苎麻原长纤维和短切纤维对其复合材料力学性能的影响

选取了不同脱胶状态的苎麻原长纤维和短切纤维作为增强材料,以环氧树脂为基体材料,经树脂传递模塑工艺制成复合材料板,并对其进行力学性能测试。结果表明,在不同脱胶状态下,与苎麻短切纤维增强复合材料板相比,苎麻原长纤维增强复合材料板的拉伸和弯曲性能更为优异,其压缩性能与短切纤维增强复合材料板的压缩性能相近。但受脱胶状态的影响,苎麻原长纤维增强复合材料板的剪切性能则不及苎麻短切纤维复合材料板。     

针刺加固频率对黄麻纤维/聚乳酸短纤复合板性能的影响

为使生物质可降解复合材料在汽车内饰领域替代传统石油基材料，以黄麻纤维(JF)、聚乳酸(PLA)短纤为原料，通过纤网模压成型法制备了黄麻纤维/聚乳酸短纤(JF/PLA)复合板，着重探讨了针刺过程中不同针刺频率对复合板结构及性能的影响。结果表明，当针刺频率为300次/min时，复合板的力学性能达到最大，其纵向拉伸强度、弯曲强度及缺口冲击强度分别为14.54 MPa、33.02 MPa、9.54 kJ/m²。进一步增加针刺频率，纤网中部分黄麻纤维会发生断裂，造成复合板力学性能出现下降。另外，针刺频率的提高使得复合板吸水率与生物降解速率下降，同时复合板的阻燃效果得到改善，有利于JF/PLA复合板在汽车内饰领域的推广应用。     

浸渍工艺对高性能纸基材料摩擦性能的影响

通过碳纤维、短切芳纶纤维和芳纶浆粕作为增强纤维制备高性能摩擦材料原纸,然后用树脂对原纸进行浸渍制造汽车用纸基磨擦材料。研究了树脂种类、含量以及浸渍方式,对耐摩擦材料的孔隙率、摩擦性能和磨损的影响。实验结果显示:双酚A型-硼酚醛树脂作为黏结剂的性能优于酚醛树脂,在树脂含量27%左右,摩擦性能最好,磨损较小。浸渍加入氟橡胶可以提高摩擦材料的摩擦性能。     

对位芳纶沉析/短切纤维及其纸基材料性能的研究

为了解对位芳纶沉析纤维这种新型纤维和短切纤维的特性,并制备出高性能纸基复合材料,本文采用SEM表征了芳纶纤维的表观形貌;通过纤维质量分析仪(Morfi Compact)、保尔筛分仪测定了纤维的形态参数;分别探讨了沉析/短切纤维的处理工艺及配抄比例对纸基材料性能的影响,并利用TGA研究了纸基的热学性能。结果表明:短切纤维呈刚性圆柱状,两端粗细一致,表面光洁均整;沉析纤维呈薄膜褶皱状,形态细小,纤维均一性好,细碎化程度高,有利于纸基材料的匀度和强度;采用沉析纤维的打浆度60SR,短切纤维的分散剂用量0.3%,配抄比例7:3的工艺条件,将获得最佳机械性能和介电性能的芳纶纸基材料;这种纸基材料初始分解温度高达535℃,TG10%为560℃,说明其热学稳定性优异。     

芳纶Ⅲ纸基复合材料的制备与性能研究

以芳纶Ⅲ短切纤维与间位芳纶沉析纤维为原料,使用湿法成形技术,制备芳纶Ⅲ纸基复合材料,研究芳纶Ⅲ短切纤维长度和占比对芳纶Ⅲ纸基复合材料匀度、抗张强度、弹性模量、断裂伸长率、撕裂度的影响规律。结果表明,在芳纶Ⅲ短切纤维长度6 mm,占比50%时,芳纶Ⅲ纸基复合材料的综合力学性能较好,其中抗张强度为2.66 kN/m,弹性模量为3 136 MPa,断裂伸长率为1.78%,撕裂度为2 912 mN。纸基复合材料拉伸断裂面因芳纶Ⅲ短切纤维长度和占比的不同而呈现不同的形状。相比于间位芳纶纸,芳纶Ⅲ纸基复合材料具有更好的高温尺寸稳定性,有望在复合增强领域进一步提升芳纶的应用前景。     

聚间苯二甲酰间苯二胺纸的制备及其性能

采用PMIA短切纤维和沉析纤维为原料来制备PMIA纸,采用扫描电子显微镜和ASAP-2020吸附仪表征了沉析纤维的表面形态,分析了其滤水性能。并研究了沉析纤维的形态、短切纤维的含量和热压温度对PMIA纸力学性能的影响。结果表明:采用沉析纤维B、60%短切纤维含量、280℃热压温度的工艺条件得到的PMIA纸的力学性能最佳。与同类PMIA纸相比,在性能上接近甚至超过进口商品样。     

芳纶复合纸基摩擦材料的初步研究

本文采用高性能芳纶纤维和剑麻纤维为原料制备湿式成型纸基摩擦材料.初步探讨了原纸中两种纤维的配比、剑麻打浆度、芳纶纤维的长度和形态以及作为粘结剂的酚醛树脂的种类和上胶量等对纸基材料的力学性能和摩擦性能的影响,为进一步研究湿式成型纸基摩擦材料奠定基础.     

纸基摩擦材料坯体组分的研究现状

纸基摩擦材料是一种多孔性、吸油、易压缩和回弹性能优异的摩擦材料,纸基摩擦材料坯体的组分对各项性能起着至关重要的作用。重点介绍了增强纤维(天然植物纤维、无机纤维、碳纤维、有机合成纤维、混合纤维)和摩擦性能调节剂(减摩剂、增摩剂、多种调节剂混合)2种坯体组分的研究进展,通过对各种纸基摩擦材料综合性能总结对比,提出采用环境友好、耐高温、摩擦因数稳定、磨损率低的材料和优化各组分结合的方式将成为坯体组分研究的主要方向。     

分层接结三维机织预制体增强酚醛树脂基材料的摩擦性能

为克服短切纤维和二维碳布增强预制体结构强度低的缺点,分别设计并制备了浅交弯联和深交联2种分层接结三维机织碳纤维预制体增强酚醛树脂基复合材料,并以相同复合工艺制备了短切碳纤维增强酚醛树脂基复合材料。测试碳纤维/酚醛树脂复合材料的摩擦性能,并通过观察３ 种复合材料的磨损表面和磨屑的微观形貌,探讨了其摩擦机制。结果表明：短切纤维复合材料的摩擦因数和磨损率最高,深交联的摩擦因数和磨损率最低,浅交弯联的居中。分层接结三维机织结构预制体具有优良的力学性能和整体性,会使复合材料在摩擦过程中减少磨屑与磨损,保持稳定的摩擦因数,从而使复合材料具有良好的摩擦性能。     

纤维对水泥基复合材料性能影响研究进展

为拓宽纤维材料在水泥基复合材料上的应用,促进超高韧性纤维增强水泥基复合材料的发展,对目前国内外纤维性能对水泥基复合材料性能影响的研究进展进行综述。首先,介绍了纤维增强混凝土的种类及增强增韧机制,认为纤维桥接作用可阻止裂纹产生和扩展,显著提高混凝土的拉伸强度和延展性能。其次,分析了混凝土领域常用有机纤维和无机纤维的性能特征;然后对影响纤维增强混凝土性能的因素进行归纳与总结,从混杂纤维、纤维形态、体积分数、纤维排列方向以及纤维粘结性能对复合材料性能的影响关系进行分析。最后,指出纤维增强混凝土研究中亟待解决的问题,并展望了未来纤维增强混凝土的发展趋势。     

聚酰亚胺纤维增强聚二甲基硅氧烷柔性复合膜的热力学性能

针对纤维增强柔性膜在服役过程中的热形变规律和可能出现的热力学问题,以聚酰亚胺(PI)纤维为增强体、聚二甲基硅氧烷(PDMS)为基体通过刮刀涂层的方法制备PI纤维增强PDMS柔性复合膜。利用热重分析仪研究了复合膜的热稳定性能,采用万能材料试验仪和热机械分析仪讨论了取向增强纤维线密度和铺层密度对复合膜力学性能和热膨胀系数的影响;采用COMSOL软件模拟分析了纤维取向增强复合膜的热膨胀变形机制。结果表明,复合膜在300 ℃时质量损失率仅为1.22%,表明其在低于300 ℃的环境中较稳定;随纤维铺层密度和线密度的增大,断裂强度和弹性模量逐渐增大;热膨胀系数逐渐降低,且均呈现负膨胀特点,这说明聚酰亚胺纤维取向增强可有效调节复合膜的尺寸稳定性。模拟与实验结果具有较好一致性,模型可用于预测优化PI纤维增强复合膜的热膨胀系数。     

A Review: Nanomaterials as a Filler in Natural Fiber Reinforced Composites

Composite reinforcement is defined as a technique to improve the engineering characteristics of composite and a fiber reinforced composite (FRC) is a composite material consisting of a polymer matrix imbedded with high-strength fibers, synthetic fibers or natural fibers. Natural fibers have recently become attractive to researchers, engineers, and scientists as an alternative reinforcement for FRCs. Nanocomposite shows considerable applications in different fields because of larger surface area, and greater aspect ratio, with fascinating properties. Being environmentally friendly, applications of nanocomposites offer new technology and business opportunities for several sectors, such as aerospace, automotive, electronics, and biotechnology industries. Hybrid bio-based composites that exploit the synergy between natural fibers in a nanoreinforced bio-based polymer can lead to improved properties along with maintaining environmental appeal. This review article intended to investigate natural fiber/nanofiller-based hybrid composite with specific concern to their physical and mechanical properties.     

Exploring the potential of milkweed stalk in wood plastic manufacture

The physical and mechanical properties of milkweed composites based on different loads of milkweed flour and maleic anhydride grafted polypropylene (MAPP) using polypropylene as matrix are investigated in this study. There levels of milkweed fibers (30, 40, and 50 wt.%), one level of mixed milkweed flour (20:20 wt.% fiber:bark), and two levels of MAPP (4 and 6 wt.%) were used to prepare natural fiber-reinforced composites. Physical and mechanical properties including flexural, tension, impact, and thickness swelling were evaluated according to ASTM standards. The result demonstrated that addition of milkweed flour fluctuates mechanical properties of reinforced composite. However, the optimum load of milkweed flour was different in each test. Generally, 40 wt.% mixed flour composite in comparison with 40 wt.% milkweed composite showed lower mechanical results and higher thickness swelling. MAPP as a coupling agent improved physical and mechanical properties of milkweed-filled composites in most properties. The results of this study depicted positive effects of lignocellulose fibers and coupling gent and also negative effect of bark flour as a function of lower cellulose and higher extractive contents on physical and mechanical properties of milkweed-reinforced composites.     

角蛋白异质和同质复合膜的破坏行为探讨

为了选择适合于角蛋白基复合膜的短纤维状增强体,本文分别对纯膜,和以无机晶须与羊毛原纤增强的异质和同质复合膜的损伤和破坏行为进行分析,并探讨了头端分叉状的原纤对复合膜的增强与增韧作用。结合显微镜照片,对其拉伸曲线进行了分阶段讨论,结果表明：增强体的力学性质和形态特征对复合膜的破坏过程产生了一定的影响,但复合膜仍以基体的力学性能为主,加入增强体的同时也引入了大量启裂点,对复合膜性能起到劣化作用,但合适性能和形态特征的增强体仍可改善复合膜的性能。     

Effect of Curing Temperature on Mechanical Properties of Natural Fiber Reinforced Polymer Composites

Nowadays, growing environmental concerns have led many researchers to work in the area of natural fiber reinforced polymer composites. In this work, jute fiber has been used as reinforcement and epoxy as matrix material to develop partially biodegradable green composite with the help of hand layup followed by compression molding technique. The effect of curing temperature ranging from 80°C to 130°C on different samples was investigated for various mechanical properties. Results obtained from the various tests indicate that with increase in curing temperature, impact strength decreases, but tensile and flexural strength increases and decreases thereafter attaining the maximum value at 100°C between aforementioned temperature range. The trend obtained for mechanical properties is further justified through the study of morphology with scanning electron microscopy, and optimum curing temperature has been suggested.     

玻璃纤维多轴向经编复合材料的制备及拉伸性能研究

以环氧树脂为基体,分别以玻璃纤维多轴向经编针织物和玻璃纤维机织物作为增强材料,通过手糊法制备复合材料,并通过试验对比研究两种复合材料的拉伸性能。结果表明,经编复合材料沿各个轴向的拉伸强度比复合前多轴向经编针织物及机织复合材料的强度均有明显提高,增幅均在50%以上,说明多轴向经编复合材料具有更优异的力学性能。这为进一步扩大玻璃纤维多轴向经编复合材料的应用领域提供了有力证据。     

碱处理对涤纶/光敏树脂复合材料力学性能的影响

针对光敏树脂经3D打印成型后试样力学性能较差问题,采用涤纶长丝增强光敏树脂的方法,使用光固化3D打印设备将涤纶长丝和光敏树脂复合成型制备涤纶增强复合材料。为获得较好的增强效果,对涤纶进行碱处理,研究了碱处理各条件下涤纶的减量率与纤维形貌和力学性能的关系,以及其对复合材料力学性能的影响。结果表明:随着减量率的增加,涤纶的形貌及力学性能改变越明显;当涤纶减量率为16.2%时,纤维表面出现连续纵向沟壑,力学强度下降6%,纤维的增强效果最好;经过改性处理的涤纶增强复合材料的拉伸强度和弯曲强度分别达到78 MPa和471 MPa,相比于未处理的纤维增强复合材料分别提升了66%和336%。     

Thespesia populnea Reinforced Cashew Nut Husk Tannin-Based Polyurethane Composites

Polyurethane composites were prepared by reinforcing raw and silane treated Thespesia populnea fibers in random orientations at different fiber length and loadings with polyurethane. The matrix phase is bio- polyurethane (PU1 and PU2), prepared from tannin extracted from Cashewnut husk with Hexamethylene diisocyanate in the absence and presence of extender. Surface modification was carried out with vinyltriethyl silane as coupling agent. Tensile, compression and moisture absorption properties of the composites were evaluated and fiber properties analysed. Results showed that composites had better mechanical properties compared to the non reinforced matrix. Composites from PU1 had better mechanical properties compared to that of PU2. Tensile and compression strength decreased with increase in fiber content in the matrix. PU1 based composites had less moisture absorption than PU2 based composites and the amount of absorption increased with increase in fiber length. The paper suggests that Thespesia populnea fibers have immense scope as reinforcement in the composite industry.     

废旧橡胶/刨花复合工艺的研究

根据废旧橡胶颗粒特征,用炼塑机将其辊压处理后,加入一定量的偶联剂,研究了废旧橡胶/刨花复合工艺,通过极差分析和方差分析得到优化工艺参数为:橡∶木配比为1∶9,施胶量为10%,热压温度为170℃,热压时间为300s.用以上工艺参数制造的复合板材力学性能优异.