Strengths of Twisted Blend Fibrous Structures: Theoretical Prediction of the Hybrid Effects

Hybrid structures have been applied in many areas such as textiles and composites. However, the mechanisms giving rise to the advantages associated with fiber blending, presumably due to the interactions between constituents of different types, are still poorly understood. This work is an attempt to look into the internal interactions through theoretical analysis. A twisted structure (yarn) of two distinct fiber types with statistically distributed strengths is studied. It has been established in yarns of the single fiber type that the interaction via friction between fibers will lead to a substantial increase of fiber effectiveness, and consequently the yarn strength. Incorporating this concept into the present hybrid case makes it possible to more accurately predict the strength and its distribution for the blended yarn. Moreover, it is revealed in this study that the interaction between fibers prior to the initiation of yarn failure may be the most important factor which causes the so-called hybrid effects. Predictions of the hybrid effect are provided and the influences of relevant factors are discussed in this paper.

Although the present work is targeted at hybrid yarn structures, the conclusions drawn herein are in principle applicable to hybrid fiber composites as well.     

Geometry of fiber distribution in Marl yarn using the computational method

In this research, the structure of a type of bi-component composite yarns so called Marl yarn was studied. Fibers packing density factors within the yarn cross section as well as the effect of twisting on the resultant yarn were investigated. Samples of Marl acrylic yarns were provided using different twisting levels. Images of the cross sections of the produced yarn were obtained using the transverse sectioning method. The images were captured using the optical microscopy. The prepared images of the yarn cross section were then analyzed using image processing methods. In the first stage, yarn central coordinates and radiuses were calculated. In order to investigate the uniformity of fibers distribution and packing density within the yarn cross section, the fiber distances from the yarn center within the small radial and polar elements were calculated and the coefficient of variations (CV %) was determined. The maximum value of the fibers packing density was determined. The results showed that the fibers were mostly concentrated within the central region of the yarn; this was followed by the decrease in the fibers packing density while moving into the yarn’s outer layers. It was also concluded that increasing the intensity of the applied twist would result in higher fibers packing as well as the decrease in the yarn radius.     

加捻方向对双股线性能的影响

加捻是制备短纤纱、股线及绳索的必备工序。加捻对纱线有两方面作用,一是通过加捻增加纤维间的抱合力,从而赋予纱线足够的强度。二是加捻增加了纤维间的螺旋角并使纤维集聚在一起,从而增加纱线的强度。采用意大利Savio公司的Sirius倍捻机制备不同捻向的双股线试样。尝试验证不仅捻度对纱线性能有重要的影响,而且纱线捻向也有很大的影响。测试结果表明,捻向与单纱捻向相同的双股线(单向捻合双股线)具有更好的断裂强力、断裂伸长率、摩擦因数与耐磨性。研究还给出了捻向对双股线及由双股线制成的织物拉伸性能的影响。     

摩擦纺荨麻包芯纱的纺制及工艺研究

荨麻纤维是一种野生的天然纤维,属于麻类纤维的一种,目前国内外对荨麻纤维的开发和利用还处于起步阶段.分析了荨麻纤维的可纺性,开发出了以荨麻纤维和亚麻短纤维为包覆纤维、涤纶短纤维为芯纱的摩擦纺包芯纱,并利用正交试验,研究了纺纱速度、摩擦辊转速以及芯纱比例对纱线性能的影响,优选出荨麻纤维摩擦包芯纱的纺纱工艺范围.     

具有改进弹性回复性能的车用杂化聚酯长丝纱

本项目旨在开发具有改进弹性回复性能的汽车织物用杂化聚酯长丝纱。众所周知,PBT长丝纱比纯PET纤维长丝纱具有更优良的弹性回复性能。当然,也有许多替代品,如氨纶包聚酯和PET/PBT双组分纤维等。对PET/PBT适当组合研发空气喷射变形丝的工作进行了概述,目的是研发一种PET/PBT长丝纱,以便生产一种杂化长丝纱。为满足...     

Dual-feed rotor spinning of cotton fiber: trash separation and yarn properties

In all industrial rotor spinning machines, opening of the fibers is performed by an opening roller, in which sliver is fed from a single point. Increasing number of feed rollers from one to two may improve fiber opening and trash ejection by two-step loading in opening zone of the opening roller. This may improve fiber orientation and blending in the produced yarn and yarn properties. In earlier two sliver feed laboratory systems (dual-feed), it was not possible to work with cotton fiber, because the trash removal zone was used for feeding a second sliver. The aim of this study was to design a system that can take advantage of dual-feed and also extract the trash. The experimental rig was a modified RU04 rotor spinning unit of Rieter in which two separate sliver feed systems were utilized. Raw material used and yarn count were cotton and 29 tex, respectively. Extracted trash and yarn properties produced with dual-feed system were compared with that of the original unit. Yarn properties tested were tenacity, extension, work of rupture, mass irregularity and imperfections, hairiness, and abrasion resistance. Test results were analyzed by ANOVA for any difference between the means and Duncan for ranking. Tenacity, strain at peak, work of rupture, and yarn abrasion of the dual-feed yarn increased, and their mass irregularity and imperfections decreased in comparison to that of the conventional yarn. According to the test results, it was concluded that, increasing number of feed rollers on the opening roller from one to two has improved the yarn properties and trash separation of cotton fiber is possible and comparable to the original single feed.     

喷气纺普通聚酯纱与超细聚酯纱的结构与弯曲性能研究

对由普通与超细聚酯纤维纺成的村田喷气纺纱线的结构进行了研究和比较。用带有数码相机的光学显微镜进行纱线的结构研究。由拍摄的照片可得到很多纱线结构参数,如纱线正常区域的直径、包覆区域的直径、纱线中心处纤维的螺旋角、纱线表面纤维的螺旋角、被包覆纤维包覆的包覆区域的长度、包覆纤维包覆的区域、包覆区域纱线的弯曲刚度等。结果表明:由超细纤维纺纱制成的纱线的弯曲刚度比普通纤维的弯曲刚度低;纤维类型影响包覆摩擦因素以及纤维包覆区域;由超细纤维纺成的纱线的直径比普通纤维的小。     

Simulation on fiber random arrangement in the yarn part II: joint effect of fiber length and fineness distribution

Simulation on fiber random arrangement in the yarn has been studied in our previous research, where only fiber length distribution was considered. In this study, fiber fineness distribution was also taken into account in order to study the joint effect of fiber length and fineness distribution on fiber arrangement in the yarn. Eight-millimeter term limit irregularity of simulated yarn can be re-expressed by calculating the irregularity of the total weight of fibers within each yarn subsection. It can be seen from the results that the calculated irregularities considering fiber fineness distribution are closer to tested values compared with those without considering fiber fineness distribution. Besides, when the variance of fiber fineness gets greater, the difference between the calculated values with and without considering fiber fineness distribution becomes more obvious. For fiber length, the effect of average fiber length on yarn limit irregularity is very little, while its distribution has no significant effect on yarn limit irregularity. The improved simulation on fiber random arrangement in the yarn is more reasonable and can be applied for the prediction of yarn qualities.     

纽代尔/圣麻/棉超深蓝牛仔布的生产工艺

探讨了纽代尔/圣麻/棉超深蓝牛仔布的生产工艺.结合3种纤维的特性进行不同混比的纺纱试验,然后,对混纺纱进行染色、织造、整理等工艺研究,确定合理的工艺参数,提高了产品质量.     

Hibiscus sabdariffa (Roselle): A potential source of bast fiber

Roselle is a bast fiber, and its utilization as a textile fiber for the development of textile products is still scanty. A work has been attempted to develop yarn from Roselle. Fibers were extracted from Roselle bark by decortication and degummed in alkaline medium. The degumming process was optimized based on fiber yield and strength. The degummed fibers were then bleached by the hydrogen peroxide bleaching process. Degummed and bleached fibers were characterized by scanning electron microscope, Fourier transform infrared spectroscopy, and X-ray diffraction analysis. Degumming and bleaching results in enhancement of density, fineness, and brightness of Roselle fiber. A marginal decrease in tenacity of the Roselle fiber was observed after bleaching; however, the strength was not affected by degumming. Fibers were converted into fine yarn in the jute spinning system. The yarn properties inferred that the yarn possessed essential properties for the preparation of apparels and home furnishing.     

Investigation on production,analytical models,and characteristics of monofilaments/staple fibers composite yarn

This study aims to develop a composite yarn comprising monofilaments/staple fibers with distinctive structures and performance. A modified ring spinning system was proposed for producing the composite yarn with three monofilaments and staple fibers. The spinning mechanism was analytically modeled, and the structures of composite yarn were studied by scanning electron microscopy and optical microscopy. The characteristics of polyester monofilaments/cotton composite yarns and the conventional cotton yarns were compared. Analytical and experimental results showed that three monofilaments were distributed around the yarn center forming a 3D spiral, and the staple fibers interlaced inside and wrapped outside of the composite yarn. Experimental results showed that the composite yarn had better tensile properties, less hairiness, and stronger abrasion resistance. As a result, the composite yarn exhibited a remarkable improvement over the conventional yarn, which could be a valuable proposition for specific purposes, such as offering fabrics with shape preservation based on good yarn’s rigidity, and even electromagnetic shielding effectiveness with metal monofilaments in yarns.     

Influence of Friction Spinning Process Parameters on Spinnability of Pergularia/Cotton-Blended Yarns

In this study, spinnability of Pergularia daemia seed fiber (70%) and cotton fiber (30%) core/100% cotton fiber sheath DREF-3 core yarns of 74 tex were studied 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 delivery rate of 100 m/min. The effect of the core/sheath ratio on yarn quality index is significant. With an increase in the core/sheath ratio, yarn tenacity, and elongation decreases due to insufficient wrapper fibers in the yarn and yarn unevenness increases due to higher feed rate and draft at higher core ratio. An increase in the spinning drum speed increases the yarn quality index up to certain range and then decreases at higher speed due to damaging of fibers in the sheath and more number of hooks at the end of fibers. At a higher air suction pressure, yarn tenacity and the elongation at break increases which ultimately increases the yarn quality index. From the regression analysis, it is observed that the drum speed and suction pressure has no significant effect on yarn unevenness.     

和毛油添加对牦牛绒纤维及成纱质量的影响

针对牦牛绒纤维长度离散性大、纤维之间不易抱合而导致成纱困难的问题,采用和毛油对牦牛绒纤维进行处理,以提高纤维的可纺性。为此,本文分别对经过和毛油处理和未经过和毛油处理的相同线密度的牦牛绒纤维的表面结构形态、纤维拉伸性能、表面摩擦性能、回潮率以及纱线性能等性能测试,结果表明：经过和毛油处理的牦牛绒纤维表面鳞片清晰,并且透光均匀,鳞片翘角与未经过和毛油处理的相当,强力、断裂强度、断裂伸长率、断裂功均较好,动、静摩擦系数与差微摩擦效应较小,回潮率较高;同时,经过和毛油处理的牦牛绒纤维所纺制的纱线的各项性能均有所提升,尤其是纱线的条干均匀度较优,粗、细节和棉结较少。     

特殊外观结构赛络花式纱的后区牵伸及成纱结构分析

为开发新型花式纱,在细纱机上采用刻有凹槽的后罗拉上胶辊纺制赛络花式纱。分析了此花式纱用胶辊对后钳口须条的受力及成纱结构,在TH598J细纱机上采用切断称重法测得胶辊转动1周从中罗拉输出的须条的质量分布,分别得到正常胶辊和花式纱用胶辊输出须条的质量分布,并由牵伸倍数公式分别获得正常胶辊和花式纱用胶辊的后区牵伸变化曲线,同时对成纱线密度进行分析,从而探究此花式纱的成纱外观结构变化。结果表明:刻有凹槽的胶辊使得后区牵伸倍数由正常逐渐降为1再逐渐增大到正常,通过凹槽的这段须条对其前后一段须条的牵伸产生影响,使之牵伸倍数从正常开始减小,从而使成纱线密度也呈现增减变化,获得了一种特殊外观结构的赛络花式纱。     

纱线条干不匀的随机模拟

 纤维随机排列的描述是研究纱线不匀理论的关键。给定一个纤维长度分布,如果假设纤维头端在纱线长度方向服从均匀分布,便可以建立理想纱条中纤维排列的几何模型。采用Monte Carlo方法模拟了这个理想纱线截面纤维根数的变化。在纱线的几何模型中,还使用8毫米的检测区域模拟了电容式条干仪的检测结果。通过比较说明,在纤维随机排列的前提下,随着纱线支数的增大,纱线模拟检测 值必然按照某个规律增大,理想纱条的截面纤维根数渐近服从正态分布,纱线截面的纤维根数变异与模拟检测的区间上纤维量的变异相关性不够显著。纱线实测数据说明了模型的有效性。     

纱线断裂功对经编织造性能的影响

为深入了解经编织造对纱线力学性能的要求,结合纱线张力及断裂功,提出用纱线断裂功来评价纱线经编织造性能的观点。选择集聚纺14. 58 tex 长绒棉棉纱、集聚赛络纺9. 72 tex 棉纱及8. 33 tex(72 f)涤纶丝为试样进行经编织造,测试其张力及纱线拉伸断裂性能。将3 种纱线张力测试数据进行角度域转化,计算单循环内纱线张力做功,再结合纱线断裂功进行分析。结果表明：棉纱和涤纶丝张力随主轴变化趋势相同且波动程度差别较小;棉纱张力做功接近纱线断裂功,而涤纶丝张力做功远小于其断裂功;纱线张力做功与纱线断裂功之间差值越大,纱线经编织造适应能力越强。     

全聚纺涤棉混纺纱内纤维的径向分布

为研究全聚纺混纺纱中纤维的径向分布情况,采用环锭纺、网格圈型集聚纺和全聚纺3种方法纺制28.1tex涤棉混纺纱线,运用哈氏切片器切取三种混纺纱线样本,借助MOTTC B1型显微镜观察并采集样本中两种纤维的分布状况图,结合汉密尔顿（Hamilton）指数的方法分析,得到全聚纺混纺纱内涤纶纤维和棉纤维在纱截面内的内外转移趋势及分布规律。结果指出：利用传统环锭纺纺制的涤棉混纺纱,涤纶纤维有明显向纱芯转移的趋势,而网格圈型集聚纺,涤纶纤维向纱芯转移的趋势较传统环锭纺弱,全聚纺相对于网格圈型集聚纺而言,涤纶纤维分布更加随机,并且涤纶纤维有向纱外转移的趋势。     

捻度对棉/氨纶/银丝包芯纱性能的影响

为了制备具有良好纺织特性的弹性导电纱线材料，以棉粗纱、氨纶、银丝为原料，通过设计原料的喂入方式及在环锭纺纱机的前罗拉与导纱钩之间附加定位装置，纺制以氨纶为纱芯、银丝与棉纤维螺旋包缠氨纶且棉纤维位于纱线表面的弹性导电包芯纱，探究捻度对纱线弹性、导电性、耐磨性和断裂强力的影响。以银丝紧贴氨纶表面包缠为模型，计算得到不同捻度下包芯纱中紧贴氨纶表面包缠的银丝长度的理论值。实验结果表明：包芯纱的弹性随捻度变化，在70捻/(10 cm)时包芯纱定伸长伸长弹性率、定负荷伸长弹性率较大；在包芯纱伸直(不伸长)状态下，纱线实测电阻值随捻度的增大而增大；在包芯纱伸长10%的状态下其实测电阻值小于伸直状态下等长度包芯纱实测电阻值，且在75捻/(10 cm)时伸长状态与伸直状态下的相同长度包芯纱的实测电阻值之差较小。     

Research on fiber distribution in front draft zone of super high draft ring spinning based on cut-middles method

A super draft ring spinning machine was designed to spin high-count cotton yarns. It was equipped with four-line draft system (FLDS) and four aprons. For yarns spun on FLDS, it often occurs that yarn unevenness increased compared with three-line draft system (TLDS). In the paper, by cut-middles method, the fiber distribution in front draft zone of FLDS draft system was studied, and corresponding yarn qualities were analyzed. First, comparison analysis of yarn quality between FLDS and TLDS was presented. Cotton yarns of 9.7 and 7.3 tex were spun by TLDS and FLDS ring spinning machine, respectively. The results shows that for 9.7 tex cotton yarn, slower fibers in yarns spun on FLDS are more than that in yarns spun on TLDS. For FLDS, the friction field at the back of front draft zone is stronger, which improves yarn evenness. However, for 7.3 tex cotton yarn, accelerated point of fibers on FLDS is nearer to nipper bite of front roller than that on TLDS. Thus, evenness of yarns spun on FLDS is better. Then, 4.9 tex cotton yarn was taken as an example, and they were spun by four kinds of draft distributions on FLDS. The results indicate that for 4.9 tex cotton yarns spun by 64.1 × 1.60 × 1.15, slower fibers at the back of front draft zone are mostly found. And accelerated point of fibers is nearest to nipper bite of front roller. Therefore, 4.9 tex cotton yarns spun by 64.1 × 1.60 × 1.15 have best yarn evenness.     

壳聚糖载银抗菌纱的制备及性能初探

涤纶丝广泛用于抗菌纱和织物的制备。近年来,许多抗菌物质逐渐商业化,替代抗菌物质已成为抗菌纱加工研究的重要目的。大多数抗菌物质是通过直接浸泡或涂层的方式加载在抗菌纱上的。研究旨在通过二浸二压的纺织品整理工艺,将壳聚糖载银溶液固定到涤纶纱线上。通过扫描电子显微镜分析了纱线涂层前后结构的变化,并测试了其对金黄色葡萄球菌和大肠埃希菌的抗菌性能。试验结果表明,经壳聚糖载银溶液涂层处理的涤纶纱线均具有较好的抗菌性能,且试样R-3具有更优的抗菌效果。