碳/芳纶混编三维编织复合材料拉伸性能

为分析三维编织复合材料拉伸性能和失效机制,分别以碳纤维和芳纶纤维为轴纱和编织纱织造了三维五向、三维六向碳/芳纶混编复合材料。采用数字图像相关法采集试样在单轴拉伸过程中表面全场应变信息得到的泊松比。结果表明：三维编织复合材料泊松比受编织结构的影响较大,同种编织结构下,碳纤维为轴纱的复合材料基本保持了碳纤维三维编织复合材料的拉伸强度和模量,同时提高了断裂伸长率;芳纶纤维为轴纱的复合材料则显著提高了断裂伸长率,但拉伸强度和模量损失较为明显;同种混编方式下,三维五向编织复合材料的拉伸强度和拉伸模量较三维六向高,断裂伸长率无明显差异。编织纱分别为碳纤维和芳纶纤维的三维编织复合材料高应变区分别类似点阵分布和波浪线分布,三维五向和三维六向编织复合材料高应变区分别呈均匀分散分布和横向分布。     

Hybrid Yarns and Textile Preforming for Thermoplastic Composites

In the recent years, the use of textile structures made from high performance fibers is finding increasing importance in composites applications. In textile process, there is direct control over fiber placements and ease of handling of fibers. Besides economical advantages, textile technologies also provide homogenous distribution of matrix and reinforcing fiber. Thus textile performs are considered to be the structural backbone of composite structures. Textile technology is of particular importance in the context of improving certain properties of composites like inter-laminar shear and damage tolerance apart from reducing the cost of manufacturing. Textile industry has the necessary technology to weave high performance multifilament fibers such as glass, aramid and carbon, which have high tensile strength, modulus, and resistance to chemicals and heat into various types of preforms. Depending upon textile preforming method the range of fiber orientation and fiber volume fraction of preform will vary, subsequently affecting matrix infiltration and consolidation. As a route to mass production of textile composites, the production speed, material handling, and material design flexibility are major factors responsible for selection of textile reinforcement production. This opens a new field of technical applications with a new type of semifinished material produced by textile industry. Various types of hybrid yarns for thermoplastic composites and textile preforming methods have been discussed in detail in this issue. Information on manufacturing methods, structural details and properties of different hybrid yarns are presented and critically analyzed. Characterization methods used for these hybrid yarns have been discussed along with the influence of different processing parameters on the properties being characterized. The developments in all areas of textile preforming including weaving, knitting, braiding, stitching and nonwovens techniques are presented and discussed along with the characterization techniques for these preforms. The techniques used for manufacturing composites using hybrid yarns and textile preforms are discussed along with the details on compaction behavior of these structures during consolidation process. The structure of hybrid yarns and the textile preforms have direct influence on the properties of the composite made from them. The reported literature in this aspect is discussed in detail. In the end, the potential application areas and their trends for thermoplastic composites are discussed and analyzed.     

混杂纤维复合材料的研究进展

混杂纤维复合材料作为一种新型复合材料极大地扩展了复合材料的性能和使用范围.对混杂复合材料拉伸性能、冲击性能、热性能、摩擦性能、阻尼减震性能、吸波性能等方面的研究进展进行了综述,并简要介绍了混杂纤维复合材料的应用情况及发展.     

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.     

剪切增稠液/纤维复合材料防弹性能的研究进展

为促进对剪切增稠液(STF)与高性能纤维复合形成具有高效力学响应和能量吸收机制的智能抗冲击防护材料的性能研究和应用,综述了STF流变性能、STF/纤维复合材料力学性能及其抗弹道冲击机制的研究进展,分析了STF原料选择、复合材料体系构建原理及制备方法。针对STF/纤维复合材料的弹道冲击过程和特点及其在高速冲击下的反应机制,探讨影响弹道冲击性能的因素并提出解决方案。展望了高响应度的柔性智能STF/纤维防弹复合材料的研究发展方向,指出对柔性智能STF/纤维防弹复合材料的表征和评价方法尚需完善,基于三维自增强结构、纤维材料与STF界面结合性、流变滑移及摩擦特性是未来防弹复合材料的研究重点。     

废纺再生毡基材料的制备及其性能

为减少废旧纺织品对环境造成的污染,提高废旧纺织品的回收利用率,实现资源利用的最大化,以废旧纺织品经机械处理后得到的回收涤纶、回收麻纤维及低熔点涤纶短纤为原料,采用梳理成网与热风黏合联合工艺,制备再生毡基材料,然后通过正交试验进行工艺优化,并对其厚度、面密度、蓬松度、力学性能、保温性和透气性进行分析,得到最佳制备工艺：回收麻纤维、回收涤纶和低熔点涤纶短纤质量比为15:40:45,温度为180 ℃,时间为8 min,压力为200 N。结果表明：再生毡基材料的厚度为7~10 mm,面密度为300~450 g/m2 ,蓬松度为15~30 cm3/g,透气率为900~1100 mm/s;该再生毡基材料可用于汽车内饰和其他功能性材料的基材。     

含咪唑结构高强高模聚酰亚胺纤维的制备及其结构与性能

为增强聚酰亚胺纤维的力学性能,促进其在复合材料领域的应用,基于高性能聚合物纤维的结构设计,将杂环二胺单体5-氨基-2- (对氨基苯基)苯并咪唑引入到3,3',4,4'-联苯四羧酸二酐和对苯二胺的聚酰亚胺刚性骨架中得到纺丝溶液,通过干法纺丝技术制备得到聚酰亚胺纤维,研究了纤维化学结构和聚集态结构与纤维力学性能的关系,并系统评价了纤维的热性能和抗紫外光辐照性能。结果表明:聚酰亚胺纤维的拉伸强度和初始模量分别达到4.04、130 GPa,这得益于其聚合物分子链沿纤维轴向的高度取向性及分子链间形成的氢键作用;其玻璃化转变温度和热质量损失10%时温度分别为324、587 ℃,经168 h 紫外光辐照后,拉伸强度保持率为92%,具有良好的耐热性和优异的抗紫外光辐照性能。     

Effect of Processing Conditions on Flexural Strength Properties of Chicken Feather Fibre (CFF) and Its Hybrid Composites with Polypropylene Resin

ABSTRACT

This study discusses the effect of molding temperature, pressure and time on the final compression-molded hybrid composites with polypropylene resin for its flexural strength. The results of tests conducted to characterize the hybrid composites developed with different proportion of fibers and processing conditions are discussed in this study. When comparing the overall results on the flexural strength of the composites, 25:75 Chicken Feather Fiber (CFF)/Jute composite showed highest flexural strength by keeping minimum temperature, maximum pressure and medium time. The influence of pressure on flexural strength is significant compared to temperature and time. As time increases the flexural strength decreases.     

生物基锦纶56用抗静电纺丝油剂的复配及其对短纤维可纺性的影响

针对生物基锦纶56(PA56)短纤维质量比电阻大,静电严重,可纺性差的问题,采用市售油剂和抗静电剂复配技术开发了抗静电性、集束性、可纺性较好的生物基PA56纺丝油剂。研究了抗静电剂质量浓度对复配油剂电导率、pH值的影响,考察了经复配油剂处理后PA56纤维的表面形貌、摩擦因数、质量比电阻及梳理机成网加工性能。结果表明:复配油剂在纤维表面形成一层光滑、均匀的油膜;复配纺丝油剂中抗静电剂质量浓度在2 g/L、市售油剂质量浓度在12 g/L为宜,经处理的PA56纤维在相对湿度为35%,室温下可顺利梳理成网,且纤维网均匀、无破洞、云斑;该油剂复配方案提升了锦纶的集束性、抗静电性、可纺性,节能环保,对纺纱车间温湿度要求低。     

高性能纤维的单纤维压缩弯曲性能

选取11种高性能纤维,包括PBO纤维、芳纶1313纤维、对位芳纶纤维、高强聚乙烯长丝和高强聚乙烯短纤等,采用单纤维压缩弯曲仪测试纤维的单纤维压缩弯曲性能,并对其压缩弯曲曲线进行对比分析。结果表明,11种高性能纤维中,Technora纤维的最大力和抗弯刚度最大,在相同条件下,Technora纤维更难被压弯;PBO纤维普通丝的抗弯刚度远大于高模量丝的抗弯刚度;直径相同的条件下,芳纶1414纤维的最大力、等效弯曲模量及抗弯刚度明显高于芳纶1313纤维;超高分子量聚乙烯纤维的压缩弯曲曲线变化趋势最明显。     

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。     

Mechanical,morphological, and thermogravimetric analysis of alkali-treated Cordia-Dichotoma natural fiber composites

ABSTRACT

Usage of composites with natural fiber reinforcement is drastically increasing in recent times because of their low density, biodegradable nature, and low cost. However, natural fibers have certain core problems such as poor adhesion between the fiber and matrix and a relatively high degree of moisture absorption. Alkaline treatment of natural fibers is aimed at improving the adhesive strength so that effective stress transferability takes place in the composite. In the present work, Cordia-Dichotoma fibers were treated with sodium hydroxide (NaOH) and composites were prepared with different weight ratios of these fibers reinforced with epoxy. The prepared composites were tested for their tensile and flexural strengths (mechanical properties). Besides, for a comprehensive material characterization, IR spectroscopy (FT-IR), scanning electron microscope, and thermogravimetric analysis were carried out. This work investigates the influence of aforementioned NaOH treatment on thermal, mechanical, and morphological properties of the composite material.     

Properties of recycled poly (ethylene terephthalate) (PET)/hyperbranched polyester (HBPET) composite fibers

Hyperbranched polyester (HBPET) with aliphatic–aromatic structure was synthesized and extruded with recycled poly (ethylene terephthalate) (RPET) chips obtained from used water bottles, with ratio of 0.5% and 1?wt% of HBPET. Filament fibers from pure recycled PET (RPET-0) and (RPET-0.5 and RPET-1) composite were spun using a melt spinning process and drawn by a thermal drawing process to improve their mechanical properties. The effects of addition of HBPET on the properties of produced fibers as well as draw ratio are investigated by means of differential scanning calorimetry (DSC), wide-angle X-ray diffraction (XRD), universal tensile analysis, and sonic velocity. It was found that mechanical properties of the (RPET-0.5 and RPET-1) fibers were improved with respect to pure recycled PET (PET-0) fibers. Moreover, the crystallinity of composites fibers was also increased with an increasing of HBPET content. The improvement in mechanical properties may be due to the increase of orientation of fiber molecules along the fiber axis. Moreover, addition of HBPET serves as lubricant within recycled PET matrix which increased its mechanical properties.     

纺织品在风力发电机叶片中的应用

介绍了风力发电机上使用的纺织复合材料种类以及成型方法.纺织复合材料特有的优异性能使其在风力发电机叶片上得到广泛应用,并使制造单机容量更大的风力发电机成为可能.单机5 MW的机组已经安装运行,7 MW的机组已经研究成功.纤维材料由玻璃纤维向碳纤维、混杂纤维发展;树脂材料逐渐采用可回收的热塑性材料;纺织品由经纬交织的机织物...     

用于非织造材料的Tencel Lyocell纤维

Lenzing纤维公司开发的Lyocell纤维构成了一个纤维产品系列,用于要求具有吸湿性、纯度、柔软性、强度和生物降解性的各种各样非织造产品.述评了长度短的短纤维(低于20 mm)的特性和制得的织物的性质,重点是如何能利用上述纤维设计高性能非织造材料的重要产品性质.     

Fabrication and Characterization of MWCNT Filled Hybrid Natural Fiber Composites

Hybrid composites are fabricated by the combination of two or more fibers using a single matrix. It can be fabricated either with all of its constituents as natural fibers or with one or more constituents belonging to artificial fiber. The stacking sequence of the fibers in a hybrid composite can be altered resulting in a varying mechanical properties. In the present study the MWCNT filled banana-jute-flax fiber reinforced composites are investigated for its mechanical behavior by varying the stacking sequence of the fiber layers and weight % of Multi-Walled Carbon Nano Tube (MWCNT). A Modified resin was prepared by adding MWCNT in the epoxy resin using ultrasonic probe sonicator and a hybrid composite is fabricated with it by using compression moulding processes. The mechanical properties are evaluated as per the ASTM standards. The incorporating of MWCNT and the stacking sequence of fiber layers shows the greater impact on the mechanical properties. The composites of jute fibers at the extremities (JBFBFBFJ) exhibiting the enhancement of tensile, compressive and hardness properties than the flax fiber at the extremities (FBJBJBJF) and it could be used in various automobile applications. Microstructure of the samples are investigated by Scanning Electron Microscope (SEM)with Energy dispersive X-ray (EDS). The results indicate that increasing the weight % of MWCNT and varying the stacking sequence of fibers improves the mechanical properties of hybrid natural fiber composites.     

水刺非织造布专用涤纶短纤维性能的研究

分析了普通棉型涤纶短纤维、水刺专用一般亲水涤纶短纤维、水刺专用高亲水涤纶短纤维的结构和性能,研究表明亲水处理对水刺专用涤纶短纤维的表面形态、摩擦性能、比电阻、吸湿性能等有较大的改善,介绍了3种涤纶短纤维在水刺非织造布产品中的应用特点。     

Recycling of cotton and polyester fibers to produce nonwoven fabric for functional sound absorption material

Recycled fibers are commonly used in dissimilar applications and one of the most important applications is sound absorption. Recycled fiber nonwovens currently are in greater demands in industries because of their advantages such as low cost, biodegradability, acceptable mechanical and physical properties, and so on. Sound absorption materials, renewable, and eco-friendly nonwovens have been developed using recycled cotton and polyester fibers. This research provides a contribution to the body of knowledge on the sound absorption properties of nonwovens using recycled fibers which contain cotton and polyester by means of spun-laid technique and provides a better understanding of the effects of a number of manufacturing processes on nonwovens noise control performance and also contributes to the wider adoption of nonwovens as sound absorbers. The sound absorption coefficients were measured according to ASTM E 1050 by an impedance tube method. The results revealed that the average of the sound absorption coefficients increased with the thickness of the nonwovens, but decreased with the nonwoven fabric density.     

Hybrid Composites Made from Jute/Coir Fibers: Water Absorption,Thickness Swelling,Density, Morphology,and Mechanical Properties

The action of water in natural fiber-reinforced composite material was studied so as to produce great swelling with resultant changes in the fine structure, dimensional stability, and mechanical properties. Water absorption and thickness swelling test reveal that hybrid composite shows water absorption moderately, which is 15.3% for hybrid coir/jute/coir composite and 11.2% for hybrid jute/coir/jute composite. The thickness swelling, water absorption, and mechanical properties of the hybrid composites slightly increased as the layering pattern of hybrid composites changed. Hybridization of coir fibers composites with jute fibers can improve the dimensional stability, extensibility and density of pure coir composites. Microstructures of the composites were examined to understand the mechanisms for the fiber-matrix interaction in relation to mechanical properties.     

热分散机高浓磨浆的可行性探讨

将热分散机的普通磨片改用高浓磨浆磨片,测试普通磨片与高浓磨片处理对废纸浆撕裂度、抗张强度、抗张能量吸收的影响,探讨了热分散机高浓磨浆的可行性.