可降解黄麻/PBS复合材料的结构与力学性能

为解决当前环境污染和可持续发展问题,采用模压成型工艺制备可降解黄麻/PBS复合材料,通过拉伸、弯曲性能测试、红外分析和SEM观察,探讨纤维含量和碱处理对材料性能的影响。结果表明:随着纤维含量的增加,复合材料的拉伸强度先增大后减小,在纤维含量为10%时达到最大值,比纯PBS提高了30.1%;拉伸模量、弯曲强度和弯曲模量均随纤维含量的增大而提高,在纤维含量为30%时分别比纯PBS提高了24.2%、185.5%和107.7%。碱处理后黄麻纤维表面杂质被去除,表面部分刻蚀变粗糙,复合材料的综合力学性能得到提高,其中弯曲模量提高显著,比未处理的黄麻复合材料提高了58%。     

黄麻纤维非织造布增强不饱和聚酯树脂复合材料力学性能研究

为了探讨黄麻纤维非织造布/不饱和聚酯树脂复合材料的力学性能,将黄麻纤维通过针刺工艺制备成非织造布,并对其进行碱处理,制备了不同黄麻纤维质量分数的复合材料,测试了复合材料的拉伸弯曲性能,并采用扫描电镜测试了复合材料的断面形态,分析了黄麻纤维针刺非织造布质量分数与碱处理对复合材料拉伸强度与弯曲强度的影响。结果表明:黄麻纤维针刺非织造布对不饱和聚酯树脂的力学性能具有明显的增强效果,且随着黄麻纤维质量分数的增加,复合材料的力学性能先增加后减小,当黄麻纤维/树脂质量比为20/80时,复合材料的拉伸强度和弯曲强度均达到最大,其中碱处理黄麻纤维针刺非织造布增强复合材料的拉伸强度为41.78 MPa,弯曲强度为59.03 MPa;碱处理后黄麻纤维的表面性能得到改善,使得黄麻纤维与聚酯树脂的界面结合情况得到改善,从而提升复合材料的力学性能。     

苎麻纤维碱-尿素改性工艺的研究

以苎麻纤维为试验原料,设计正交试验和单因素试验,探讨苎麻纤维碱-尿素改性工艺中Na OH质量分数、尿素质量分数、试验时间和浴比对纤维弯曲模量的影响。通过对测试数据进行分析,结果显示:正交试验得到碱-尿素改性工艺中的影响因素对纤维弯曲模量的影响显著性不同,其中Na OH质量分数的影响显著性最大,浴比的影响显著性最小。单因素试验得到碱-尿素改性工艺中的影响因素中苎麻纤维弯曲模量的影响规律也有差异,其中纤维的弯曲模量随着Na OH质量分数、尿素质量分数和试验时间的增加而逐渐减小,但是纤维的弯曲模量随着浴比增加却呈现增大的趋势。     

黄麻纤维/ES纤维复合材料制备及力学性能分析

将黄麻纤维与ES纤维通过针刺非织造工艺制备成非织造布,再经过热压工艺制备成黄麻纤维/ES纤维复合材料,分析了黄麻纤维/ES纤维质量比和黄麻纤维碱处理对复合材料力学性能的影响。通过试验发现,复合材料的拉伸强度与弯曲强度都随复合材料中黄麻纤维的质量分数增加而呈现出先增加后减小的趋势;对于黄麻原麻/ES复合板材,比例为15/85、20/80时,其拉伸强度和弯曲强度最大,纵、横向拉伸强度达到33.69、28.43 MPa,纵、横向弯曲强度达到最大值36.28、31.75 MPa;对于黄麻碱处理/ES复合板材,比例为25/75、30/70时,其拉伸强度和弯曲强度最大,纵、横向拉伸强度最大达到41.06、39.47 MPa,其纵、横向弯曲强度达到最大值49.96、40.38 MPa。试验表明,碱处理提高了黄麻纤维和ES纤维之间的相容性,提高了界面结合强度,碱处理后的黄麻纤维增强ES纤维复合材料的力学性能优于未处理前。     

玄武岩纤维增强缝合复合材料力学性能研究

对比研究了基于玄武岩纤维增强的无缝以及缝合复合材料层板的弯曲、拉伸以及II型层间断裂韧性,研究结果表明:缝合有利于复合材料层板的弯曲性能,随着缝合密度的逐渐增加,弯曲强度先增大后减小,弯曲模量逐渐减小;缝合不利于复合材料层板的拉伸性能,随着缝合密度的逐渐增加,拉伸强度先减小后增大,拉伸模量逐渐增大;缝合提高了复合材料层板的层间断裂韧性,G_(IIC)随着缝合密度的增大而增大。     

PES/CF/PET纤维混杂复合材料的力学性能

选用PES纤维作为基体，碳纤维(CF)作为增强体，聚对苯二甲酸乙二醇酯(PET)纤维作为黏合剂，利用特殊的铺层结构制备出一种低密度、易加工、可回收的复合材料。采用正交试验设计研究了PES纤维质量分数、热压温度、压力和时间对复合材料拉伸性能的影响，并对材料的断裂机制进行了分析。结果表明：PES纤维质量分数是影响复合材料拉伸强度的最主要因素，其次是热压时间，热压温度和压力的影响最小；当PES纤维质量分数为55%、热压温度为270℃、压力为25 MPa、时间为50 min时，PES/CF/PET纤维混杂复合材料具有良好的力学性能，拉伸强度达到59.526 MPa,拉伸模量达到1.576 GPa,断裂伸长率达到6.950%;复合材料拉伸断裂机制主要表现为纤维的断裂。     

黄麻纤维毡增强复合材料的力学性能研究

文章对黄麻纤维进行表面处理,并制作纯黄麻纤维以及与碳纤维混杂的针刺毡;采用真空辅助树脂传递模塑法制备黄麻纤维毡增强乙烯基树脂复合材料,并测试其力学性能.结果表明:碱处理和双氧水处理后黄麻纤维表面杂质被去除,复合材料的界面性能得到改善,综合力学性能得到提高;黄麻/碳纤维混杂增强复合材料的拉伸性能提高更为显著,拉伸强度和拉伸模量比未处理纤维毡增强复合材料分别增加了146.2%和43.6%,但其弯曲性能却低于其他两种处理后的黄麻增强复合材料.     

三维玻璃纤维织物增强不饱和树脂的力学性能研究

以不饱和树脂为基体,三维玻璃纤维织物为增强体,采用手糊/模压工艺,制得三维玻璃纤维增强复合材料,并对其力学性能进行了研究。结果表明,当增强材料的质量分数为10%时,复合材料的拉伸强度和弯曲强度分别为89.38MPa和147.45MPa。与二维玻璃纤维织物增强复合材料相比,其拉伸强度和弯曲强度分别提高了37.46%和21.91%,与短纤维增强复合材料相比,其拉伸强度和弯曲强度分别提高了64.30%和35.83%。另外,为进一步改善基体的力学性能,还考察了刚性粒子(碳酸钙)对复合材料的影响。结果表明,碳酸钙能提高复合材料的韧性,且当碳酸钙质量分数达到20%时韧性最佳。     

不同长度和类型粒料混杂制备玻璃纤维增强聚丙烯复合材料

对由不同长度和类型的粒料(长度为3.00 mm的短纤维粒料S3和长度为11.00 mm的长纤维粒料L11)混合制得的玻璃纤维增强聚丙烯复合材料进行拉伸、弯曲、冲击试验,并通过X-ray CT扫描观察复合材料内部的纤维取向,研究玻璃纤维长度和排列对玻璃纤维增强聚丙烯复合材料力学性能的影响。当L11与S3的混合质量比为90%∶10%时,试样的拉伸强度与弯曲强度都略高于L11制备的试样,且冲击强度保持较高的水平,内部的纤维取向也有明显的改善。由此推测,在长纤维粒料中混入少量(如质量分数为10%)短纤维粒料会改善复合材料内部的纤维取向,并对复合材料的强度起到积极作用。。     

竹原纤维/聚氨酯复合材料的力学性能

为使竹原纤维/聚氨酯复合材料得到更好的应用,采用竹原纤维为增强材料,聚氨酯为基体,制备竹原纤维/聚氨酯复合材料,用不同质量分数的NaOH进行处理,并对处理后的竹原纤维复合材料进行拉伸性能和冲击强力先得到更好的应用,本文采用竹原纤维为增强材料,聚氨酯为基体,制备竹原纤维/聚氨酯复合材料,并对不同浓度的NaoH处理和不同质量分数制备的竹原纤维复合材料进行了拉伸性能和冲击强力的测试分析。结果表明：随着NaoH质量分数增加,复合材料的抗拉强度和冲击强力先增大后减小,断裂伸长率逐渐增大;随着竹原纤维质量分数的增加,复合材料的抗拉强度和冲击强力先增加后减小,其断裂伸长率随纤维质量分数的增大而降低。     

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%。     

The effect of hydrophilic (polyvinyl alcohol) fiber content on the flexural behavior of engineered cementitious composites (ECC)

This paper investigates the effect of hydrophilic polyvinyl alcohol (PVA) fiber’s content (1.2–2.0% volume of composite) on the flexural behavior of engineered cementitious composites (ECC) materials. Different parameters of flexural behavior such as strength at first-cracking and post-cracking stages, deflection at ultimate load, toughness indices according to ASTM 1018, flexural modulus, and energy absorption were determined. Test results showed that the flexural strength and flexural modulus of composites significantly increases by increment in fiber content. However, flexural strength of composites varies from 8.5 to 14 MPa depending on amount of PVA fibers. The toughness indices, deflection at max load and energy absorption were decreased by further increase in the fiber content from 1.6 to 2%. It was indicated that there was an indirect relationship between flexural strength and ductility of composite in higher amount of fiber content.     

Polyvinyl Chloride Reinforced with Areca Sheath Fiber Composites—An Experimental Study

ABSTRACT

This research work deals with fibrous composites obtained by using treated and untreated areca sheath (AS) fibers reinforced in polyvinyl chloride (PVC) by injection molding process. Surface treatments of fibers have been carried out to have a better compatibility with PVC matrix. The tensile and flexural strength have been found to increase at the early stage with the increase in treated areca fiber content till optimum (18 wt% of fiber) fiber loading thereafter declines. At optimum fiber loading, the tensile strength, flexural strength and young’s modulus values are 42.38 MPa, 18.22 MPa and 2.38 GPa, respectively, which give maximum values in comparison to other fiber loadings. Thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), biodegradability tests and scanning electron microscopy (SEM) have been used for analysis. The TGA inferred that the thermal stability of the composites increased as compared to neat PVC matrix. Further, the composites exhibit excellent biodegradability property and their biodegradability increases with the increase of areca fiber content. From the properties obtained at optimum fiber loading (18 wt% of fiber), the composite can be suitable for automotive dashboard and door panel applications.     

Lengthwise jute fibre properties variation and its effect on jute–polyester composite

In this study, the jute reeds were equally divided lengthwise from root to tip in three portions namely root, middle and tip. The fibre diameter, fineness, tensile strength and bundle strength of the three portion jute were evaluated and compared. Unidirectional composites containing about 35(wt/wt)% jute fibre by weight were produced in unsaturated polyester resin matrix. The effect of fibre property variation in composite’s mechanical properties was studied. Tensile and flexural properties of composites made from three portions of jute reed were studied. It was observed that tensile and flexural strength of root portion based composites are 44% and 35% higher than tip portion based composites. Tensile and flexural modulus of tip portion based composites is 18% and 17% higher than root portion based composites.     

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.     

碳纤维/聚丙烯/聚乳酸增强复合材料的力学性能

为在不改变碳纤维/聚丙烯(PP)复合材料力学性能前提下,降低复合材料中PP含量以减轻环境降解压力,通过在碳纤维/PP复合材料树脂体系中掺杂可降解的聚乳酸(PLA)形成共混树脂体系,并经热压成型制备碳纤维增强共混树脂复合材料。探究了PLA、PP共混体系质量比对复合材料冲击、弯曲和拉伸性能的影响。结果表明:随着树脂体系中PLA质量分数的增加,复合材料的冲击强度和弯曲强度都呈先降低后升高、再降低的趋势,拉伸强度呈现先升高后降低的趋势;当PLA质量分数为60%时,复合材料的冲击强度和弯曲强度最高,分别为21.8 kJ/m²和112.5 MPa,拉伸强度为37.2 MPa,复合材料的综合物理力学性能最优,与未添加PLA的复合材料的力学性能相近。     

Effect of Chemical Treatment on Thermal,Mechanical and Degradation Behavior of Banana Fiber Reinforced Polymer Composites

ABSTRACT

The current research endeavor, explores the thermal, mechanical, and degradation behavior of alkaline treated banana fibers reinforced polypropylene composites. Composites incorporating BF (20% w: w) treated with NaOH (5% w: v) aqueous solution were developed using extrusion-injection molding processes. After chemical treatment, the tensile, flexural and impact strength of the composite increases by 3.8%, 5.17%, and 11.50%, respectively. Scanning electron microscope (SEM) observations of tested specimens confirm the fiber pull out and fiber fracture as the main reasons for failure of developed composites under tensile and impact loading. The specimens were exposed to two different environments, water immersion and soil burial for 5 weeks for the degradation studies. The degradation behavior of composites was measured in terms of variation in weight and mechanical properties (tensile, flexural, and impact). The maximum degradation in mechanical properties was observed for the composites buried under soil. The composite lost 7.69%, 12.06%, and 3.27% of tensile, flexural, and impact strength, respectively.     

Extraction and Characterization of Calotropis gigantea Bast Fibers as Novel Reinforcement for Composites Materials

The aim of this study is to scrutinize the use of Calotropis gigantea bast fibers as potential reinforcement in polymer composites. The bast fibers were extracted from the Calotropis gigantea plant bark and some of them were treated with alkali (5 wt.%) solution. The chemical composition, physico-chemical structural properties of the untreated and the alkali treated Calotropis bast fibers were studied. The results of chemical composition analysis indicated that alkali treatment removed most of the non-cellulose materials as confirmed by the FTIR analysis. The X-ray diffraction results exhibited that the crystallinity index of the alkali treated fibers increased in comparison with the untreated fibers, which agrees with the results obtained in the mechanical tests. The tensile strength and modulus of the alkali treated fibers were found to be higher whereas the elongation at break was lower than the untreated fibers. Thermal stability of alkali treated fibers was lower than that of the untreated fiber. Scanning electron micrographs showed roughening of the surface of the fiber due to the removal of the surface impurities and non-cellulosic components on alkali treatment.It can be concluded that alkali treatment is an effective method to improve the surface and mechanical properties of Calotropis bast fibers to be used in composite materials.     

异制件用三维编织复合材料的拉伸性能

通过对具有不同减纱结构参数的三维编织复合材料试件做纵向拉伸实验,分析了该类材料的拉伸性能随编织工艺参数的变化规律以及材料的失效形式。结果表明,纤维体积含量相同时,减纱使复合材料的强度有所降低,初始模量变化不大;减纱点缺陷对复合材料拉伸性能影响较小,试件断裂断面位置具有随机性;如出现一段纱线空缺对性能影响较大,试件大都在减纱截面断裂;如必须减纱才能完成制件的外形尺寸,应使减纱点在整个制件内均匀分布,每个截面的减纱数量不超过总数的10%。