Evaluating the surface characteristics of fibres by compression method

During the recent years, there have been significant developments in methods and philosophies of fibre testing. While it is possible to measure the most of the properties of fibres, there are no standard test techniques for assessing the surface properties of fibres. This research aimed at establishing a technique, which can be routinely used to determine the frictional characteristics of textile fibres. The intention was to assess the frictional characteristics from measurements carried out on fibre ‘bundles’ rather than individual fibres since this should lead to information that is more meaningful in the prediction of processing performance and quality. The technique adapted is based on a sensitive compression test. Developing a technique for assessing the stick-slip characteristics of fibres can be used by cotton suppliers and spinners to provide data that can be used to optimise bale selection and to indicate fibres that may present processing difficulties. This will result in possible improvements in yarn and fabric quality at relatively low cost of fibre testing.     

CCD摄像传感器在纺织上的应用

介绍了CCD摄像传感器的工作原理和性能特点,通过例举清棉机异形纤维检测装置、梳棉机棉结数量检测装置、粗纱机恒张力自动控制装置、自动纱线综合测试仪、光电式条干测试分析仪和棉纤维测试仪等典型实例介绍了CCD摄像传感技术在纺织工业上的应用情况,指出光机电一体化是未来纺织机械的发展方向。     

Improved Methods of Determining Fibre Density

An account is given of an investigation of the effects of fibre type (rayon, acrylic fibre, wool, and cotton) and dimensions on the properties of needled fabrics, the test methods used being those described in a previous paper. Some fabrics show a stick-slip behaviour in extension; others deform smoothly. Rayon webs consolidate more easily on needling than Courtelle or wool webs. Longer fibres give higher fabric strengths. Finer fibres also give higher strength, unless fibre damage occurs. The influence of fibre friction is discussed.     

50—SOME EXPERIMENTS ON THE FRICTION OF COTTON FIBRES

Some experiments on various aspects of the friction of cotton fibres are discussed in the light of their relevance to the processing of cotton. The topics covered include the friction of raw cotton, friction in fibre blends, fibre friction during twisiting, and friction in chemically treated fibres.     

A micromechanical model for extension of a tightly packed bundle of aligned short fibres

Micromechanical models for the interaction between discrete short fibres in idealized bundles are developed and are used to investigate fibre strain profiles, slippage behaviour with increasing extension, bundle load-extension, and tangent stiffness properties. The modeling approach permits abutting fibres to interact by elastic surface shear forces in gripping regions and inelastic frictional slip in slipping regions, where transition from gripping to slipping at a contact position occurs as a linear elastic–perfectly plastic function of the interfibre relative displacement. Results show that for typical staple fibre dimensions and physical properties, a short fibre composite model for the fibre strain profile provides a good approximation to the average fibre strain profile occurring along fibres embedded in bundles. For one fibre assembly considered, results for bundle tangent stiffness indicate that, with increasing extension, average bundle stiffness may be expected to decrease from about 0.8 to 0.5 relative to a bundle of similar but continuous fibres, with 0.5 being reached at the point of collapse by localized slippage.     

Cotton in the new millennium: advances,economics, perceptions and problems

Cotton is the most significant natural fibre and has been a preferred choice of the textile industry and consumers since the industrial revolution began. The share of man-made fibres, both regenerated and synthetic fibres, has grown considerably in recent times but cotton production has also been on the rise and accounts for about half of the fibres used for apparel and textile goods. To cotton’s advantage, the premium attached to the presence of cotton fibre and the general positive consumer perception is well established, however, compared to commodity man-made fibres and high performance fibres, cotton has limitations in terms of its mechanical properties but can help to overcome moisture management issues that arise with performance apparel during active wear.

This issue of Textile Progress aims to:

1. Report on advances in cotton cultivation and processing as well as improvements to conventional cotton cultivation and ginning. The processing of cotton in the textile industry from fibre to finished fabric, cotton and its blends, and their applications in technical textiles are also covered.

2. Explore the economic impact of cotton in different parts of the world including an overview of global cotton trade.

3. Examine the environmental perception of cotton fibre and efforts in organic and genetically-modified (GM) cotton production. The topic of naturally-coloured cotton, post-consumer waste is covered and the environmental impacts of cotton cultivation and processing are discussed. Hazardous effects of cultivation, such as the extensive use of pesticides, insecticides and irrigation with fresh water, and consequences of the use of GM cotton and cotton fibres in general on the climate are summarised and the effects of cotton processing on workers are addressed. The potential hazards during cotton cultivation, processing and use are also included.

4. Examine how the properties of cotton textiles can be enhanced, for example, by improving wrinkle recovery and reducing the flammability of cotton fibre.

     

Upcycling of waste textiles into regenerated cellulose fibres: impact of pretreatments

Abstract

Due to several factors including textile waste accumulation and the use of environmentally harsh chemicals, the textile industry has become the second worst polluting industry worldwide. Therefore, significant effort is currently underway to find solutions to reduce this impact. In this study, coloured waste cotton fabrics were regenerated through a wet spinning process into new coloured fibres, hence recycling not only the fibre materials but also the colour. The impact of pretreatments on the colour retention and degree of polymerization of waste cotton-based fabrics was investigated in terms of the degree of polymerization of the waste cotton, the rheological properties of the spinning dope and the ability to maintain the original colour of the waste fabric. The spun fibres showed mechanical strength similar to commercial viscose fibre. The colour from the original fabric was retained under selected acid pretreatment conditions.     

Structure of Naturally Coloured Cottons

Previous work on the morphology of naturally coloured green cottons has suggested that the secondary wall of the fibres consists of alternate layers of cellulose and a waxy organic substance called suberin. The work described in this paper has shown that modem varieties of green cotton do contain a large proportion of suberin. Data from fibre swelling is consistent with alternate layers of suberin and cellulose in the secondary wall. The naturally coloured fibres have a lower tenacity and work of rupture than conventional white fibres although they have an acceptable level of textile properties. The crystallinity of the coloured fibres is lower than of white cotton, but the cellulose has the Cellulose I structure normally found in cotton.     

15—SOME ASPECTS OF FRICTION IN ROTOR-SPINNING

The effects on yarn properties, fibre arrangements in the yarn, and fibre surface of changes in the frictional forces at some of the most important points in the rotor-spinning machine are examined. Yarn tenacity, CV% of breaking load, elongation at break, regularity, and hairiness were found to deteriorate when the friction was increased at any one of these parts, and the disorder of the fibres increased. Excessive friction on the collecting surface or in the doffing tube caused damage to the fibre surface.     

纤维及其制品摩擦性能测试方法的研究进展

为有效解决纤维及其制品在生产过程中的摩擦问题,提升产品综合性能,对现阶段纤维及其制品生产及使用过程中因摩擦引起的常见缺陷、摩擦性能研究背景及研究价值进行了介绍。阐述了点接触型、线接触型和面接触型纤维及其制品摩擦性能测试方法,分析了不同研究方法的特点、适用范围及其最新进展,并对纤维摩擦性能部分研究成果进行总结。分析认为：纤维及其制品的摩擦性能研究涉及多学科交叉,需加强纤维及其制品微观接触模型及摩擦性能表征方式、与纺织工艺相匹配的测试方法及测试精度提升等方面研究,同时需要纺织、机械、材料和数学等学科人才团队协同创新来推动纤维及其制品摩擦性能的研究进展。     

Investigating hair properties relevant for hair 'handle'. Part I: hair diameter, bending and frictional properties

The expert working group 'Hair Care Products' of the DGK currently conducts a wide study to contribute to the understanding of how single hair fibre and hair collective properties contribute towards hair 'handle' and 'feel'. During the first stage of this study four hair types were selected from a large group of individual European hair braids, according to either similar or widely different panel ratings for handle. Against the background of the panel test and the state of the literature the working group readily identified the bending properties of single fibres interacting in the tress as a fibre collective and fibre friction as being of central relevance for hair 'handle' and 'feel'. Fibre diameters of the hair types were determined by Optical Fibre Diameter Analyzer and by weighing. From these data mean ellipticity and bending stiffness distributions were calculated. Single fibre friction was determined by the capstan method in the root, middle and tip regions. Significant differences were determined between the hair types in diameters, ellipticity, bending stiffness and friction. The results lead to conclude that 'handle' is perceived as inferior when the hair is thick and bending stiffness thus high. For such hair differences in handle rating are related to differences in friction, namely in the tip region. For thin and thus 'soft' hair fibre friction seems to play only a minor role.     

织物含水率对其湿摩擦性的影响

织物的摩擦性能在一定程度上可以间接地反映其刺痒感和湿黏感。选用4种不同规格的聚酯/棉/麻混纺织物,利用FTT织物触感仪对织物进行动摩擦性能测试,通过调节织物含水率,模拟不同的湿度环境,研究织物在被汗液或雨水浸湿后表面动摩擦因数的变化。结果显示:织物含水率较小时,织物的动摩擦因数随着织物含水率的增加而呈现先增大后减小的趋势,织物刺痒感和湿黏感先增强后减弱;织物经、纬向摩擦性能由于织物密度不同而有所差异;当纱线中聚酯含量一定时,不同混纺比的聚酯/棉/麻织物摩擦性能的差异和规律并不明显。     

纺织用不锈钢纤维轴向压缩性能

文章介绍了不锈钢纤维的基本特点和应用,通过实验分析了不锈钢纤维的轴向压缩性能,得出了通常情况下,由集束法生产的12μm以下的纤维不会对人体皮肤产生刺痒感,完全可以满足纺织服用要求。     

18—THE EFFECT OF HUMIDITY ON THE PHOTOTENDERING OF UNDYED FIBRES

Various undyed textile fibres exposed to the Light-fastness Tester under different humidity conditions are shown to lose tensile strength to different degrees; poly(vinyl alcohol) fibre, viscose, nylon, and cotton are found to be very sensitive to changes in humidity, whereas Orion acrylic fibre and Terylene polyester fibre are the least sensitive materials among those tested.     

A comparative study on properties of dual-core yarns

Core-spun yarns containing Spandex have been widely used for the production of elastic textile materials. However, it has been encountered various problems not only during the usage but also during textile processes due to its high recovery property. In order to solve these problems, multicomponent core-spun yarns called as dual-core (DC) yarns, have been developed. DC yarns can be produced on the modified ring spinning machine in two different ways. In the first method, previously combined two core yarns are fed simultaneously, whereas in the second method, two core yarns are given separately into the centre of sheath fibre bundle. In present study, it was aimed to research the effect of these production methods on yarn features. Polyester and Spandex core components and cotton wrapping fibres were brought together in both two ways and the properties of multicomponent core-spun yarns were compared with cotton ring counterparts for three different yarn counts.     

The Shedding Propensity of Fabrics

A model of the disentangling of two twisted fibres by a combing pin is presented. It has been postulated that the pin engagement initially increases the twist level and develops torque in the twisted structure in a way similar to the torque generation in the twisting of textile cords. If the pin speed is not too high, the torque thus developed is able to untwist the fibres without breaking them, provided that the twisted sector is relatively free to rotate. Otherwise, the helix angle of the twisted structure increases very sharply towards its geometrical limit, leading to the inevitable consequences of fibre breakage because of buckling or snarling of the twisted structure.

The various mathematical formulae derived from this model can be used to predict the threshold pin-speed value below which fibre breakage could be avoided. They can also be used to examine the effects on fibre breakage of different parameters such as initial twist level, fibre length, fibre physical properties, etc. The effects of other processing variables, such as fringe density, pin geometry and friction, etc., can also be inferred from this model.     

The Friction of Polyester Staple Fibres: The Effects of Speed,Processing, Spin Finish,Humidity, and Counterface-surface Roughness

Experiments are described in which a capstan method was used to measure the fibre/metal and fibre/fibre coefficients of friction of single polyester staple fibres. Tests were conducted on fibres carrying the manufacturer's spin finish, before and after partial processing into yarn, and on cleaned fibres. The cleaned fibres were tested against stainless-steel pins of roughness 0.08, 0.11, and 0.28 μm R_A, in atmospheres of 65% and below 20% relative humidity. All the tests were conducted over the speed range 0.03–290 m/min.

The spin finish is shown to have an increasing effect with processing of the fibres and is thought to be unevenly distributed in the hale fibre. The friction of cleaned fibres shows more correlation with the mechanical properties than with the delustrant content. Fibre/metal friction is lower against the rougher surfaces owing to variations in the true area of contact. Humidity affects the low-speed fibre/metal coefficients, which may indicate the presence of adsorbed-water layers on the metal surface at high humidity.     

The sol-gel technology application of cotton textile processing

In this research, pure cotton textile was modified by the sol-gel technology with low thermal post-treatment temperatures: drying at 90 °C for 10 min after curing at 120, 140 and 160 °C for 2 min. The impact of the cotton textile coating by sol-gel technology, different curing temperatures and multiple washing cycles to the adhesion of the coating, textile air permeability and abrasion resistance were studied. The morphology changes of the cotton textile surface before and after coating, and after multiple washing cycles were evaluated by scanning electron microscopy. The sol-gel treatment can impart antibacterial properties to the textile against Pseudomonas aeruginosa and Staphylococcus epidermidis, by the reduction of the bacteria adhesion with the cotton textile. All test results evince about a very good coating containing Zn and Si adhesion with cotton textile fibres..     

Influence of spinning parameters on milkweed/cotton DREF-3 yarn properties

In this study, Pergularia milkweed fibre (70%), cotton fibre (30%) core and 100% cotton fibre sheath DREF-3 core yarns of 74?tex were produced using different spinning parameters in order to understand their effect on yarn properties. Box–Behnken design was used for the optimization of core ratio, drum speed and suction pressure, and to evaluate the effects and interactions of the process variables on the yarn properties at a constant opening roller speed of 12,000?rpm and production speed of 100?m/min. The effects of the core/sheath ratio on all the yarn properties are significant. With an increase in the core/sheath ratio, yarn tenacity and elongation decrease due to insufficient wrapper fibres in the yarn and yarn unevenness; imperfection increases due to higher feed rate and draft at higher core ratio. The yarn hairiness increases at higher core ratio due to higher number of short fibres in milkweed and lesser sheath fibres to cover the core fibres effectively. An increase in the spinning drum speed damages fibre in the sheath and increases the number of hooks at the end of fibres, as a result of which the core yarn tenacity decreases at higher drum speed. At a higher air suction pressure, yarn tenacity and the elongation at break increases. The drum speed and suction pressure have no significant effect on yarn unevenness and imperfections. The yarn hairiness decreases slightly with increase in drum speed and suction pressure but is insignificant.