再生聚酯切片生产缝纫线用涤纶短纤维的工艺研究

以物理法再生聚对苯二甲酸乙二醇酯(PET)切片为原料,通过纺丝-拉伸法制备涤纶拉伸丝,从切片的外观特点、过滤性能、特性黏数及流变性能,以及拉伸丝的性能考察原料的可纺性及相应的纺丝、拉伸工艺要求;在此基础上以再生PET切片为原料,在现有常规涤纶短纤维间接纺生产线上生产缝纫线用再生涤纶短纤维,探讨了其生产工艺条件。结果表明：粒子形状规整、过滤性能较好、特性黏数较高的再生PET切片具有良好的可纺性,纺丝过程中需根据切片的特性黏数调整纺丝温度,拉伸过程中需适当提高拉伸温度;采用特性黏数为0.737 dL/g的再生PET切片为原料生产1.33 dtex×38 mm缝纫线用再生涤纶短纤维,与以原生PET切片为原料相比,螺杆熔融温度提高8℃,箱体温度提高5℃,拉伸温度和定型温度分别提高3～5℃;通过生产调控,生产稳定性好,生产的短纤维断裂强度达到6.1 cN/dtex,其他质量指标达到原生涤纶短纤维优等品要求。     

粘合性能对短纤维-氯丁橡胶复合材料耐热性的影响

该文以尼龙短纤维为例研究了短纤维的不同用量及其粘合性能对短纤维-CR复合材料的力学性能和耐热老化性能的影响;并研究了尼龙短纤维-CR复合材料的耐溶胀性能。实验结果表明：随着尼龙短纤维用量的增加,短纤维-CR复合材料的硬度、撕裂强度、20％定伸应力不断提高;短纤维与橡胶基质的粘合好,耐溶胀性能明显提高,对橡胶的补强效果更好,复合材料的耐热老化性能提高。     

短纤维补强氯丁橡胶的性能研究

研究短纤维种类和用量对短纤维/氯丁橡胶(CR)复合材料中短纤维取向和分散以及复合材料粘合性能和溶胀性能的影响.结果表明:随着短纤维用量的增大,短纤维/CR复合材料的相对交联密度和短纤维取向度均增大,抗溶胀性能提高,取向度大小顺序为芳纶短纤维、聚酯短纤维、锦纶66短纤维和短切棉纤维;聚酯纤维与CR基体的粘合性能最差,短切棉纤维在CR中分散性最差;短纤维/CR复合材料的性能呈现出明显的各向异性.     

中国石化首条聚苯硫醚短纤维生产线建成投产

<正>中国石化首条聚苯硫醚短纤维生产线于2012年2月17日在天津石油化工有限责任公司一次开车成功。产品一面世即引起工业领域特别是高温过滤领域的关注,成为燃煤电厂烟道气除尘和城市垃圾焚烧厂尾气过滤的首选滤材。PPS纤维的诸多优异性能使其用途不断被开发,     

短纤维增强丁腈橡胶复合材料性能的研究

研究几种短纤维部分替代炭黑对丁腈橡胶(NBR)复合材料性能的影响。结果表明:非极性聚酯短纤维胶料的FL和Fmax较小,刚性芳纶短纤维胶料的FL和Fmax较大;与无短纤维胶料相比,短纤维胶料的t10较长,门尼粘度较低,硬度较大,300%定伸应力和拉伸强度较低;沿短纤维取向垂直方向比沿短纤维取向方向胶料的拉伸强度和拉断伸长率较低;短纤维在NBR胶料中的取向程度及其胶料刚性和硬度由大到小的顺序为:芳纶短纤维、聚酯短纤维、聚酰胺纤维和纤维素短纤维;芳纶短纤维胶料的抗撕裂性能较好,聚酯短纤维胶料的综合性能较好;短纤维胶料易发生屈服,短纤维易成为材料破坏的应力集中点。     

湿法混炼芳纶短纤维/丁腈橡胶复合材料的性能研究

用湿法混炼方法制备了芳纶短纤维/丁腈橡胶(NBR)复合材料,研究增稠剂和芳纶短纤维用量对复合材料性能的影响。结果表明:添加聚丙烯酸钠(PNaAA)和聚氧化乙烯(PEO)两种增稠剂有利于提高芳纶短纤维的分散性,添加质量分数为0.007 5 PNaAA的复合材料拉伸性能最好;随着芳纶短纤维用量的增大,复合材料的拉伸性能先提高后降低;芳纶短纤维用量为2份时,复合材料的拉伸性能总体最好,芳纶短纤维补强效果最佳。     

玄武岩短纤维/硅橡胶复合材料性能研究

采用玄武岩短纤维补强硅橡胶,研究玄武岩短纤维/硅橡胶复合材料的性能。结果表明:用丙酮脱玄武岩短纤维表面的浆膜,处理时间为50 min时效果最佳;用偶联剂KH-550对玄武岩短纤维表面进行处理,且玄武岩短纤维用量为20份时,玄武岩短纤维/硅橡胶复合材料的综合性能最佳;制备玄武岩短纤维/硅橡胶复合材料的最佳硫化条件为175℃/10 MPa×25 min。     

短纤维替代炭黑对丁腈橡胶胶料性能的影响

研究几种短纤维部分替代炭黑对丁腈橡胶（NBR）胶料性能的影响。结果表明：非极性聚酯短纤维胶料的FL和Fmax较小,刚性芳纶短纤维胶料的FL和Fmax较大;与无短纤维胶料相比,短纤维胶料的t10延长,门尼粘度低,硬度大,300%定伸应力和拉伸强度较低;沿短纤维垂直取向方向比沿短纤维取向方向胶料的拉伸强度和拉断伸长率较低;短纤维在NBR胶料中的取向程度及其胶料刚性和硬度由大到小的顺序为：芳纶短纤维、聚酯短纤维、聚酰胺纤维和纤维素短纤维;芳纶短纤维胶料的抗撕裂性能较好,聚酯短纤维胶料的综合性能较好;短纤维胶料易发生屈服,短纤维易成为材料破坏的应力集中点。     

聚苯硫醚纤维和亚克力纤维梯度复合过滤毡

一种聚苯硫醚纤维和亚克力纤维梯度复合过滤毡,该过滤毡是在聚苯硫醚短纤维织成的基布上、下两层铺设混合纤维层和亚克力纤维层,在上面一层混合纤维层表面再铺设一层聚苯硫醚纤维层。本实用新型的优点是过滤精度高、清灰效果好、透气性能好、机械强度大、耐腐蚀性能强。     

功能性超细石墨粘胶短纤维的制备及性能研究

以粘胶短纤维为基体,超细石墨为功能添加剂,采用纺前注射技术制备功能性超细石墨粘胶短纤维,并对该纤维的形态结构、结晶结构、热学性能以及抗静电性能进行测试分析。结果表明:超细石墨粘胶短纤维横截面呈锯齿状,纵向表面有沟槽,超细石墨在纤维中均匀分布;超细石墨与粘胶短纤维基体具有良好的共混性和相容性;与普通粘胶短纤维相比,功能性超细石墨粘胶短纤维具有更好的热稳定性和抗静电性能。     

Short-Fiber Chromatography Columns: Potential for Process-Scale Bioseparations

Abstract

Chromatographic supports with short-fiber geometry have been evaluated for process-scale applications. Using a prototype silica-based ion-exchange fiber and bovine serum albumin as the model biomolecule, a comparison of the throughput characteristics of fiber columns with those of conventional columns (spherical packing) has been made. The comparison accounts for the influences of pressure drop, adsorption thermodynamics, and mass transfer. It has been shown that retention characteristics, mass dispersion, and intraparticle mass-transfer resistance are critical in determining which column has a higher throughput. In general, if the capacity factor of the desired product is high, it is predicted that the fiber column will give higher throughputs, except for separations that involve closely eluting impurities. Based on these results, guidelines detailing desired properties of short-fiber chromatographic supports are provided.     

Preparation and characterization of braided tube reinforced polyacrylonitrile hollow fiber membranes

Polyacrylonitrile (PAN) and polyester (PET) braided hollow tube that used as a special reinforcement are braided from their filaments via two‐dimensional weaving techniques. PAN braided tube reinforced homogeneous PAN hollow fiber membranes and PET braided tube reinforced heterogeneous PAN hollow fiber membranes are prepared by concentric circles squeezed‐coated spinning method. As for PAN hollow fiber membrane, the effects of PAN concentration on the performance of the prepared hollow fiber membranes are investigated in terms of pure water flux, protein rejection, mechanical strength, and morphology observations by a scanning electron microscope (SEM). The interfacial bonding state of the braided tube reinforced PAN hollow fiber membranes is studied by constant speed stretching method. Results show that the breaking strength of two‐dimensional braided tube reinforced PAN hollow fiber membranes is higher than 80 MPa. The structure of separation surface is similar to the structure of an asymmetric membrane. With the increase of polymer concentration, the membrane flux decreases while the retention rate of BSA increase. The membrane porosity and maximum pore size have the same decreasing tendency as the increase of PAN concentration. The results also show that the interfacial bonding state of the PAN two‐dimensional braided tube reinforced homogeneous PAN hollow fiber membranes is better than that of the PET two‐dimensional braided tube reinforced heterogeneous PAN hollow fiber membranes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41795.     

Effects of interphase conditions on the tensile and fatigue properties of short-fiber reinforced rubber

The effects of the amount of nylon-66 short-fiber and its bonding to a chloroprene rubber were studied. The following results were obtained: (a) The tensile strength of short-fiber reinforced rubber (SFRR) exhibits a dilution effect in each interphase. It was found that the interphase conditions have an important effect on the dilution ratio and the critical fiber content. The specimen with double coatings of the bonding agent and a rubber solution, becomes the best of 5 interphase models. Both the yield strength and tensile moduli significantly improve with fiber content. (b) The spring constant (SC) of unreinforced rubber decreases after the fatigue test, however, the SC of all reinforced rubbers increases. The change in SC of reinforced rubber decreases with fiber content. The better the interphase condition, the smaller the change of the SC. (c) The temperature of rubber increases about 2.6 fold after the fatigue test. The reinforced rubbers show a 1.4 to 2.2 fold increase in temperature. The temperature changes during the fatigue test of the reinforced rubbers decrease with increasing fiber content, as well as with improved interphase bonding.     

基于细观力学的短纤维增强复合材料断裂性能数值研究

基于细观力学,采用虚拟裂纹扩展结合有限元法计算了短纤维增强复合材料纤维端部不同方向裂纹的应变能释放率,研究了网格尺寸对应变能释放率计算结果的影响,并分析应变能释放率随裂纹长度,纤维的长度、半径和含量的变化关系。研究表明:网格尺寸对应变能释放率的计算结果影响小;不同区域的裂纹,其应变能释放率受裂纹长度的影响不同;应变能释放率随裂纹扩展方向变化曲线呈对称特点,其中滑移型裂纹的扩展阻力较小;应变能释放率随着纤维长度、半径和含量的增大而增大。     

Fiber fracture in reinforced thermoplastic processing

The length reduction of reinforcing fibers in short-fiber reinforced plastics during processing has been studied experimentally. It has been shown that fiber volume fraction, initial length, and initial state of dispersion have little effect on the final fiber length. In dilute suspension theory based on shearing flow conditions and fiber properties the flow stresses are found to be compatible with the experimental results and results which are found in the literature.     

影响长纤维增强热塑性塑料注塑制品中纤维长度的主要因素

长纤维增强热塑性塑料力学性能比普通短纤维增强塑料有很大的提高，注射成型中保持纤维的长度是关键。本文对长纤维增强热塑性塑料(LFT)注射工艺进行了简要绍，并对影响纤维长度的设备及工艺方面的因素进行了总结。     

Void formation in short-fiber thermoplastic composites

Voids, or bubbles, are formed in short-fiber thermoplastic composites because of entrapment of air in the compounding and melt flow processing steps and as a result of uneven shrinkage due to temperature gradients involved in the solidification step by cooling. The experimental results suggest that bubble nucleation takes place at fiber ends and their volume content depends on processing conditions. The shape and distribution of the voids were studied by optical examination of longitudinal sections of extrudates, using standard metallographic polishing technique and reflected light microscopy. The void volume fraction of extrudates was found to increase with increasing extrusion rate, temperature, fiber concentration, and fiber length, and with a decreasing draw ratio. The void content in fiber-glass-reinforced injection moldings is low, ≈︁1% by volume; however, by heating these moldings, the contained pressurized bubbles expand and significant void volume fractions are observed.     

Bismuth‐Doped Multicomponent Optical Fiber Fabricated by Melt‐in‐Tube Method

Bismuth‐doped multicomponent optical fiber was fabricated by a melt‐in‐tube method. The fiber was prepared at drawing temperature where the clad was softened, while the fiber core glass was melted. The obtained fiber was characterized by electroprobe microanalyzer and X‐ray diffraction. No obvious precipitation of crystals or bismuth metals was observed in the fiber. Excited by 808‐nm laser, intense broadband near‐infrared emission with full width at half maximum of about 325 nm was observed from the fiber. Consequently, this fiber is promising for broadband fiber amplification. The melt‐in‐tube method is generally applicable for fabricating bismuth‐doped multicomponent optical fiber.     

Microstructure of long- and short-fiber reinforced injection molded polyamide

The variation of fiber orientation and content within injection molded rectangular plates is investigated. Fiber orientation and volume fraction are measured using metallographic polishing and a newly developed image-analysis system; fiber weight-fractions are measured using an ashing method. Three different moldings are studied; two of the long-fiber compound Verton, Molded at different injection speeds, and one of the short-fiber compound Maranyl. Microstructural regions are identified and characterized, and the flow mechanisms by which they are formed are discussed. The results show that the long fibers segregate extensively, whereas the short ones do not. The major differences between the two compounds are found in the core: the core of the long-fiber compound has a higher content and orientation of fibers than that of the short-fiber compound.