碱处理对剑麻纤维增强聚乳酸可降解复合材料性能的影响

以剑麻纤维(SF)和聚乳酸(PLA)为原料,通过注塑成型工艺制备了剑麻纤维增强聚乳酸可降解复合材料。研究了连续碱处理剑麻纤维(CASF)和未改性处理剑麻纤维(USF)在不同含量时对复合材料力学性能、吸水性及可降解性能的影响。结果表明:剑麻纤维的质量分数会显著影响复合材料的力学性能、吸水性和降解性能。相较于未改性处理剑麻纤维(USF),碱处理剑麻纤维(CASF)可以进一步提高复合材料的力学性能,降低复合材料的吸水率,延缓剑麻纤维增强可降解树脂基复合材料的降解速率,且酶降解法相较于土埋法降解能够显著加快复合材料的降解速率。当剑麻纤维含量为20%时,CASF/PLA复合材料的拉伸强度、弯曲强度和弯曲模量相较于纯PLA和USF/PLA分别提高了32.71%、10.08%;19.63%、12.11%;97.33%、12.40%;其冲击强度相较于纯PLA提高了71.19%。     

聚烯烃弹性体对剑麻纤维增强聚丙烯复合材料性能的影响

为提高剑麻(SF)增强聚丙烯(PP)复合材料的韧性,分别采取乙烯-辛烯共聚物(POE)和马来酸酐接枝POE(POE-g-MAH)二种弹性体对其进行增韧改性;研究了弹性体和纤维用量的变化对SF/PP/弹性体三元复合体系力学性能的影响及其内在原因。结果表明:POE和POE-g-MAH对剑麻增强聚丙烯复合材料均有良好的增韧效果;仅从增韧效果而言,在弹性体用量较低阶段POE优于POE-g-MAH,但当弹性体增至30%以后,POE-g-MAH则好于POE;在拉伸强度、拉伸模量、弯曲强度及弯曲模量方面,POE-g-MAH均比POE效果更好。     

剑麻纤维增强聚乳酸可降解复合材料力学性能

采用正交实验的方法,以纤维长径比、纤维含量和纤维的处理方式为因素,以剑麻纤维增强聚乳酸可降解复合材料的力学性能包括拉伸强度、拉伸模量、弯曲强度、弯曲模量和冲击强度为指标,运用极差和方差分析方法,探讨复合材料力学性能影响因素的敏感性,得到复合材料力学性能最佳的优化方案.     

剑麻纤维增强聚丙烯复合材料的制备与性能研究

采用动态保压注塑成型技术(DPIM),通过在熔融共混体系中施加往复的剪切应力以改善剑麻纤维(SF)与聚丙烯(PP)复合材料的结构与性能。力学性能测试表明:动态保压获得的样品,拉伸强度与模量获得大幅度提高,但样品冲击性能有所下降。当剑麻纤维质量分数为30%时,动态复合材料的拉伸强度提高了23%。DSC结果表明:由于剑麻纤维充当了结晶成核点的作用,使得复合物的结晶温度提高。     

氧化聚乙烯蜡对聚丙烯/剑麻纤维复合材料力学性能的影响

采用熔融共混与注塑成型的方法制备了聚丙烯/氧化聚乙烯蜡/剑麻纤维(PP/OPE/SF)复合材料,研究了氧化聚乙烯蜡(OPE)对复合材料力学性能的影响.结果表明,OPE显著提高了复合材料的冲击强度,适当添加量的OPE增强了PP/SF的界面键合,提高了复合材料的拉伸强度和拉伸模量.     

PBS/剑麻复合材料制备与性能研究

利用蒸汽爆破预处理剑麻纤维(SESF)作为增强体,通过模压成型制备聚丁二酸丁二醇酯(PBS)/SESF复合材料,研究了SESF质量分数对复合材料力学性能的影响。对比了在剑麻纤维质量分数为30%的条件下,和未经预处理的2种剑麻纤维制得的复合材料的力学性能,并通过扫描电镜(SEM)对试样进行观察分析。结果表明,随着SESF质量分数的增加,复合材料的拉伸强度先增大后减小,在SESF质量分数为30%时达到最大值,比纯PBS的提高了15.5%;弯曲强度和弯曲模量均随剑麻纤维质量分数的增大而提高,其中弯曲强度在SESF质量分数为30%时的比纯PBS的提高了132.5%;断裂伸长率和冲击强度随着SESF质量分数的增加而降低。     

剑麻/FRP废渣/UP复合材料制备及性能研究

采用硅烷偶联剂KH-550和KH-570分别对纤维增强复合材料(FRP)废渣进行表面处理。制备了剑麻纤维/FRP废渣增强不饱和聚酯树脂复合材料。研究了FRP废渣的表面处理方式、FRP废渣含量和剑麻纤维含量对复合材料力学性能、吸水性和热性能等影响。结果表明,经过偶联剂处理的复合材料的力学性能和热稳定性均增强。当FRP废渣质量分数为30.0%,剑麻纤维质量分数为10.0%时,经KH-570处理复合材料的拉伸强度、弯曲强度和冲击强度分别提高22.8%,21.4%和19.2%。FRP废渣经过偶联剂处理后,复合材料的吸水性降低。     

黄麻纤维增强聚丙烯的力学性能

本文讨论了注塑成型黄麻纤维增强聚丙烯的制备方法和力学性能.将纤维重量含量分别为10%、20%和30%的复合材料进行比较,分析纤维含量对复合材料拉伸、弯曲和冲击性能的影响;将纤维分别切成约3mm、5mm和10mm长制成复合材料进行比较,分析纤维长度对复合材料拉伸、弯曲和冲击性能的影响.掺入黄麻纤维能使聚丙烯的拉伸和弯曲性能提高,但使其冲击强度降低;随纤维含量的增加或纤维长度的增加,复合材料的强度和模量是递增的,而冲击强度是递减的.     

玻纤增强聚苯硫醚复合材料的增韧研究

针对玻纤增强聚苯硫醚材料韧性差的问题，对聚苯硫醚傲璃纤维复合体系的增韧进行了研究，考察了玻纤、改性聚合物、有机超细粒子对复合材料力学性能的影响。采用基体增韧（预增韧）与有机超细粒子增韧技术，在保持复合材料拉伸强度和模量的同时，较大地提高了冲击强度，获得了综合力学性能优异的纤维增强聚苯硫醚材料。     

表面处理对剑麻纤维布/不饱和树脂材料性能影响

采用碱、高锰酸钾及热对剑麻纤维布进行了表面处理,并由真空辅助树脂传递模塑成型(VARTM)工艺制备了剑麻纤维布增强不饱和聚酯树脂复合材料。通过对复合材料的力学性能及吸水性的测试,研究了不同剑麻纤维布表面处理对其不饱和聚酯树脂复合材料性能的影响。结果表明:经过碱处理,复合材料的拉伸、弯曲,冲击强度提高最大,可分别提高26.5%,16.5%和22.6%,吸水率降低了47.5%。对剑麻纤维布进行表面处理可使复合材料的界面性能得到改善,力学性能提高,吸水性降低。     

A study of the mechanical properties of randomly oriented short banana and sisal hybrid fiber reinforced polyester composites

The mechanical performance of short randomly oriented banana and sisal hybrid fiber reinforced polyester composites was investigated with reference to the relative volume fraction of the two fibers at a constant total fiber loading of 0.40 volume fraction (V_f), keeping banana as the skin material and sisal as the core material. A positive hybrid effect is observed in the flexural strength and flexural modulus of the hybrid composites. The tensile strength of the composites showed a positive hybrid effect when the relative volume fraction of the two fibers was varied, and maximum tensile strength was found to be in the hybrid composite having a ratio of banana and sisal 4 : 1. The impact strength of the composites was increased with increasing volume fraction of sisal. However, a negative hybrid effect is observed when the impact strength of the composites is considered. Keeping the relative volume fraction of the two fibers constant, that is, banana : sisal = 0.32 : 0.08 (i.e., 4 : 1), the fiber loading was optimized and different layering patterns were investigated. The impact strength of the composites was increased with fiber loading. Tensile and flexural properties were found to be better at 0.40 V_f. In the case of different layering patterns, the highest flexural strength was observed for the bilayer composites. Compared to other composites, the tensile properties were slightly higher for the composite having banana as the skin material and sisal as the core material. Scanning electron micrographs of the tensile and impact fracture surfaces of the hybrid composites having volume fraction 0.20 and 0.40 V_f were studied. The experimental tensile strength and tensile modulus of hybrid composites were compared with those of theoretical predictions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1699–1709, 2005     

Morphology and mechanical properties of unidirectional sisal– epoxy composites

Plant fibers are of increasing interest for use in composite materials. They are renewable resources and waste management is easier than with glass fibers. In the present study, longitudinal stiffness and strength as well as morphology of unidirectional sisal–epoxy composites manufactured by resin transfer molding (RTM) were studied. Horseshoe‐shaped sisal fiber bundles (technical fibers) were nonuniformly distributed in the matrix. In contrast to many wood composites, lumen was not filled by polymer matrix. Technical sisal fibers showed higher effective modulus when included in the composite material than in the technical fiber test (40 GPa as compared with 24 GPa). In contrast, the effective technical fiber strength in the composites was estimated to be around 400 MPa in comparison with a measured technical fiber tensile strength of 550 MPa. Reasons for these phenomena are discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2358–2365, 2002     

Development and physico‐mechanical behavior of LDPE–sisal prepreg‐based composites

Low‐density polyethylene (LDPE)‐coated sisal fiber prepreg was prepared by using solution coating process. These coated fiber prepregs were consolidated to make composites having different weight fraction of sisal fibers in a hot compression‐molding machine. This experimental study reveals that higher loading of sisal fiber up to 57wt% in LDPE–sisal composites is possible by this technique. Mechanical and abrasive wear characteristics of these composites were determined. The tensile strength of composites increased with the increase in sisal fiber concentration. Coating thickness of LDPE was varied by changing the viscosity of LDPE–xylene solution that manifested to different weight fraction of fiber in sisal–LDPE composites. Mechanical, dynamic mechanical, and abrasive wear characteristics of these composites were determined. The tensile strength and modulus of sisal composites reached to 17.4 and 265 MPa, respectively, as compared to 7.1 and 33MPa of LDPE. Storage modulus of sisal composites LD57 reached to 2.7 × 10⁹ MPa at 40°C as compared to 8.1 × 10⁸ MPa of LDPE. Abrasive wear properties of LDPE and its composites were determined under multi‐pass mode; pure LDPE showed minimum specific wear rate. The specific wear rate of composites decreased with the sliding distance. Increase of coated sisal fiber content increased the specific wear rate at all the sliding distances, which has been explained on the basis of worn surface microstructures observed by using SEM. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

剑麻纤维增强聚丙烯复合材料的制备及性能研究

制备了剑麻纤维增强聚丙烯（PP）复合材料,考察了纤维含量及马来酸酐接枝PP（MPP）增容剂对复合材料孔隙率及力学性能的影响,并采用修正的数学模型分别对复合材料的拉伸强度和拉伸弹性模量进行预测。结果表明,随着纤维含量的增加,复合材料的孔隙率先增大后减小,纤维质量分数为30％时孔隙率达到最大值。未添加MPP增容剂时,复合材料的拉伸及弯曲性能在纤维质量分数小于30％时变化幅度较小,40％时则有较大幅度提高;冲击强度随着纤维含量增加而提高。当添加MPP增容剂时,复合材料的力学性能随纤维含量的增加而提高。拉伸性能的预测结果与实测结果比较一致。     

Relationship between processing and properties of biodegradable composites based on PCL/starch matrix and sisal fibers

Biocomposites were produced using polycaprolactone and starch as matrix, and sisal fibers as reinforcement. The matrix is a biodegradable commercial product called MaterBi‐Z, which is based on a polycaprolactone and starch system. The relationship between processing conditions and properties is reported. An alkaline treatment was performed in order to improve the adhesion and the compatibility of the fiber with the matrix. The effect of the treatment on the tensile properties and morphology was determined. Fiber content enhances the tensile properties of the biodegradable composite. The experimentally observed tensile properties (modulus and tensile strength) of short sisal fiber reinforced MaterBi‐Z matrix composites with different fiber loading are compared with the existing theories of reinforcement. SEM photomicrographs of the fractured composite surfaces are also analyzed.     

POE和mPE增韧木塑复合材料的研究

采用废木粉填充高密度聚乙烯制备木塑复合材料,采用茂金属聚乙烯(mPE)和乙烯-辛烯共聚物(POE)对复合材料进行增韧,并阐述了它们的增韧机理,讨论了增韧剂用量对复合材料的力学性能如拉伸强度、弯曲强度、弯曲模量、冲击强度和硬度的影响,综合评价了两种冲击改性剂的增韧效果。研究结果表明:两者对高密度聚乙烯基木塑复合材料均有良好的增韧效果。单就增韧效果而言,POE优于mPE,但在其他性能如拉伸强度、弯曲强度、弯曲模量、硬度以及耐热性等方面,mPE明显优于POE。     

剑麻纤维/长玻纤混杂增强PP复合材料的力学性能研究

采用剑麻纤维(SF)和长玻璃纤维(LGF)混杂增强聚丙烯(PP)复合材料,考察了SF/LGF的比例和含量对PP复合材料力学性能的影响。结果表明:SF/LGF在聚丙烯树脂基体中呈交叉网状分布,这有利于提高复合材料的冲击强度、弯曲模量、拉伸强度和软化点。在SF/LGF质量比为2 2∶,二者总质量分数为30%时,SF/LGF混杂增强PP复合材料的综合力学性能较好。     

Newspaper-reinforced plastic composite laminates: Mechanical and water uptake characteristics

Several useful composite materials have been developed with natural fiber and plastic matrices, and their commercial viability has been established in terms of adding value to abundant and cheap natural resources. The Macromolecular Research Centre, Jabalpur, India, has recently developed composite from waste newspaper reinforced with plastic material using a prepreg technique wherein the matrix resin consists of resol type phenolic resin (PR) and bifunctional epoxy resin (EP) condensate. Laminates of newspaper and PR-EP condensate were prepared by hot press molding, and the newspaper weight fraction in these composites was varied from 0.30 to 0.65. The mechanical properties of five selected newspaper (PR-EP) condensate composites are reported for parameters such as ultimate tensile strength, elongation, tensile modulus, flexural strength and modulus, and heat deflection temperature (HDT). The water uptake behavior of these composites was examined by constructing water absorption isotherms, and the water diffusion coefficient and water absorption (24 h soak test) were determined. The specific tensile and flexural strengths and modulus properties of newspaper-(PR-EP) condensate composites are found comparable with one prepared elsewhere from recyclable newspaper-reinforced polypropylene thermoplastics.     

环氧树脂/短切碳纤维复合材料性能研究

制备出了短切碳纤维增强TDE-85环氧树脂复合材料,研究了碳纤维的含量对复合材料力学性能和耐热性能的影响。结果表明,碳纤维的加入有利于复合材料力学性能和耐热性能的提高,并在碳纤维含量为0.25%时,复合材料的拉伸强度、冲击韧性、弯曲强度和弯曲模量达到最大,分别提高了29.33%、25.31%、30.28%和68.93%。此外,对复合材料的弯曲断裂面进行了微观形貌分析,结果表明一定量的碳纤维可以较好地分散在树脂基体中,同时,碳纤维原丝和树脂基体的界面结合比较弱,主要依赖于两相之间的物理嵌合。