Properties of cotton yarns after slack swelling and stretching in presence or absence of alkali. II

An investigation on the properties of solution‐stretched ring spun and rotor spun cotton yarns at regular time intervals was made. Significant changes in the properties of these yarns are observed. The changes in fine structure are evaluated by means of infra red spectroscopy and X‐ray diffraction methods. Ring spun cotton yarns exhibit better abrasion resistance than do rotor spun yarns. Abrasion resistance of NS‐ring and rotor spun yarns is higher than their counter parts. WS‐ring spun yarns are characterized by higher compression values, explaining the softness produced by the stretching treatment. The dyeability of the treated yarns is also studied with reactive dye, and the color values are found to be significantly greater for WS‐ring and rotor spun yarns. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

A study of the response of open end and ring spun yarns to zinc chloride and sodium hydroxide

An investigation of the swelling behavior of open end and ring spun yarns in slack condition in 64.5% (w/w) aqueous zinc chloride and sodium hydroxide 22% (w/w) for different intervals ranging from 30 to 90 min is reported. The results show that the response of the yarns to the swelling agents is different in that the products treated with zinc chloride are found to possess higher strength and higher bending rigidities but low elongation. Swelling of yarns with sodium hydroxide has resulted in large increase in elongation. The other properties, namely, coefficient of friction and abrasion resistance, are found to be slightly higher than that of the yarns treated with sodium hydroxide. Degree of set of open end yarns is significantly higher than that of the ring spun yarns. Coefficient of friction and abrasion resistance of the zinc chloride treated yarn samples are found to be slightly higher than that of the sodium hydroxide treated samples.     

Experimental study of the frictional properties of friction spun yarns

This article reports the results from a study conducted to characterize the frictional properties of friction spun yarns. The aim of the study was to obtain data on the surface mechanical properties of a variety of friction spun yarns. The study was essential as the surface mechanical properties influence the fabric formation, bonding strength, and high‐performance properties of yarns. The yarns used in the study were made from different fibers and were spun at different speeds. The capstan method was used to obtain the friction force values between the yarns and a glass cylindrical rod. The experiment was conducted at different tensions. The results indicate that the friction of friction spun yarns are influenced by different factors such as the type of fiber and tensions applied. The results obtained help to understand the surface mechanical properties of high‐performance yarns and their influence on the performance characteristics of friction spun yarns. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2450–2454, 2003     

摩擦纺包缠纱纺织预型件及其复合材料的加工

本文研究了摩擦纺包缠纱纺织预型件及其复合材料的加工性能。借助地机织，纺织和针织等三种预型件加工方法，通过必种典型纺织结构的加工研究了摩擦纺包缠纱的预型件加工性能，并在平板热压机上成型了几种结构的复合材料，结果表明：摩擦纺包弹纱可以用于纺织预型件加工以成型纺织结构型的复合材料，灵活地运用纺织结构可以得到独特结构的复合材料，此外摩擦纺包缠纱经适当防剥离处理后，可加工出紧密结构机织物，以成型较高纤维体积     

Comparative study of colour yield of cotton knitted fabric made by torque‐free ring‐spun yarns

Torque‐free ring spinning is a new spinning technology that has produced yarns with low twist and balanced torque. In this study, a commercially torque‐free ring‐spun yarn, namely Estex yarn, with three types of cotton fibre, i.e. Pima, upland and organic cotton, were used. Cotton fabric samples were knitted with Estex yarns and conventional ring‐spun yarns. The fabric samples were then dyed with two reactive dyes, Remazol Black B and Remazol Brilliant Blue R Spec., and the fabric dyeability was measured in terms of reflectance and colour yield. Finally, the results were analysed using the statistical software package SPSS and the results revealed that fabric samples manufactured by Estex yarns could achieve a better colour yield than conventional ring‐spun fabric samples. In addition, the Pima cotton gave the best colour yield, followed by upland cotton and organic cotton.     

热塑性树脂基复合材料用摩擦纺混纤纱

对连续纤维增强热塑性树脂基复合材料，增强纤维和热塑性树脂的结合是这类复合材料加工的难点。从９０年代起，Ｗｕｌｆｈｏｒｓｔ等探索性地研究了用摩擦纺方法将增强纤维和树脂纤维一起加工成热塑性复合材料用混纤纱。本文对这种摩擦纺混纤纱加工方法进行一步讨论，纺制了进一步讨论，纺制了几种混纤纱并通过扫描电镜和纱线均匀度测试仪研究了其结构。     

喷气纺包芯纱的研制

喷气纺纱是利用喷嘴内部产生的高速旋转气流对纤维须条进行假捻包缠的一种纺纱方法。通过对不同长丝为纱芯纺制喷气包芯纱,研究不同原料包芯纱的结构特点,并与环锭纺包芯纱作了比较,验证了喷气纺包芯纱比环锭纺包芯纱的包覆效果好。     

K‐M theory of fabric knitted by three‐channel rotor spun wool yarn

Two‐component and three‐component color blended yarns were spun by red, yellow, and blue wool slivers using a three‐channel rotor spun machine, and the corresponding plain fabrics were knitted. The color‐matching models of K‐M theory were built with the relative method and the least squares method, respectively. Colors and blending ratios of the fabrics were predicted by the model. The results showed that the average color differences of the samples predicted by the two methods are both about 1.0 and the mean value of the proportional error is below 3%. The least squares method has a better color‐matching effect for the three‐component sample, and the relative value method has better color‐matching results for the two‐component sample. When the tolerance range is 2.0, the pass rates of the samples predicted by either the relative value method or the least squares method reach 100%.     

Tensile behavior of polyester yarns modified by trichloroacetic acid–methylene chloride treatment

The effect of trichloroacetic acid-methylene chloride (TCAMC) solvent system on the mechanical properties of poly(ethylene terephthalate)-based flat, high twist, and spun yarns were studied. Pretreatments were carried out in an unrestrained state at different concentrations for various times and without employing any heat treatment. The stress-strain behavior of yarns was analyzed. The stress-strain curves showed that the treated yarns exhibit different morphologies. A significant plastic flow region could be detected in treated yarns. The higher interaction between the reagent and the polyester revealed the closeness of their solubility parameter values. Structural modification of yarns due to TCAMC treatment led to an increase in elongation without significant reduction in strength. The reagent caused reduction in initial modulus, yield stress, and an increase in work of rupture. The increase in work of rupture was higher in flat yarn but not appreciable in the other two yarns. Statistical analysis of the test data was done. © 1996 John Wiley & Sons, Inc.     

Fabrication and mechanical properties of carbon nanotube yarns spun from ultra-long multi-walled carbon nanotube arrays

Carbon nanotube (CNT) yarns have been fabricated by dry spinning from vertically aligned millimeter-long multi-walled carbon nanotube (MWCNT) arrays and their mechanical properties have been studied. By using 2-mm long CNTs and densely packing of CNT yarns we achieved a tensile strength of 1068 MPa and Young’s modulus of 55 GPa. Our CNT yarns have diameters of tens of micrometers being easy to handle and possessing high effective load capacity up to 0.81 N. We discuss mechanical properties of CNT yarns spun from relatively thick MWCNT along with a detailed analysis of various post-spin processes and their effect on CNT yarns characteristics. Also, we point out the difference between mechanical properties of dry spun CNT yarns and conventional spun textile yarns.     

The influence of yarn-processing parameters on the tensile properties and structure of poly(l-lactic acid) fibres

This paper examines the influence of processing parameters on the physical properties and structure of yarns constructed from poly(l-lactic acid) (PLLA) fibres. Commercially produced spun- and false-twist texturised (FTT) PLLA yarns, and knitted fabrics derived there from were characterised in terms of their tensile properties, and structurally using differential scanning calorimetry (DSC) and wide angle X-ray diffraction. The effects of pre-dye heat-setting at 130 °C for varying times was assessed in terms of the resultant tensile properties of the yarns. The as-received FTT yarns (and hence their derived fabrics) differed in properties and fibre microstructure as compared to the spun yarns (and fabrics). More significantly, for both FTT and spun materials, differences in fibre properties and structure were observed between yarns removed from the fabrics and their respective feed-yarns. We associate this with possible thermomechanical influences experienced by the fibres during the knitting process. The duration of heat-setting influenced the tensile properties and DSC spectra for both types of yarn. Scouring following heat-setting was also carried out, and this produced no measurable additional effect on the spun yarns, but FTT yarns heat-set for less than ca 45 s showed instability to scouring.     

Structure development of poly(L‐lactic acid) fibers processed at various spinning conditions

Poly(L ‐lactic acid) (PLA) filaments were spun by melt‐spinning at 500 and 1850 mm^?1, and further drawn and heat‐set to modify the morphology of these PLA filaments. PLA yarns were characterized by wide‐angle X‐ray diffraction (WAXD) and sonic method. WAXD reveals that PLA yarns spun at 500 mm^?1 are almost amorphous while the PLA filaments spun at 1850 mm^?1 have about 6% crystallinity. This is different from PET filaments spun at the same speed that have almost no crystallinity. Both drawn‐ and heat‐set PLA filaments showed much higher crystallinity (60%) than do as‐spun fibers produced at 500 and 1850 mm^?1 speed, which is also higher than the usual heat‐set PET yarns. It appears that crystalline orientation rapidly reaches a value in the order of 0.95 at 1850 mm^?1 and that drawn‐ and heat‐set yarns have almost the same crystalline orientation values. Molecular orientation is relatively low for as‐spun PLA yarn, and molecular orientation increased to ～0.5 after drawing or heat–setting or both. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1210–1216, 2006     

Effect of Air-Jet Texturing on Adhesion Behaviour of Technical Polyester Yarns to Rubber

Air-jet texturing of technical polyester yarns was performed in order to improve its adhesion to rubber. The air-jet texturing parameters were selected with great care to minimize the mechanical loss. H-adhesion tests were used to characterize the adhesion of the yarns to rubber. A significant increase in the adhesion of dimensionally stable polyethylene terephthalate yarn, textured with an overfeed level of 15% (DSPET15), was recorded, while a decrease in the adhesion of high tenacity polyethylene terephthalate (HTPET) yarn was observed for all overfeed levels. The effects of air-jet texturing on the adhesion of technical polyester yarns were discussed in terms of changes in the yarn geometry and changes on the single fiber surfaces. Changes in the yarn geometry were investigated by optical microscopy studies, while changes on the fiber surface were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and environmental scanning electron microscopy (ESEM) studies. It was observed that air-jet texturing alters both the yarn geometry and the single fiber surfaces, leading to a change in the adhesion to rubber.     

Effect of orientation and crystallinity on the photodegradation of poly(ethylene terephthalate) fibers

In this research, photodegradation of poly(ethylene terephthalate) (PET) fibers was investigated with emphasis on the morphological state of yarns. Two kinds of yarns, FDY (Fully Drawn Yarn) and POY (Partially Oriented Yarn), with different molecular orientation and crystallinity were applied in this research. FDY is spun in the same way as POY and subsequently drawn at high speed and then entangled before winding up. This sample has higher molecular orientation and crystallinity than the POY sample. Several analytical methods were applied in this study: viscometry, X‐ray diffraction, FTIR spectroscopy, UV–Visible spectrophotometry, and mechanical testing. Viscometry was used to determine molecular weight as a monitoring factor for degradation. X‐ray diagrams showed higher crystallinity for FDY samples during weathering process by irradiation. Results of mechanical testing indicated that the tenacity of the FDY fibers had less deterioration in comparison with the POY ones. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Properties of yarns spun from a cellulose triacetate melt

Conclusions The physicochemical and physicomechanical properties of yarns spun from a cellulose triacetate melt have been studied.It has been shown that in physicomechanical properties CTA yarns spun from the melt are identical to yarns spun by the dry method.It has been found that the lower sorptive power and lower shrinkage of yarns from the melt are connected with the special features of their spinning.Translated from Khimicheskie Volokna, No. 5, pp. 23–25, September–October, 1984.     

Mechanical Behavior of Poly(Ethylene 2,6-Naphthalene-Dicarboxylate) (PEN) Fibres near the Glass-Rubber Transition Temperature

Abstract

The mechanical properties of as-spun poly(ethylene 2,6-naphthalene-dicarboxylate) (PEN) fibres were studied in order to characterize this relatively new material near its glass-rubber transition.

Tensile tests were carried out on amorphous (low-speed spun) PEN filaments. The temperature range of 90°C up to 160°C was covered using increments of 10°C. A transition from necking and cold drawing to rubber-like behavior was observed in the stress-strain relationship. Dynamic mechanical experiments were carried out on PEN yarns spun at speeds from 500 to 4000 m min^?1. Both temperature and frequency were varied. The maxima in loss modulus depend on spinning speed. Tensile behavior and dynamic mechanical behavior of PEN fibres demonstrate that the glass-rubber transition temperature of PEN is approximately 125°C.     

Electrospun self‐assembled nanofiber yarns

A technique for making self‐assembled electrospun (E‐spun) nanofiber yarns from poly(acrylonitrile) in a single step is described. The process involved formation of the nanofiber yarn directly within the electrospinning zone and its removal before it can reach the counter‐electrode. The yarn is presumably formed due to splitting of the main jet into numerous nanojets and their reassembly into a single entity midway between the two electrodes. The process was found to occur at a particular field strength, which varied considerably with the concentration of the polymer dope. The gross morphology of yarns and the alignment of nanofibers in the yarn were evaluated by scanning electron microscopy (SEM). The rationale behind the formation of the yarn like structure has been explained. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Studies on dyeing and structural behavior of chemically treated polyester yarns

The dyeing behavior of poly(ethylene terephthalate) based flat, high twist, and spun yarns pretreated with trichloroacetic acid–methylene chloride (TCAMC) reagent was studied. Disperse dyes having two different energy levels were employed for the dyeing work. The effect of time, temperature, and dye diffusion transition temperature (T_D) on dye uptake was analyzed. A considerable increase in equilibrium dye uptake and decrease in T_D of all the treated yarns were observed. The variation in dye diffusion behavior of higher and lower molecular weight dyes and the difficulties encountered in calculating the diffusion coefficient of the dyes are discussed. The structural and morphological changes effected by the pretreatment were also investigated using XRD and SEM, respectively. The increase in lateral order of the treated yarns was noted. The possible reason for an unusual relationship between the increase in lateral order and increase in dye uptake was explained. The cross-sectional shape and swelling and the smoothening out of the fiber surface were evidence by SEM. © 1996 John Wiley & Sons, Inc.     

The effect of hot-wet draw ratio on the coefficient of friction of wet-spun acrylic yarns

A series of wet-spun poly(acrylonitrile-co-vinyl acetate) yarns that were hot-wet stretched to a draw ratio range of 2.0 × ?7.0 × were made for study of surface morphology and frictional characteristics. These yarns show an increase in draw ratio. The fiber to fiber coefficient of friction, measured parallel (line contact), and perpendicular (point contact), increases with draw ratio, giving an excellent correlation between orientation and friction. The effects of hot-wet draw ratio on the surface structure and its frictional behavior are discussed.     

Designing polylactide/clay nanocomposites for textile applications: Effect of processing conditions,spinning, and characterization

An experimental study was carried out to design polylactide (PLA)-clay nanocomposites for developing fibers. PLA and 1–10 wt % of a selected organomodified bentonite (Bentone® 104-B104) were melt mixed to examine the effect of processing conditions (temperature, shear, residence time) on the morphology of performed polymer nanocomposites (PNC). Because of a good compatibility with PLA matrix, the dispersion of B104 occurred under different conditions without difficulty, and a similar morphology was obtained. The results obtained showed that at low temperature of mixing, the shear stress exerted on polymer has a key role on the extent of intercalation and delamination. Upscale experiments were further performed using optimized conditions and 4 wt % B104 was added to PLA matrix by melt blending to produce PNC for spinning. Then, the recovered PNC were melt spun to produce multifilaments yarns, and it was demonstrated that surprisingly, it is not necessary to use a plasticizer to spin a blend with 4 wt % B104. The properties of the yarns have been studied in terms of clay dispersion as well as thermal, mechanical, and shrinkage properties. B104 could be added up to 4 wt % into PLA without detrimentally sacrificing the tensile strength of melt-spun filaments, especially at high draw ratio. Interestingly, the PNC-based multifilaments were knitted and the flammability studied using cone calorimeter at 35 kW/m². A strong decrease, up to 46%, of the heat release rate was measured. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008