperature, variation in the processing temperature will lead to varying viscosity of the components in the blends. Based on this principle, the processing temperature could be manipulated to provide a favourable viscosity ratio of below unity for fibre formation. To study the effect of shear rate, the flow rate of the blend and the mould thickness were varied. The shear rate has a significant effect on the fibrillation of the LCP phase. The effect was more prominent when the viscosity ratio was low and the matrix viscosity was high. At 5 wt% LCP, fibrillation did not occur even at low viscosity ratios and high shear rates. It was also observed that the LCP content must be sufficiently high to allow coalescence of the dispersed phase for subsequent fibrillation to occur. © 2002 Society of Chemical Industry