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.     

32—A USEFUL METHOD FOR CALCULATING COEFFICIENTS OF FRICTION OF WOOL FIBRES FROM CAPSTAN MEASUREMENTS

An account is given of an investigation in which a variant of the capstan method was used to study the dependence of the frictional properties of wool fibres on the tension in the fibres when they slid at a very low speed over a rod of horn immersed in water (to which a wetting agent had been added). Some ofthe fibres had been given a mild shrinkproofing treatment with KMnO₄ in saturated salt solution. The curves relating the tensions T ₁ and T ₀ in the two ends of a sliding fibre, with T ₁ > T ₀, were found to be accurately linear in the range from T ₀=O up to T ₁=05 gf. For with-scale sliding, they all passed very close to the origin, but nevertheless the coefficient of with-scale friction,μ_w(={1/π}ln{T ₁/T ₀}), was markedly dependent on the tension owing to the high sensitivity of the logarithm to ‘zero error’ in the range of T ₁/T ₀ appropriate to with-scale sliding. For against-scale sliding, the intercept was larger and more variable, so that μ_a also depended markedly on the tension. It is suggested that the most satisfactory parameters to use for characterization of the friction are the coefficients of friction calculated from the slopes of the curves of T ₁ against T ₀, without regard to the intercepts.

It is shown that these new parameters reveal satisfactorily a previously determined difference between the shrinkproofed and the untreated fibres, namely, that the with-scale coefficient is significantly larger for the shrinkproofed fibres.

The measured coefficients for untreated fibres depend on the state of polish of the horn surface. For treated fibres, repolishing the horn greatly increases the variance of the measurements. The best conditions to use for particular applications are dicussed.     

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.     

竹浆纤维兔毛绢丝混纺针织纱的研制

为了顺利纺制竹浆纤维/兔毛/绢丝50/30/20 18.2 tex混纺针织纱,针对3种原料的性能特点,进行了纺纱工艺试验。结果表明:竹浆纤维可纺性较好,采取开清棉工序单独成条;兔毛、绢丝静电现象严重,需进行预处理,经和毛机混和后再经梳棉机成条;采用三道并条混和,工艺配置采用重加压、大隔距;粗纱、细纱工序采用重加压、大捻度、低速度工艺;生产中要合理控制温湿度,防止纤维缠绕机件。     

Improved function of bamboo shoot fibre by high-speed shear dispersing combined with enzyme treatment

With the increase in global welfare, metabolic syndrome-related diseases seriously disrupt our quality of life. Balanced diet with low calories, low glycaemic index, and high dietary fibre such as bamboo shoot fibre is needed. Functional properties of dietary fibre can be improved by processing methods. Therefore, we compared the effect of three processing methods (high-speed shear dispersing, enzyme treatment and combined treatment) on the characteristics and functions of bamboo shoot fibres. Combined treatment resulted in high SDF content (10.15%), adsorption capacity of glucose (4.45–18.18 mmol g⁻¹), nitrite ion (505.49 μg g⁻¹ [pH 2.0]), and cholesterol (333.72 μg g⁻¹ [pH 2.0]). FTIR revealed that hydroxyl groups, sugar methylene and benzene rings of aromatic compounds existed in the treated bamboo shoots. The particle size (D₅₀) decreased from 383.90 to 30.65 μm. Honeycomb-like structure was also observed through SEM. Thus, proper processing of bamboo shoot fibres can improve their functions as food ingredients.     

Physico-chemical properties of black yak fibre and its modification for blending with jute fibre

Coarse yak fibre remained underutilized due to its higher stiffness, lower co-efficient of friction, and deep black in color. Such fibre was chemically modified to change its color similar to jute fibre. After modification the co-efficient of friction improved to 0.368 from 0.280 in the untreated sample. The improvement in co-efficient of friction and color increased the acceptability of blending of yak fibre with jute fibre. It was possible to blend 75% yak fibre with jute after suitable modification. Jute/yak fibres blended yarns were converted into plain woven fabrics as weft and polyester spun yarn as a warp.     

Dietary fibres in pulse seeds and fractions: Characterization,functional attributes,and applications

Pulses are a good source of dietary fibre and other important nutrients. Flours and fibre-rich fractions obtained from pulse crops can be incorporated into processed foods to increase dietary fibre content and/or serve as functional ingredients. This review focuses on research conducted in the past ten years on the non-starch polysaccharides and oligosaccharides found in dry beans (Phaseolus vulgaris), chickpeas (Cicer arietinum), lentils (Lens culinaris), and dry peas (Pisum sativum). The isolation, composition, and structure of these pulse fibres are described. Common terms used to describe the physicochemical properties of fibre fractions are defined and briefly discussed. Recent studies on the effects of processing on the ratio of insoluble to soluble dietary fibre and on the α-galacto-oligosaccharide content of pulses and fibre fractions are cited and summarized. Food applications for pulse fibre fractions and flours in fibre enrichment, nutrient enrichment, fat binding and retention, and texture modification, as well as some non-food applications, are reviewed.     

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.

     

Effect of Moisture in Flax Fibres on the Quality of their Composites

Moisture present in plant fibres is considered to be detrimental to the performance of composites. In general, a drying stage is performed on the plant fibre fabrics before manufacturing the composites since it is seemed to allow better output. This work provides an analysis of the effect of moisture in flax fibres on the overall quality of epoxy/flax biocomposites. Flax fibre fabrics were conditioned at different relative humidity (RH) environments and composites were manufactured by vacuum infusion technique. Composites were characterized by mechanical and microstructural analysis. Results showed that manufacturing composites with highly humid fabrics (95% RH) generates post processing deformation of finished parts and also leads to poor microstructural quality. The moisture in the fibres with different RH reduced the stiffness (from 23.74 to 17.67 GPa for Young’s modulus and from 16.28 to 11.82 GPa for flexural modulus) but increased their fracture strain (from 1.87 to 2.64). Tensile strength displayed an optimum value (287.96 MPa) for fabrics conditioned at 50% RH, but flexural strength decreases continuously from 225.12 to 152.34 MPa as the moisture in the fabric increases.     

纤维的抗菌防臭及制菌加工进展

阐述了抗菌防臭、制菌纤维的两种加工方法：纤维混入法和后处理加工法;并对表面活性剂类、有机硅树脂季铵盐类、双胍类、纤维上金属配位类、无机金属离子抗菌剂类、天然抗菌的类等抗菌防臭、制菌加工剂的性能和使用方法作了详细介绍。抗菌防臭和制菌整理是２１世纪四大功能性整理之一,其发展趋势广阔,前任光明。     

More about fibre friction and its measurements

Unfortunately, the classical empirical friction laws do not hold true for fibrous and viscoelastic materials comprising most of the textile fibres. In the second half of the twentieth century, fibre surfaces have been studied by many distinguished scientists who were able to complete numerous researches for the frictional characteristics of different types of fibres. Most of the researchers have aimed to develop a new test method and a test device that can be used to measure the frictional characteristics of fibres quickly, accurately and easily in their studies. Unfortunately, there is not a standard test method or a test device for the measurement of textile fibres' friction properties. For today's competitive marketing, the instrument for fibre testing must be very fast and accurate; otherwise, it will not be useful for commercial purposes. For example, hundreds of thousands of cotton bales should be tested within a very short period of time in terms of the length, colour and trash content of the cotton bales. Without having the data describing the properties of cotton fibres, cotton bales cannot be sold commercially in most of the countries. Therefore, it is an important factor that the fibre-testing instrument should be fast and accurate. Most of the properties of cotton fibres can be assessed by using a HVI fibre-testing instrument. In this review, the historical perspective of fibre friction studies has been demonstrated with the fibre friction measurement-testing devices.     

防辐射纤维及其织物的发展前景

文章介绍电磁波辐射的危害、防护原理以及几种防电磁辐射纤维：金属镀层纤维、金属纤维及碳纤维、涂覆金属盐纤维、复合型高分子电磁屏蔽纤维和r射线防护纤维,及织物的研究现状与发展趋势。指出具有屏蔽电磁辐射功能的纤维及材料具有广阔的应用前景。     

Factorial optimisation of the effects of extrusion temperature profile and polymer grade on as-spun aliphatic–aromatic co-polyester fibres III: mechanical properties

The effect of extrusion temperature profile in the melt‐spinning process of as‐spun linear aliphatic–aromatic co‐polyester (AAC) fibres upon their mechanical properties and process productivity was modelled by using factorial experimental designs. After the viscoelastic and morphology characteristics of the polymer were considered using Differential Scanning Calorimetry and Melt Flow Index (MFI), the rheological data were used to determine the enhanced melt‐spinning temperature of the six heating zones in the process. Tensile strength, elongation at break, modulus and fibre productivity (g/min) of the melt‐spinning process have been quantitatively assessed as responses to polymer grades and extrusion zone temperature. The optimisation of mechanical properties and productivity helps in understanding and controlling the most desired properties in the produced fibre. It has been noted that the die head temperature (spinning temperature), the polymer grade and their interaction are the most significant factors affecting the mechanical properties. Analysis of the fibre productivity shows that the polymer grade and its interaction with the die head temperature is significant in terms of influencing the output of the melt‐spinning process, which could be related to the polymer molecular weight and polymer structure. There is an interaction between polymer grade and feeding zone temperature which is related to the material supply action in the feeding zone. The friction between the screw and the material is affected by heating action, which affects the moisture content and the molten material rheology. By adjusting the extrusion temperature profile and selecting the more applicable spin‐able polymer grade through a statistical forecasting model, the combination of the cost related to material grade and processing cost controls the fibre production cost. The fibre made of low MFI grade has better structure and mechanical properties than that made of the higher MFI grade, and the former will be preferred for future work. With previous work related to the effects of extrusion temperature profile on the fibre structure, the present paper will help in developing the production process of biodegradable linear AAC fibres.     

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.     

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.     

The role of the endomysium in the salt-induced swelling of muscle fibres

Variable uptake of water is a persistent problem in meat processing. To try to understand the changes that occur during water uptake, and thereby explain this variability, we have measured the swelling of salt-treated single muscle fibres from rabbit longissimus dorsi. By dissolving out the myofibrillar proteins with SDS we have been able to tell whether or not a dissected fibre has an endomysial connective sheath. We find that some fibres do lack a sheath and that these stripped fibres swell on average approximately five times more than intact fibres in 0·25 m KI. This shows that the endomysium limits the swelling of the fibre in salt, as is also shown by the greater swelling of those parts of fibres from which the endomysium has been deliberately removed. On prolonged immersion in 0·25 m KI the stripped parts of fibres shrink after swelling whereas the smaller swelling of unstripped parts is maintained. With careful, slow dissection, the proportion of stripped fibres is low at all times post mortem, but if a quicker method is used, the proportion of stripped fibres increases with time post mortem. As ageing proceeds, an increasing incidence of transverse fractures reduces the productivity of the quicker method, so the slow method has to be used. Regardless of the method of dissection the swelling of stripped and unstripped fibres does not depend on time post mortem. Thus it is the changing proportion of stripped fibres that underlies the earlier report (Wilding et al. Meat Sci., 1986 18, 55) of a dependence of swelling on time post mortem. The ease of stripping of endomysium from muscle fibres may be important in meat processing. Thus whether or not fibres produced during comminution and mixing of meat are stripped directly affects water uptake. The extraction of myofibrillar proteins may also be affected, which would be important for the adhesion of cooked reformed meat products.     

Analysis of the effect of experimental parameters on the morphology of electrospun polyethylene oxide nanofibres and on their thermal properties

Electrospinning is a new and simple method of producing nanofibres by introducing electric field into polymer solutions. We perform an experimental investigation on the influence of processing parameters and solution properties on the structural morphology and average fibre diameter of electrospun polyethylene oxide (PEO) polymer solution and on their thermal properties. Experimental trials have been conducted to investigate the effect of solution parameters, such as concentration, addition of ethanol in PEO solution, solvent effect, as well as governing parameters, such as applied voltage, collection distance and flow rate. At higher concentrations, the nanofibres with regular morphology and, on average, uniform fibre diameter were obtained, and at lower concentrations of PEO polymer solution, the fibres showed irregular morphology with large variations in fibre diameter. We also found that the addition of ethanol increased the fibre diameter and produced bead‐free fibres. Applied voltage, collection distance and flow rate also influence fibre morphology. To analyse the thermal properties of the fibres produced from the PEO powder and the electrospun nanofibres produced from the two polymer solutions (PEO + water and PEO + water/ethanol), differential scanning calorimetry (DSC) was used, and to determine the degree of crystallinity, X‐ray diffraction technique has been used.     

Effect of heating–cooling cycle on the opto‐structural properties of low‐density polyethylene fibres using two‐beam interference microscopy

A hot stage attached with a two‐beam interference (Pluta) microscope was used to apply a heating–cooling cycle (HCC) on low‐density polyethylene fibres (LDPE). The variation of the refractive indices (n ^∥ and n ^⊥) with the temperature was carried out during the heating and cooling of the LDPE fibres. The activation energy (E _a) and thermooptic coefficient (dn/dT) were calculated for the investigated LDPE fibres. The spectral dispersion curves, percent crystallinity and orientation function were determined for the treated LDPE fibres. It was found that the HCC for LDPE fibre implies: a reversible behaviour of both optical and structural properties against temperature and an improvement in the fibre crystallinity.     

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.