Impact properties of thermoplastic composites

The excellent properties exhibited by thermoplastic composites at much reduced weight have attracted attention in the development of products in different sectors. Thermoplastic (TP) composites, because of their distinctive properties as well as ease of manufacturing, have emerged as a competitor against the conventional thermoset resin-based composites. Depending on the application, these composites may undergo impact events at various velocities and often fail in many complex modes. Hence, the development of TP composites having high energy-dissipation at (the desired) much-reduced weight has become a challenging task, but it is a problem which may be alleviated through the appropriate selection of materials and fabrication processes. Furthermore, fibre surface modification has been shown to increase fibre-matrix interfacial adhesion, which can lead to improved impact resistance. Textile preforms are helpful in acting as a structural backbone in the composites since they offer a relatively free hand to the composite designer to tailor its properties to suit a specific application. Additionally, hybrid textile composite structures may help in achieving the desired properties at much lower weight.

Simulation software can play a significant role in the evaluation of composites without damaging physical samples. Once the simulation result has been validated with actual experimental results, it should be possible to predict the test outcomes for different composites, with different characteristics, at different energy levels without conducting further physical tests. Various numerical models have been developed which have to be incorporated into these software tools for better prediction of the result.

In the current issue of Textile Progress, the effects of various materials and test parameters on impact behaviour are critically analyzed. The effect of incorporating high-performance fibres and natural fibres or their hybrid combination on the impact properties of TP composites are also discussed and the essential properties of TP polymers are briefly explained. The effects of fibre and matrix hybridization, environmental factors, various textile preform structures and fibre surface modification treatments on the impact properties of thermoplastic composites are examined in detail. Various numerical models used for impact analysis are discussed and the potential applications of TP composites in automobile, aerospace and medical sectors are highlighted.     

3D woven green composites from textile waste: mechanical performance

Application of textile waste for development of value added green composites has been carried out in this work. Textile fabric waste is collected from various sources. These waste materials are garneted, so as to produce loose fibrous material, subsequently this fibrous material was converted into twisted strand for manufacturing of 3D woven preforms for production of composites. Twisted strands are converted into orthogonal 3D woven structure. The fibers extracted from waste material are combined with polypropylene in 60/40 proportion. Composites of various specifications are developed to examine their end-use applications. These composite materials are characterized for their mechanical behavior to find out the response against tensile loading, flexural stress, and impact force. The effects of moisture absorption on mechanical properties of composites are investigated. 3D woven fabric reinforced composites produced by using waste fiber yarn and normal cotton OE yarn do not exhibit any significant difference in the mechanical behavior of composite. This result confirmed that waste material can be safely used as reinforcing structure in green composite manufacturing.     

玄武岩纤维多重针织结构复合材料的弯曲性能分析

将两种不同针织结构的材料按一定方向和顺序进行叠加并用玄武岩纤维纱手工缝合.对缝合与不缝合的增强体采用真空辅助树脂转移模塑成型(VARTM)工艺加工制成复合材料,测试了两种复合材料的纵横向弯曲性能.结果表明,弯曲方向上受力纱线根数的不同是造成经纬向弯曲性能差异的原因,缝合复合材料的单位纤维体积分数的弯曲强度与模量要比未缝合复合材料的大,缝合显著改善了复合材料的分层现象.     

Non-destructive infrared inspection of dry multilayer carbon fibre preforms

Thermography was used for performing non-destructive inspection of dry carbon fibre textile preforms used in manufacturing carbon fibre polymer-matrix composites (CF-PMCs). The aim was to probe the feasibility of identifying defects in thick carbon fibres preforms made from multiple layers of industrial textile reinforcements, before composites are manufactured. Inspecting dry preforms will not replace the inspection of final CF-PMC parts but it can avoid costly and wasteful manufacturing of CF-PMC parts from defective preforms, as the defects sought in this paper cannot be observed by visual inspection. The preforms tested were made of two or four layers of industrial carbon fibre textile reinforcements. They featured defects of different widths, types and orientations. Results show that thermography can identify defects in preforms successfully, and that detection is influenced by the orthotropic thermal conductivity of carbon fibres, by yarn and fabric architecture, by the relative orientations of defects and yarns, and by the number of layers.     

三维机织预型件的织造技术

纺织复合材料预型件的生产工艺有多种,其生产路径主要由最终用途决定。三维机织物是通过对传统织造原理改进加工而成的。二维机织复合材料是一种由二维织物构成的层合材料,而三维机织复合材料是复杂几何结构的整体构件。三维机织复合材料预型件有许多优点,最重要的优点是它避免了二维层合材料的分层现象。介绍了三维机织预型件的织造方法,为纺织复合材料的开发提供了有益的借鉴。     

热拉式多材料纤维光电子技术研究进展与展望

随着纺织工程和材料科学的快速发展,智能纤维与织物以其柔软、轻便、透气等优势成为可穿戴设备的首选载体。热拉式多材料光电子纤维有望通过热拉制工艺发展为具有多参量感知、温度调控、信息交互等功能的智能纤维。为使热拉式多材料光电子纤维可更好地服务于纺织行业,重点讨论了热拉式多材料纤维光电子技术的研究进展,总结了热拉纤维内微纳结构的调控机制,阐述了热拉式多材料纤维在传感、能源、生物、医疗等场景中的应用,并展望了热拉式多材料纤维光电子技术未来在材料选择及研发、纤维结构调控、纺织加工、多功能集成、人工智能5个方面的研究趋势。最后指出：热拉式多材料光电子纤维未来将从单一功能向多功能、力学性能改善、智能计算等方向发展,以便更好地与传统纺织加工技术结合,进一步提升织物的功能性、穿戴舒适性、场景普适性。     

产业用纳米改性PA6纱

由德国联邦教育与研究部(BMBF)出资的研究项目--由纳米改性混合纱制得的NanoOrgano可覆盖预成型件生产纤维增强热塑性塑料(FRT)--目前正处在半浸渍热塑性预成型件的研制阶段.该种预成型件能同时固化和成型.为改善复合物的抗冲击性能和拉伸强度,另外用纳米粒子对热塑性组分进行了改性.     

Assessment of key issues in the coloration of polyester material

In a previous publication we reviewed some of the most critical issues that affect the coloration and properties of cotton-based textiles [R. Shamey and T. Hussain, Textile Progress 37(1/2) (2005) pp. 1–84]. Today, polyester is still widely regarded as an inexpensive and uncomfortable fiber, but this image is slowly beginning to fade with the emergence of polyester luxury fibers. Polyester fibers currently comprise a commanding 77% share of the total worldwide production of the major synthetic fibers [F. Ayfi, 2003–2004 Handbook of Statistics on Man-Made/Synthetic Fibre/Yarn Industry. Part One, Fibre for Better Living, Association of Synthetic Fibre Industry, Mumbai, India, 2004, p. 177]. More than 95% of all polyester fibers manufactured today is based on polyethylene terephthalate. The dyeing properties of polyester fibers are strongly influenced by many of the processing conditions to which each fiber may be subjected during its manufacturing or in subsequent handling. Significant differences in properties of fibers can therefore arise due to their different processing history. Often, the root cause(s) of a problem in the dyed synthetic material can be traced as far back as the manufacturing process. In order to resolve many of the outstanding issues that commonly occur in the dyeing of this important fiber, a comprehensive review of the issues dealing with the manufacturing history as well as fiber processing conditions, including preparation, dyeing, and finishing is warranted. Although some of the underlying problems are related to common causes such as water quality and imperfections in machinery employed, others are specific to the treatment conditions of the fiber. Such conditions include preparation of ingredients, polymerization, fiber and filament processing conditions, as well as heat setting that can cause problems in the coloration of fiber. This summary analysis complements the rich pool of knowledge in this domain and addresses problems in the dyeing of polyester textile materials in various forms. An overview of various textile operations for polyester is given in the beginning. Then, various key steps and critical factors involved in the production of dyed polyester textile materials are described in detail and problems originating at each stage are summarized.     

三维纺织复合材料的结构特点和应用

本文主要讨论了三维纺织预制件及其复合材料的结构特点。由于三维纺织复合材料的纤维在三维空间相互交织和交叉 ,形成了一个不分层的整体结构 ,所以它和层合复合材料相比具有优良的层间性能和其他力学性能 ,可制作第一承力结构件和高功能制件。本文还介绍了树脂基三维纺织复合材料的复合固化技术以及三维纺织复合材料的一些应用 ,说明它具有广泛的应用前景。     

X-ray-protective organic/inorganic fiber – along the textile chain from fiber production to clothing application

High X-ray absorption and, therefore, excellent X-ray protection properties are related to heavy chemical elements. Therefore, a composite fiber for X-ray protection applications was developed consisting of an organic cellulose part and an inorganic part. Whereas the preceding part provides the common properties connected to fibers and the latter part ensures the X-ray protection effect. The treatment of this composite fiber along the whole textile chain is presented and the possible usage as a common textile fiber in spinning and knitting processes is impressively demonstrated. Textile properties such as air permeability and abrasion stability are successfully tested. Furthermore, the microscopic structure is characterized by means of optical and scanning electron microscopy. The X-ray protective properties are determined by transmission experiments. The realization of a textile product is shown by production of a glove, where protective properties are impressively shown by 3D X-ray tomography. Altogether, the complete production process of X-ray protective textile products using organic/inorganic composite fibers is introduced. Immanent to the presented material are the broad opportunities for developing textile products for X-ray protective applications in medicine, security technology, or materials analytics.     

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.     

复合纱针织物复合材料最佳成型厚度估算

为了确定针织增强热塑性复合材料热压成型时的最佳成型厚度,采用复合纱的方法,通过理论分析和推导,得到了用增强纤维和热塑性基体纤维的线密度和体积密度、复合纱中2种纤维的股数以及复合纱针织预制件的线圈总密度和线圈长度表示的复合材料理论热压成型厚度计算公式,并通过实验确定了实际最佳成型厚度与理论成型厚度之间的关系,为复合纱针织增强热塑性复合材料的制备提供了参考依据。     

Development and characterization of jute/polypropylene composite by using comingled nonwoven structures

High melt viscosity of thermoplastic matrices hinders the impregnation of fibers and their consolidation during fabrication of composites. In the present study, matrix (polypropylene) and reinforcement (jute) fibers were comingled at fiber to fiber level (fiber to matrix ratio of 30, 40, 50 and 60%) while making their nonwoven fabrics using dry laid process. Thermoforming process, in which polypropylene fibers are used and then melted for the development of composite plates. The results showed that the composite samples with 0.30 fiber volume fraction have higher mechanical properties (flexural, impact energy), while samples with 0.40 fiber volume fraction have higher tensile properties (tensile strength and modulus) due to good impregnation of fiber and better fiber-matrix interface. The composite having 0.30 fiber volume fraction has lowest value of moisture regain and diffusion coefficients than the other samples. Voids present in the microscopic images also confirmed the weak interface, when the fiber volume fraction increased up to 0.60.     

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...     

制备工艺对黄麻/聚丙烯针织复合材料性能的影响

 本文讨论了不同工艺黄麻横机针织物增强聚丙烯复合材料的制备工艺对其力学性能的影响。首先利用针织的方法在横机上分别织造黄麻1+1罗纹、畦编、半畦编织物作为复合材料的增强体,分别以3层和5层进行同向铺层、不同质量配比与聚丙烯（PP）纤维均匀混合后通过热压工艺制成复合材料。对所制备的复合材料板材拉伸及弯曲性能进行测试与分析。研究结果表明：在复合织物均为1+1罗纹时,其复合板材性能以3层1+1罗纹6/4的配比为最佳;相同配比,相同层数情况下,畦编组织板材性能则最优;对于相同配比1+1罗纹板材3层性能优于5层。     

PTT的生产加工技术及其应用

综述了国内外在PTT长丝和短纤维加工方面的研究成果，并介绍了PTT在纤维和地毯丝领域、热塑性工程塑料领域、非织造布领域以及其他领域的广泛应用。     

废弃纤维吸声复合材料的制备及其吸声性能

针对废弃纺织纤维利用率不高的问题,采用共混-热压工艺,以废弃纤维为增强材料,以热塑性聚氨酯为基体材料,制备废弃纤维/聚氨酯复合材料。将废弃纤维/聚氨酯复合材料加工成穿孔板,并与废弃涤纶织物贴合,构成吸声复合材料。重点研究吸声复合材料中穿孔直径、穿孔板厚度、穿孔率及废弃涤纶织物层数四种结构参数对材料吸声性能的影响。结果表明,穿孔直径主要影响吸声材料的吸声系数峰值;穿孔板厚度、穿孔率和废弃涤纶织物的层数主要影响吸声材料的吸声频带范围。     

Investigation of electrical,electromagnetic shielding,and usage properties of woven fabrics made from different hybrid yarns containing stainless steel wires

This paper reports the results of a detailed study about specific properties of hybrid yarns and woven fabrics containing those yarns. For this aim, the fabrication procedures and physical properties of acrylic/stainless steel (SS) and cotton/acrylic/SS ply yarns were presented, and then, relations between those and electrical, electromagnetic shielding effectiveness (EMSE) and some usage properties of woven hybrid fabrics made from those with different constructions were investigated. EMSE of plain and twill fabrics were evaluated against radiating electromagnetic wave spectrum over a frequency 0–3000?MHz. A comparison of physical properties of yarns regarding wire diameter and the use properties of fabrics regarding weave type, wire diameter, and yarn type measured were presented. The functional textile products of complex applications can be achieved with low cost, easily since those yarns and fabrics were produced on conventional textile manufacturing machines with small modifications. The present study indicated that use of SS wire-based yarns in fabrics significantly increased the air permeability, pilling resistance, thermal resistance, and the flexural rigidity of hybrid fabrics. The plain weave fabrics exhibited higher EMSE values over 20?dB in higher frequencies and higher thermal absorbtivity values compared to twill fabrics.     

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。     

Survey and Recent Report on Enzymatic Processing of Bast Fibers

SUMMARY

In reference to previous presentations during meetings of Working Group 2 (WG2): “Bioprocessing of Bast Fibres,” acting within the COST Action 847 Project “Textile Quality and Biotechnology,” a further update of current world knowledge on biological processing of fiber plants and textiles was prepared. This survey covers the research on utilization of particular groups of enzymes in these processes. Main areas of enzyme application in bast fiber textile industry, according to literature from 2001-2004 are: degumming of bast fibers and scouring in textile industry (before and after bleaching).

The report also covers the results of studies on enzymatic processing of fiber plants carried out at the INF, in which the work is continued on application of enzymes in: degumming of flax straw, modifying of the short technical flax fibers, linen and hemp fabrics modification, and bonding of lignocellulosic composites.