The Influence of Elimination of Roving Frame on Ring Spun Cotton Yarn Characteristics

Generally, ring spun yarns are manufactured from roving which is produced by roving frame. In this paper, an experiment has been done producing ring spun cotton yarn directly from finisher drawn sliver eliminating the roving frame. Total 3 types of yarn with the various linear density of 8 Ne, 10 Ne & 12 Ne were produced using a roving frame and without using a roving frame. In the next step, physical and mechanical properties of those yarns including unevenness, imperfections, hairiness & tenacity were investigated. The result showed that ring spun cotton yarns produced from sliver exhibited inferior physical and mechanical properties compared with samples from the conventional ring spinning system.

Abrasion Resistance Comparison between Rotor and Ring Spun Yarn

On the base of literature review and the analysis of yarn properties, yarn structure and some other facts, the abrasion resistance of both rotor spun yarn and ring spun yarns are discussed. The results show that with the same raw material and twist, the rotor spun yarn has lower abrasion resistance than that of ring spun yarn, because of the higher twist employed, the abrasion resistance of rotor spun yarn is higher than that of ring spun yarn.

基于sirofil-spun新型花式纱的纺制及性能分析

基于sirofil-spun新型花式纱的纺纱方法,阐述了新型sirofil-spun的纺纱原理即对sirofil-spun和嵌入式纺纱的结合原理,在QFA1528细纱机上进行改装,开创出sirofil-spun新技术,纺制出新型的花式纱。在保证纺纱工艺参数及纱线中长丝和短纤维含量相同的情况下,分别纺制150 dtex/66.7dtex/66.7 dtex新型sirofil-spun花式纱与普通sirofil-spun花式纱,并对其强伸性能、条干、毛羽指标进行了测试和对比分析,同时利用MDA1300视频显微镜和YG172型纤维切片器进行观察并进行纱线纵、横向结构分析。研究结果表明:纱线的纵、横截面中,三种花色呈螺旋型外观,表面光洁,结构稳定;对于相同线密度的花式纱,新型sirofil-spun花式纱的断裂强度和断裂伸长率高于普通sirofil-spun花式纱,条干和毛羽水平也优于普通sirofil-spun花式纱。

三种不同工艺条件对新型sirofil-spun三色花式纱外观与成纱质量的影响

探讨三种不同工艺条件对新型sirofil-spun三色花式纱外观与成纱质量的影响。采用新型sirofil-spun纺纱方法即对sirofil-spun和嵌入式纺纱原理的结合,并且在三种不同工艺条件下,通过改变粗纱与长丝的相对位置,即粗纱靠左侧长丝、粗纱在两根长丝之间和粗纱靠右侧长丝,形成不同的成纱方式纺制出新型的三色花式纱;利用i-speed高速摄影机和MDA1300视频显微镜对所纺出花式纱的外观进行观察与分析,并且对三种花式纱线的强伸性能、条干、毛羽进行对比分析。研究结果表明:三种不同工艺条件下会形成不同的成纱加捻机理,纺成花式纱的三种色彩产生不同的排列;粗纱靠近左侧长丝喂入的成纱方式所纺三色花式纱的成纱质量较好。

Structure and magnetocaloric effect in melt-spun La(Fe,Si)_(13) and MnFePGe compounds

The magnetocaloric properties of melt-spun La(Fe,Si)13 and MnFePGe compounds were investigated. Very large value of magnetic entropy change ｜ΔS｜=31 and 35.4 J·(kg·K)-1 under 5 T were obtained at 201 K in LaFe11.8Si1.2 melt-spun ribbons and at around 317 K in Mn1.1Fe0.9P0.76Ge0.24 melt-spun ribbons, respectively. The large magnetocaloric effect results from a more homogenous element distribution related to the very high cooling rate during melt-spinning. The excellent MCE properties, the low materials cost and the accelerated aging regime make the melt-spun-type La(Fe,Si)13 and MnFePGe materials an excellent candidate for magnetic refrigerant applications.

Crystallization behaviour and high coercivity of (Nd,Pr)_(13)Fe_(80)Nb_1B_6 melt-spun ribbons

Amorphous （Nd,Pr）13Fe80Nb1B6 ribbons were crystallized at 670-730°C for 5-25 min to study the effects of isothermal crystallization on their behavior and magnetic properties. XRD results indicate that the isothermal incubation time is 12, 5, and less than 5 min at 670, 700, and 730°C, respectively. High coercivities, with the maximum value of iHc = 1616 kA/m at 700°C for 19 min, measured by a physical property measurement system, are obtained in the crystallized ribbons. This is mainly attributed to the addition of Pr and Nb, because Pr2Fe14B has a higher anisotropic field than Nd2Fe14B, and Nb enriched in the grain boundary regions can not only reduce the exchange-coupling effects among hard grains, but also impede grain growth during the crystallization process. In addition, it should also be related to the characteristics of the furnace that the authors designed.

Magnetoresistance and exchange bias in high Mn content melt-spun Mn_(46)Ni_(42)Sn_(11)Sb_1 alloy ribbon

Highly textured Heusler alloy Mn_（46）Ni_（42）Sn_（11）Sb_1 ribbons were prepared by melt spinning. The annealed high Mn content Mn46Ni42Sn11Sb1 ribbon cross-section microstructure, crystal structure, martensitic transformation（MT）, and magnetoresistance（MR） properties were investigated. The MR in the annealed ribbon was assessed by the magnetic field direction perpendicular to the ribbon surface with the magnetic field up to 30 k Oe. The large negative value of 25% for MR was obtained at 244 K. The exchange bias（EB） effects of the as-spun and annealed ribbons were investigated. After annealing, the EB effects have been improved by about 25 Oe at the temperature of 50 K. The magnetizations have increased approximately by 10% more than the as-spun ribbon.

REPORT ON A PROJECT AIMED AT INCREASING THE STRENGTH OF FRICTION SPUN YARN BY USING A FALSE TWIST PROCESS

The lower strength of friction spun yarns has became a key problem that hinder the develop-ment of friction spinning,especially in high speeds and fine yarns.In this paper a project aimed atincreasing the strength of friction spun yarns by using a false twist process has been made.In re-ported experiment false twist was inserted into the yarn which has been formed on a friction spin-ning machine,so that it made the yarn untwist at first,then regain the twist.In the meantime draftwas applied to generate more tension than that which had been experienced during yarn formationon the friction spinning machine.It made the yarn reforming and the loosely bound fibres in thefriction spun yarn formed due to extremely low tension on the friction spinning machine becametighter.Results indicate that with the proper draft,tension and false twist the tenacity of processedyarn will increase more than 10%.This project is an attempt to discover whether improvements can be made and whether it isworth pursuing research into modifications of yarn structure.The results imply that if the yarntension can be raised during yarn formation on the friction spinning machine or a chance is offeredto the yarn to reform after the yarn formation the yarn tenacity will be increased obviously.

The Behavior of the Rotor Spun Yarn(OE yarn)with Involving Twist

The rotor spun yarn(OE yarn),twist of which is calledlayering twist,was added a few involving twist,and itsstructure and properties were measured.The experimen-tal results have shown that the morphological structure ofthe rotor spun yarn with modified twist was changed andits tensile properties and abrasion resistance were im-proved.

A Study of the Behaviour of Denim Cloth Made from Modified Rotor Spun Yarn

This paper described the physical behaviour of three types of denim cloths produced from rotor yarn, ring yarn and modified rotor yarn (prepared by adding conventional twist to rotor yarn) respectively. Experimental work showed that denim cloth produced from the modified rotor yarn has superior properties over conventional rotor yarn in terms of surface texture and appearance,tearing strength and resistance to abrasion.

Model to Study Resin Impregnation Process of Premix Made of Friction Spun Core Yarn

A model was deveIoped to investigate impregnation behavior of thermoplastic resin into filament bundle based on Darcy's law. Consolidation processes of unidirectional laminate were performed to evaluate the validity of the model. Friction spun core yarns were used in the experiments with polypropylene fiber sheath and glass filament core. The processing conditions, such as temperature and pressure, and filament parameters were taken into consideration. A good agreement was found between theoretical prediction and experiment data.

Fibrillation Properties of Solvent - spun Cellulose Fiber

In this paper, fibrillation properties of solvent - spun cellulose fiber and some influencing factors are analyzed based on the experiment results. It is pointed out that special textile styles and aesthetic appearance could be obtained by controlling the fibrillation.

THE EFFECTS OF ULTRA DRAWING ON THE CRYSTAL STRUCTURE OF GEL SPUN POLYETHYLENE FIBERS

It is believed that gel spun polyethylene(PE)fibers have a somewhat extended chain crystalstructure,because of the disentangling of the chains which takes place in semi-dilute solutionand the ultra high draw ratio used.Ten years ago,PE shish-kebabs grown from dilute solutionwere proved to have extended chain backbone which causes the raising of its melting point.These crystals were found to have a triclinic crystal phase,This study shows a different result forgel spun ultra high drawn PE fiber.The unit cell remains orthorhombic even if the draw ratioreaches 50;as the draw ratio increases,the length in a and b axes are shortened while that in c ax-is changes quite insignificantly.When the draw ratio is over 10,two endothermic melting peakscan be seen in the DSC curves with corresponding peak temperature of 136.7-145.3℃.The lat-ter peak is attributed to the amount of extended chain crystal.

EFFECTS OF NITRIDING TEMPERATURE ON MAGNETIC PROPERTIES OF MELT-SPUN Pr1.4Fe10.5Mo1.5Nx AND ITS PHASE ANALYSIS

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Effects of electrochemical oxidation on surface and mechanical properties of dry-jet wet spun carbon fibers

The surface of dry-jet wet spun carbon fibers(CFs)is relatively smooth compared with those of wet spun CFs,which results in weak interfacial interactions between the fiber and the polymer resin.A surface functionalization treatment is particularly important to unleash the full potential of the superior mechanical properties of dry-jet wet spun CFs.In this study,the effects of electrochemical oxidation treatment time and current density on the surface structures and the mechanical properties of dry-jet wet spun CFs were investigated.The interlaminar shear strength of the CFs improves significantly from 69 to 84 MPa after 120 s of treatment.Further structural analysis reveals that the improvements are due to the addition of oxygen-containing functional groups and the optimization of the morphology on the surface of the CFs.

Microwave Behavior of α-Fe/Fe_3B/Y_2O_3 Nanocomposites in GHz Range Prepared by Melt-Spun Technique

Nanocomposites α-Fe/Fe 3B/Y 2O 3 were prepared by a melt-spun technique, and the electromagnetic wave absorption properties were measured in the 0 05～20 05 GHz range. Compared with α-Fe/Y 2O 3 composites, the resonance frequency (f r) of α-Fe/Fe 3B/Y 2O 3 shifted to a higher frequency range due to the large anisotropy field (H A) of tetragonal Fe 3B (～0 4 mA·m -1). The relative permittivity (ε r=ε r′-jε r″) was constantly low over the 0 5～10 GHz region, which indicates that the composite powders have a high resistivity (ρ=～100 Ωm). The effective electromagnetic wave absorption (RL<-20 dB) was obtained in a frequency range of 2.7～6.5 GHz on resin composites of 80% (mass fraction) α-Fe/Fe 3B/Y 2O 3 powders, with thickness of 6～3 mm respectively. A minimum reflection loss of -33 dB was observed at 4.5 GHz with an absorber thickness of 4 mm.

Giant Magnetoimpedance Effect of As-Spun Nanocrystalline Ribbon of FeZrBCu Alloy

The melt-spun nanocrystalline ribbons of Fe86.5Zr7B4Cu2.5 alloy were prepared by single wheel technique with wheel surface velocity of 37 m/s.It is found that there appears a lot ofα-Fe nanoparticles with sizes of 5-10 nm in as-spun nanocystalline ribbons which exhibit giant magnetoimpedance(GMI)effect.The GMI ratio up to 33.69% at frequency f=1MHz under a DC field of 5 172A/m can be obtained.

Coagulating Processes of Impregnating Spun-Laced Non-Woven Substrates with PU Dispersion

PU dispersion was chosen as an impregnating agent to produce leather-like sheet on spun-laced nonwoven.Three typical coagulating processes were studied.It was found that the best coagulating process for the chosen PUdispersion to get the leather-like sheet was coagulation in a sodium chloride solution.The detailed study of coagu-lating processes in sodium chloride solution was carriedout and optimal condition was obtained.Some experi-mental results were elucidated.Keywords:PU dispersion,coagulating, impregnating,ar-tificial leather,spun-laced nonwoven.

THE CHARACTERISTIC STRUCTURE AND ITS FORMATION MECHANISM OF GEL-SPUN UHMW-PE FIBERS

Ultra-high strength and modulus polyethylene fibers can be produced from UHMW-PE(ul-tra-high molecular weight polyethylene) by gel spinning and ultra-high drawing method.The spe-cial supermolecular structure of″shish-kebabs″ is the intrinsic course for the fiber having highperformance.In this paper,the formation mechanism of the characteristic structure of PE fibershas been investigated by means of SEM,DSC,WAXD,SAXS and TEM,The experimental resultsshow that the extended-chain structure of PE fibers is formed originally from the bridged mole-cules in amorphous region and increased gradually during further drawing porcess.The″shish-kebab″ structure is formed by the combination of extended-chalnS and originalfolded-chains.

Effects of Stretching Ratio and Temperature on Phase Transition of Melt-spun Poly(Vinylidene Fluoride) Fibers

The effects of stretching ratio and stretching temperature on pbase transition of melt-spun poly （ vinylidene fluoride ） fibers were investigated and analyzed by using scanning electron microscopy, wide angle X- ray diffraction, differential scanning calorimetry and Fourier transfer infrared spectroscopy. The β phase exists in the as-spun fiber. The β phase content increases as the stretching ratio increases. When the stretching temperature is lower than 100 ℃ , enhancing temperature is good for the transition of phase a to ft. By contrast, when the stretching temperature is higher than 100 ℃ , enhancing temperature is unfavourable for the transition of phase a to β. Increasing the draw temperature increases the α-phase content.