Structure–property relationship of different types of polyester industrial yarns

Four major types of polyester industrial yarns (1000 Denier) which are used commercially were studied for their key structural parameters. An attempt has been made to establish a relationship between morphology and properties of these yarns. High tenacity (HT) polyester yarn has the highest birefringence, amorphous orientation, and long period but is relatively less crystalline. High shrinkage characteristic of HT polyester yarn can be accounted for its higher amorphous orientation. High modulus low shrinkage (HMLS) polyester yarn has higher crystallinity and crystal size compared to HT yarn. Fraction of tie molecules of these yarns has been calculated and found that low shrinkage (LS) and super low shrinkage (SLS) yarns have lesser tie molecules. These LS and SLS yarns are tailor-made to achieve lower shrinkage and at the same time maintaining a good level of tenacity. This is achieved with lower amorphous orientation in the final drawn yarn structure. Amorphous orientation was found to have stronger influence than any other structural parameter on the key yarn properties like modulus, tenacity, elongation, and shrinkage.     

应用二维X射线衍射法测定涤纶工业丝结晶和取向行为

为确立涤纶工业丝微观结构与力学性能之间的关系,建立一种有效的测试方法至关重要。利用二维X射线衍射法研究了普通高强型（HT）、低收缩型（LS）、超低收缩型（SLS）3 种不同种类涤纶工业丝的晶态结构和晶区取向度,并分析了对其性能的影响。结果表明：干热收缩率最小、尺寸稳定性最好的SLS 型工业丝结晶度和晶粒尺寸最大,但其晶区取向最小;而断裂强度最高、断裂伸长率最小的HT 型工业丝结晶度和晶粒尺寸最小,晶区取向却最大;LS 型工业丝则介于二者之间。综合分析可知,结晶度和晶粒尺寸主要影响涤纶工业丝的干热收缩率,晶区取向度则影响涤纶工业丝的断裂强度、断裂伸长率以及弹性模量。     

工业用涤纶长丝的结构与性能

 采用显微照相系统、差热分析仪、纤维拉伸强力仪、纱线拉伸强力仪、热收缩仪等对3类工业用涤纶丝的形态结构、力学性能、热收缩性能等进行测试分析。结果表明：高强型(HT)涤纶丝单纤强度和复丝强度均大于高模低缩型(HMLS)和高强低缩型(LS)涤纶丝,断裂伸长最小,模量居中;高模低收缩型、高强低收缩型涤纶丝沸水收缩率和干热收缩率均低于高强型涤纶丝;高模低收缩型、高强低收缩型涤纶丝的熔融温度没有明显差异;高模低收缩型涤纶的性能兼顾了高强和高强低收缩丝的优点。     

后加工中热处理张力变化对高模低收缩涤纶工业丝结构与性能影响

针对后加工热处理过程中高模低收缩型(HMLS)涤纶工业丝受热引起性能变化的问题,分别将HMLS涤纶工业丝置于150 ℃不同预加张力(0~0.10 cN/dtex)条件下热处理5 min,分析热处理前后样品的构象变化,阐明其性能调控的结构因素。结果表明:随着预加张力的减小,HMLS涤纶工业丝的断裂强度略有减小,初始模量和5%形变下的断裂强度明显降低,而断裂伸长率明显增大;热处理主要影响非晶区的结构变化,导致HMLS涤纶工业丝的非晶区取向变低、反式构象含量变小、片晶长周期变小以及非晶区厚度变小;可通过施加一定的预加张力有效抵消HMLS涤纶工业丝在后加工中受热时的收缩应力,从而降低非晶区分子链的运动能力,使得力学性能及非晶区结构变化幅度减小。     

HMLS高黏合轮胎增强骨架材料生产工艺的优化

以具有高模量、高取向度、高温下尺寸稳定、抗冲击好的HMIS涤纶丝为原料,对其采用直捻法加捻喷气织机织造,并选用环保的嵌段异氰酸酯配制浸胶液浸胶,优化浸胶工艺参数,生产出的高黏合轮胎增强骨架材料的断裂强力为214.8 N,定负荷伸长率4.7%,干热收缩率1.1%,附胶量3.2%,各项指标均优于老工艺,满足了汽车子午线轮胎...     

The Effect of Yarn Twist and Fibre Percentage in Blends on the Dimensional Properties of the Interlock Structure

An account is given of an investigation of the dimensional properties of a series of interlock weft knitted fabrics produced from open-end cotton-polyester blended yarns with different yarn twist, loop length, fibre percentage in blend, and variety of relaxation treatments. A comprehensive experimental analysis shows that the Ks value (stitch density multiplied by the square of loop length) is related to yarn density, fibre percentage in blends, and relaxation treatments. It is also concluded that the correct relaxation state for cotton fabrics to reach the maximum shrinkage is full mechanical relaxation, and for cotton polyester blended and 100% polyester fabrics is chemical relaxation treatment. The empirical results show that the effect of mechanical relaxation decreases as the percentage of polyester in blends increases.     

短纤纱动态拉伸性能

短纤纱的拉伸强力通常是评定纱线质量的重要指标。纱线拉伸强力在纺纱后道的大部分工序中(如整经、机织和针织)起着重要作用,因此对其精确的评定方法在工业生产中很重要。通过分析动态拉伸性能的定义和所用到的拉伸仪器,以环锭纺、转杯纺、喷气纺和摩擦纺的短纤纱的动态拉伸性能测试为例,做了几项有关理论和实验的工作,探讨了研究短纤纱动态拉伸性能在工业生产中的重要性,同时也总结出影响动态拉伸性能的因素有材料、纺纱参数和测试方法等,得出短纤纱静态和动态强力的关系。     

Investigation of antibacterial and antifungal properties of tufting carpets containing metal composite yarns

In this research, antimicrobial (antibacterial and antifungal) properties of tufting carpets containing metal/texturized polyester composite yarns were investigated. Carpet contains different yarn groups such as pile yarns, ground warps and wefts. Backing fabric’s warp and weft yarns are suitable for gaining antimicrobial activity because of their placement and low usage amount. Thus, textured polyester yarns were commingled with copper, stainless steel metal wires and silver metalized polyamide yarn. Backing fabrics were produced with four different placements by composite yarns. Antibacterial activity tests were applied to carpet samples according to AATCC 100 standard against K. pneumoniae and S. aureus bacteria. AATCC 30 – Part 3 standard was used for determining antifungal activity against A. niger. Results show that the antibacterial activity increases with increasing in the amount of metal composite yarn in unit area. Carpet samples which include copper or metalized silver composite yarn in all warps showed antibacterial activity about 99%. Moreover, antifungal activity can be provided against A. niger when copper and metalized silver composite yarn is used in all warps of carpet samples.     

PET／PA混纺喷气变形纱的物理性能

为了研究不同混纺比对纱线物理性能的影响,用聚酯（PET）和聚酰胺（PA）复丝制成了混纺喷气变形纱,并测定纱线的性能,如丝圈频率、不稳定性、外形膨松度、沸水收缩率、抗张强度及断裂伸长率。结果发现,与PET含量较高的混纺纱相比,PA含量较高的混纺纱其丝圈不稳定性较低,外形膨松度较小,但伸长率和绞纱收缩率较大。     

The dimensional and mechanical properties of wool/polyester fabrics made from vortex and ring-spun yarns

Fabric woven from wool/polyester (PES) Murata vortex spun (MVS) blend yarn is a commercially viable proposition particularly on the basis of advantageous wear-resistant properties, compared with fabric made from traditional worsted ring-spun yarn. However, in some early industrial trials with fabric made from 45/55-blend wool/PES MVS yarn, significantly greater relaxation shrinkage was found relative to comparable worsted ring-spun fabric. It was noted at the time that the amount of relaxation shrinkage in MVS fabric could be reduced to a large extent by using steamed MVS yarn.

In this study, the extent of variations in the dimensional and mechanical properties of fabric samples woven from a combination of steamed and unsteamed MVS yarn and equivalent worsted ring-spun yarn is examined. In general, greater hygral expansion and relaxation shrinkage were found in loom-state fabrics made from unsteamed MVS yarns, whereas the fabric made from steamed MVS and ring-spun yarns gave relatively low levels of relaxation shrinkage and hygral expansion. Permanent setting of fabrics, by pressure steaming, was found to be more effective than yarn pre-steaming in reducing relaxation shrinkage levels of fabrics made from unsteamed MVS yarn. After pressure steaming, all fabrics showed similar levels of relaxation shrinkage and hygral expansion.

Permanent setting of the fabrics, by pressure steaming, resulted in similar levels of relaxation shrinkage and hygral expansion, irrespective of the yarn production method; relaxation shrinkage fell to around 1% and hygral expansion increased by about 1%, relative to the loom-state samples. MVS fabrics were relatively heavier and fuller and had a firmer handle than the worsted ring-spun fabrics, reflecting the greater fabric weight, thickness and shear rigidity measured on these fabrics. These attributes are associated with different structures of the worsted ring-spun and MVS yarns used to make the fabrics.     

Effects of graft modification on apparent viscosity,adhesion, and film properties of sesbania gum for warp sizing

Abstract

In order to solve such utilization problems as excessively high apparent viscosity of sizing paste and poor adhesion to polyester fibers, caused by macromolecular inherent defects of native sesbania gum (SG), various amounts of methyl acrylate (MA) monomers were grafted onto molecular chains of native SG through initiation of Fenton's reagent and a series of SG-g-PMA with different grafting ratios were prepared. Effects of the graft modification on sizing properties of SG-g-PMA were studied in terms of apparent viscosity, contact angle of sizing paste on polyester fibers, water-solubility, mechanical properties of sizing film, adhesion to polyester fibers, and tensile properties of sized polyester warp yarns. It was found that the graft modification for SG was a simple and effective method to improve its sizing properties for polyester yarns and to omit specific viscosity reduction procedure used commonly for SG at present. In view of overall performance of SG-g-PMA sizes, the appropriate grafting ratio should be 18.70%.     

Effects of fiber types and blend ratios on Murata Vortex yarn properties

Murata Vortex spinning (MVS) system is one of the unconventional systems for yarn manufacturing. It is suitable for spinning of 100% cotton fibers, synthetic fibers, and cotton/synthetic fiber blends which are 1 inch or more in length. The production ranges are between Ne 15-60. Vortex yarn and fabrics have low hairiness, clear appearance, high resistance to pilling and abrasion. In this study, the vortex yarns with Ne 30 are produced in different blend ratios in Murata Vortex Spinner using carded cotton, viscose, modal, silver-added polyester (Flexsil-D2?), polyester, and nylon 6.6 fibers. Vortex spun yarns are tested to determine the yarn properties which are diameter, density, roundness (shape), unevenness, imperfection, Uster hairiness (H), Zweigle hairiness, tenacity, and elongation. The study reveals that the fiber type has quite significant effects on yarn properties. In terms of structural properties, cotton is the most negative fiber while regenerated cellulosic fibers are the most positive. As modal, nylon and polyester fiber increase yarn strength, nylon and viscose fiber increase breaking elongation. Viscose and modal reduce unevenness, imperfection and hairiness while polyester and nylon exhibit more negative effect on these properties.     

Study on thickness loss of cut-pile carpet produced with heat process modified polyester pile yarn. Part II: dynamic loading

Thickness loss (TL) is one of the most important mechanical properties in each carpet. In this research, four types of ATY polyester pile yarns were used to prepare the cut-pile carpet samples. They were normal ATY polyester filament pile yarns and three yarns that modified by heat processes including friezing, heat setting, and twist heat setting. Woven carpet samples are subjected to standard dynamic loading test. Results show that friezing and heat setting processes have no significant effects on carpet dynamic recovery or TL after dynamic loading. Also, decreasing temperature of twist heat setting, the polyester pile yarns could not modify carpet TL after dynamic loading.     

ON THE tanδ-FREQUENCY RELATIONSHIP OF FOODS AND AGRICULTURAL COMMODITIES1

Published discrete relaxation times spectra of agar and alginate gels, alfalfa, apple and potato flesh, meat, cheese and wheat dough were used to calculate the frequency or frequencies where the phase angle δ(ω vs frequency, ω, relationship peaks. This was done by solving, numerically, the equation dtanδ(ω)/dω= O where d²tanδ(ω)/dω < O, with tanδ(ω) being an algebraic expression derived from the discrete Maxwell model of stress relaxation. The ω_peak of the materials examined was in the range of 10^?3 to 10^?1 Hz band, setting a lower limit to the frequencies at which such materials can be compared by dynamic tests. This also indicates that the plot of tanδ(ω) vs ω in linear or logarithmic coordinates must have a negative slope at any frequency range above about 0.5 Hz. The frequency at which the peak appears, ω_peak, is primarily determined by the relative weight of the elastic component and the elements of long relaxation times. The higher it is the lower ω^peak is. Thus, the latter can serve as a measure of solidity, inherent to the material or caused by external conditions or through a textural modijication.     

Development and characterization of conductive ring spun hybrid yarns

Development of conductive yarns for smart textile applications is the most demanding area of research these days. This study was aimed to investigate the effect of yarn constructional parameters, and relative humidity on electromechanical properties of conductive ring spun hybrid yarns. Stainless steel (SS) fibre was blended with polyester and viscose fibre separately on 12% and 24% weight basis to produce hybrid conductive yarns at three different levels of twist factor. The electromechanical properties of yarns were evaluated in response to change in blend type, blend ratio, twist factor, and relative humidity. The content of SS fibre is found to be more effective followed by the twist factor and blend type to govern the linear electrical resistance (LER) of conductive yarns. In addition, on increasing relative humidity, the LER of viscose stainless steel (VS) hybrid yarns are found to drop significantly than that of polyester stainless steel (PS) hybrid yarns.     

羊毛/双抗涤纶纤维混纺纱生产实践

针对羊毛与涤纶纤维混纺织物易起毛起球和起静电问题,选择强力相对较低且具有良好抗静电性的羊毛与双抗涤纶进行混纺,通过优化改进羊毛与双抗涤纶纤维条染复精梳的染色工艺、复洗工艺及混纺工艺,实现了双抗涤纶纤维和羊毛条染色均匀,降低了双抗涤纶纤维染色残留低聚物,改善了羊毛/双抗涤纶纤维混纺过程中的飞毛绕毛现象,既解决了羊毛/涤纶纤维混纺织物的起毛起球和起静电现象,又不会因纤维强力过低而影响纺纱和织造生产,拓展了双抗涤纶在精纺毛织物产品开发中的应用。     

Studies on cotton–acrylic bulked yarns produced from different spinning technologies. Part I: yarn characteristics

The effects of different factors, namely spinning technologies (ring, rotor and DREF-II, i.e. Group A yarns), position of shrinkable acrylic feed sliver in DREF-II friction spinning system (Group B yarns) and proportion of shrinkable acrylic core fibre in core-sheath type DREF-III friction spun yarns (Group C yarns) on various properties of cotton-acrylic–blended bulked yarns have been studied. The bulk in the yarns was developed by relaxing shrinkable acrylic component of the yarns using boiling water treatment. All the above factors have a significant impact on various properties of cotton–acrylic blended bulked yarns. For all the yarns, after boiling treatment, there is lengthwise shrinkage of yarns and the specific volume also increases. Tenacity and breaking elongation of all the yarns of Group A and Group B increase after hot water treatment, whereas in case of core-sheath type DREF-III yarns (Group C yarns) there is drop in tenacity and breaking elongation after similar treatment. In general, for all the yarns the flexural rigidity of the yarns reduces and compressibility and compressional recovery of increases after bulking treatment.     

Some properties of potatoes and their starches II. Morphological,thermal and rheological properties of starches

The physico-chemical, morphological, thermal and rheological properties of the starches separated from different potato cultivars (Kufri Jyoti, Kufri Badshah and Pukhraj) were studied. The starches separated from the mealier cultivars (Kufri Jyoti and Kufri Badshah) showed lower transition temperatures (T_o; T_p and T_c), peak height indices (PHI), and higher gelatinization temperature range (R) and enthalpies of gelatinization (ΔH_gel) than the starch from the least mealy cultivar (Pukhraj). Swelling power, solubility, amylose content and transmittance values were observed to be higher for Kufri Jyoti and Kufri Badshah potato starches, while turbidity values were lower for these starches. The rheological properties of starches, measured using a dynamic rheometer, showed significant variation in the peak G′, G″ and peak tan δ values. Kufri Badshah and Kufri Jyoti starches showed higher peak G′, G″ and lower peak tan δ values than Pukhraj starch during heating and cooling cycles. Kufri Jyoti and Kufri Badshah starches showed higher breakdown in G′ than starch from the Pukhraj potato cultivar. The large-sized granules of the starches from Kufri Badshah and Kufri Jyoti appeared to be associated with higher values of peak G′ and G″ and consistency coefficient. Starch from the least mealy cultivar (Pukhraj) showed higher retrogradation, which increased progressively during storage at 4 °C for 120 h.     

热处理对摩擦纺包芯纱性能的影响

主要讨论了Dref-3型摩擦纺包芯纱包覆层组分的比例（包覆率）以及在干、湿自然状态下热处理对纱线热收缩性、包覆层抗滑脱性及拉伸性能的影响。芯纱采用聚酯长丝,包覆层为棉纤维。实验表明热处理能够明显提高纱线的热收缩性与包覆层抗滑脱性能,而且在湿状态下包芯纱的抗滑脱性能较干状态更好。纱线断裂伸长随着处理温度的增加而增加。包覆率提高,纱线热收缩性降低,抗滑脱性提高,断裂强力增加。     

Effects of Heating,Vacuum Drying and Steeping on Gelatinization Properties and Dynamic Viscoelasticity of Various Starches

Starches having A‐ and B‐type X‐ray diffraction patterns (A‐ and B‐type starches) were modified by heating at 120 °C for 2 h (HT), vacuum drying at room temperature for 20 h (VD) and steeping at 50 °C for 20 h (ST). The properties of starches were compared using differential scanning calorimetry (DSC) and dynamic viscoelasticity behavior during heat processing (G' behavior). As observed by DSC, HT rarely changed the gelatinization properties for A‐type starches, but decreased the gelatinization temperatures and enthalpies (ΔH) for B‐type starches. A shift of the X‐ray diffractograms from B‐type to A‐type patterns was not detected after HT. Similar changes in gelatinization properties were observed for B‐type starches after VD. ST increased the gelatinization temperatures and also narrowed the gelatinization temperature range irrespective of crystal type. Both HT and VD decreased the peak temperature (T_p) in G' behavior and increased the peak G' value for B‐type starches. ST increased T_p and also decreased the peak G' value irrespective of starch crystal type. G' values after reaching T_p — which indicate the viscoelasticity of the swollen starch granules without breakdown — showed significant increases only for B‐type starches after HT.