热塑复合材料弯曲强度测试系统分析(一)

对研发中心现行的热塑性复合材料力学性能测试系统进行了分析,对测试数据位置效应和离散效应进行了研究,采用控制图研究了不同玻纤含量和试验顺序下控制限宽度的变化,以定量的方式反映了当前测试系统所存在的问题。     

聚丙烯HT40S熔融指数测定(MFR)重复性和再现性的研究

就HT40S牌号热熔性塑料熔融指数的测定,通过优化分析操作条件,如试样质量、负荷加载时间、试验温度恒定、试样压实程度等方面,进行了精细化研究性试验,总结出HT40S牌号热熔性塑料熔融指数测定的重复性和再现性,用于指导实际分析工作。     

关于抗冲击聚苯乙烯(PS-1)悬冲强度测试结果再现性的探讨

抗冲击聚苯乙烯(PS-1)悬臂梁缺口冲击强度测试是与制样、环境状态调节、铣缺口、测试环节等多个要素相关的条件实验,这些实验条件直接影响了冲击强度的再现性.由于仪器等条件限制,目前国内各生产厂家执行的制样及检测标准不完全一致,导致分析结果可比性差.本文注重讨论如何提高 PS-1悬臂梁冲击强度测试结果的再现性问题,使不同生产企业的抗冲击聚苯乙烯(PS-1)的悬臂梁冲击强度结果有较好的可比性.     

精密度试验及设计(上)

以重复性和再现性为主要内容的精密度,是构成测量（包括化学分析）方法标准的技术内容之一。建立方法标准的重复性和再现性界限值需要通过精密度试验。对精密度试验已有若干国家标准作出了规定,但是这些规定已显得有些陈旧,不能与国际接轨,不适应目前的需要。本文介绍和探讨目前国际较为通用并行之有效的精密度试验及设计。试验时视测量方法的性质和使用要求,以及试验过程中可能产生的弊病,可采用不同的设计,以期所得试验结果在实际工作中是切实可行的。     

提高炭黑着色强度测试精密度的方法

一、概述近年来,轮胎行业对橡胶补强的要求不断提高,炭黑技术指标着色强度也逐渐引入到质量目标要求中。着色强度测试方法GB/T3780.6-2007标准中精密度不高的现状因此体现了出来,其重复性为2.79%,再现性为5.73%,这样的重复性降低了对生产工艺的指导意义,而再现性较大,很容易与用户单位发生质量纠纷,为此提高着色强度测试方法精密度的研讨势在     

层内混杂型机织织物增强复合材料的力学性能(英文)

在很多领域,如汽车,飞机,土木工程及房屋装饰等,随着对复合材料需求的增长,碳纤维已经成为了一种不可或缺的增强材料。这主要归因于其优异的力学性能,如轻质、高硬度、高强度、抗腐蚀、抗疲劳及优异的结构适用性等。黄麻纤维纯天然有着优异的透气性和吸收性。玻璃纤维也是一种重要的纤维而且已经得到了广泛应用。与碳纤维相比,玻璃纤维的力学性能较低而且密度较大,但是同时它也具有低廉的价格。为了充分利用这些纤维的优势,本研究中使用了混杂织物的增强结构,采用碳纤维-玻璃纤维混杂型粗纱布和玻璃纤维-黄麻纤维混杂型粗纱布作为增强结构,以手糊成型的工艺制备了复合材料。对复合材料不同方向的拉伸试验(0°,5°,15°,45°,90°)进行了测试,并使用声发射系统分析了材料的破坏特征。材料的低周疲劳性能也同样进行了分析和研究。     

二维C/(BC_x–SiC)_n复合材料的高温层间剪切性能(英文)

采用双槽口剪切法(double-notched shear,DNS)研究了二维(two dimensional,2D)碳纤维增强碳化硼-碳化硅[2DC/(BCx-SiC)n]复合材料的高温层间剪切性能,用扫描电子显微镜观察断口形貌。结果表明:在25～1200℃范围内,温度对2DC/(BCx-SiC)n复合材料的层间剪切强度有明显影响,在900℃时材料的层间剪切强度最高可达40.0MPa,分别比25℃和1200℃的高约13%和8%,略高于700℃的。此外,C/(BCx-SiC)n的层间剪切强度始终高于C/SiC的强度,且2种材料的层间剪切强度随温度变化规律相似。断口分析表明:层间剪切失效发生在基体内部或基体/纤维界面上,而纤维并没有受到损伤。     

热塑型聚氨酯复合体系力学性能研究

采用压延机，在加工温度不高于１２０°Ｃ的条件下，成功地制备出热塑型聚氨酯弹性体（ＴＰＵ）与高氯酸铵、铝粉及增塑剂邻苯二甲酸二丁酯（ＤＢＰ）等组成的复合胶片，拉伸实验结果指出了所制备的热塑性弹性体复合体系具有良好的力学性能，完全达到或超过推进剂体系的要求指标。     

Mechanical Properties of Thermoplastic Butadiene–Styrene (SBS) and Oxidized Short Carbon Fibre Composites

This work reports on some results of research conducted on composite materials consisting of a butadiene–styrene (SBS) thermoplastic elastomer matrix filled with short carbon fibres previously subjected to oxidative treatment to increase the surface functionality. Scanning electron microscopy confirms the existence of interactions between the matrix and the fibre, which are not observed for commercial fibre fillers and which translate into mechanical strength increments, in terms of the Young’s modulus, tensile and tear strengths for the oxidized fibre composites. The stress–strain curves of the composites show yield point phenomena as strain is applied longitudinally to the main fibre orientation. In oxidized fibre composites the stress and strain coordinates are a function of the degree of oxidation (greater strain for more strongly oxidized fibre) and fibre strength (lower stress for longer treatment times). © 1997 SCI.     

Electrical and Mechanical Properties of Thermoplastic Polyurethane and Polytetrafluoroethylene Powder Composites

To determine the possibility of using polytetrafluoroethylene (PTFE) powder as reinforcing filler in the thermoplastic matrix, the thermoplastic polyurethane (TPU) as the matrix and PTFE powder as reinforcing filler were used to prepare a particulate reinforced composite, in order to determine testing data for electrical and mechanical properties of the composites according to the filler loading in respect to TPU polymer matrix. The TPU and PTFE powder composites were prepared by the milling TPU with 2.5, 5, 7.5, and 10 wt% of PTFE powder in a two roll mill and the milled material is compression moulded to make sheets. From the sheets, the test specimens were made and tested for electrical properties—dielectric strength, dielectric constant, surface, and volume resistivity; fire resistance—rate of burning; mechanical properties—tensile strength and elongation, impact strength, hardness; density and melt flow index. The incorporation of PTFE powder has significantly improved the electrical properties—dielectric strength, dielectric constant, surface and volume resistivity; and fire resistance—rate of burning of thermoplastic polyurethane. However, the tensile strength decreased from 24.91 to 14.71 MPa and tensile elongation increased from 620 to 772 percentage.     

不同预型件工艺对亚麻/聚丙烯热塑性复合材料力学性能的影响

采用交织混编法和包覆纱法加工成型亚麻聚丙烯热塑性预型件及其复合材料,比较了这两种成型方法对预制件及其复合材料的浸渍效果、拉伸性能和剥离性能的影响。结果表明,包覆纱法制备的预型件及其复合材料的浸渍效果较好,孔隙率较低,且力学性能较好,其拉伸强度比交织混编法制备的复合材料拉伸强度提高了46%,剥离强力提高了39%。     

胶粉/POE-g-(MAH-co-St)/POE共混型热塑性弹性体的形态和性能

考察胶粉(WTRP)POE-g-(MAH-co-St)/POE共混型热塑性弹性体的性能和结构以及再加工性.实验结果表明:活化胶粉/POE-g-(MAH-co-St)/POE的比例为70/15/15时,该热塑性弹性体的拉伸强度可以达到9.71 MPa,断裂伸长率达到463.71%.且具有再加工性,可以循环利用.添加POE-g-(MAH-co-St)之后的共混料,界面结合更加紧密,提高了共混料的力学性能.     

剑麻预处理对热塑性淀粉复合材料力学性能及降解性能的影响

采用碱、蒸汽爆破等对剑麻纤维进行预处理,考察了不同预处理方法对剑麻纤维增强热塑性淀粉力学性能及降解性能的影响。结果表明:碱处理能够提高复合材料的力学性能,延长材料降解周期,是制备剑麻纤维增强热塑性淀粉复合材料有效的预处理方法;剑麻纤维增强热塑性淀粉的机理是甘油在淀粉及剑麻纤维之间起到桥梁作用,提高了热塑性淀粉与剑麻纤维的界面结合力,从而提高了复合材料的力学性能。     

短切CF增强TPEE热塑性复合材料的注射成型及力学性能研究

以热塑性聚酯弹性体(TPEE)为基体材料,8 mm短切碳纤维(CF)为增强材料,制备CF/TPEE复合材料。材料通过双螺杆挤出系统混合塑化、挤出造粒后,再经过注塑成型制备成标准拉伸试样,通过力学性能测试及微观结构观察,系统研究了碳纤维含量和等离子表面处理对CF/TPEE复合材料拉伸性能的影响。结果表明,当碳纤维含量为20%时,CF/TPEE复合材料的拉伸强度最大,为39.08 MPa;相比于纯TPEE,其拉伸强度提高了217%;经过等离子表面处理后,拉伸强度进一步提高了5%。结合拉伸后断面的SEM图发现,注塑试样表层碳纤维取向度高,而近中区和中心层取向度相对较低,这是注射CF/TPEE复合材料拉伸性能提高效应不明显的主要原因。     

Effect of Nickel-Cobalt-Zinc Ferrite Filler on Electrical and Mechanical Properties of Thermoplastic Natural Rubber Composites

Thermoplastic natural rubber (TPNR) as polymer matrix was prepared by the melt blending method. Nickel-cobalt-zinc (NiCoZn) ferrite as a filler was prepared by the double-stage sintering method in air. The filler was incorporated in the polymer matrix using a Brabender internal mixer. The filler content was varied from 0 to 30 wt.%. The morphological study of the fractured surface using a scanning electron microscope (SEM) shows the effects of strain. The X-ray diffraction (XRD) indicates the coexistence of both the ferrite and thermoplastic. Electrical properties were studied using a high frequency response analyzer (HFRA) at room temperature (298°K). The results show that resistivity (ρ) decreases, but the dielectric constant increases, with increasing filler content. The resistivity and dielectric constant for all the composites are in the range of 8.9 × 10⁶–9.7 × 10⁵ Ωm and 33–72, respectively. A sharp change in both quantities around 15 wt.% filler content is interpreted as due to the transition from a dispersed system to an attached system. The tensile study shows that the elongation at break point and the tensile strength of the composite at room temperature decrease with increasing filler content. The hardness of the samples decreases with increasing filler content.