碳纳米管含量对树脂/石墨复合材料性能的影响

采用粉末冶金法制备了碳纳米管增强树脂/石墨复合材料,并研究了碳纳米管含量对复合材料弯曲强度、硬度和导电性能的影响。结果表明:随着碳纳米管的加入,复合材料的弯曲强度显著提高、硬度增加、电阻率下降。在碳纳米管质量分数为1.0%时,复合材料的综合性能最优,弯曲强度达到最大值21.9 MPa,比未添加碳纳米管时提高了近22%;硬度(HS)达到最大值21.7,比未添加碳纳米管时提高了近10%;电阻率达到了最小值450.36μΩ.m,比未添加碳纳米管时降低了近17%。     

碳纳米管增强环氧／石墨复合材料的制备与性能研究

采用粉末冶金法制备了碳纳米管增强环氧／石墨复合材料,并研究了酸洗处理对复合材料弯曲强度、硬度和导电性能的影响。结果表明：与未处理碳纳米管相比,酸处理的碳纳米管增加了环氧／石墨复合材料的弯曲强度和硬度,降低了电阻率。酸处理的碳纳米管增强环氧／石墨复合材料的弯曲强度达到21．9MPa,比未添加碳纳米管时提高了近22％;同时复合材料的硬度达到最大值21．7HS,比未添加碳纳米管时提高了近10％;复合材料的电阻率达到了最小值45036μΩ·cm,比未添加碳纳米管时复合材料的电阻率降低了近17％。     

高性能酚醛树脂/石墨双极板导电复合材料的制备

以酚醛树脂与石墨粉料为原料,通过热模压成形得到一种质子交换膜燃料电池双极板材料.研究了酚醛树脂含量、石墨粒径和固化温度对复合材料导电性能与弯曲强度的影响.结果表明随酚醛树脂含量的增加,导电性能降低,强度升高;随石墨粒径的增大,复合材料的导电性能和弯曲强度呈现先增大后减小的趋势;随固化温度的增加,导电性能出现明显波动,而弯曲强度呈先增大后减小的趋势;酚醛树脂质量分数为15%,石墨颗粒粒径为105 μm,固化温度为240℃时,导电复合材料的电导率和弯曲强度可达142 S/cm,61.6 MPa.     

碳化硅对聚氯乙烯/竹粉复合材料性能影响

为比较碳化硅(SiC)含量对聚氯乙烯(PVC)/竹粉木塑复合材料性能的影响,以竹粉为木质纤维,PVC为基体材料,用挤出成型方法制备了不同含量SiC的PVC/竹粉复合材料,对其力学性能、摩擦磨损性能及蠕变性能测试分析。结果表明：当SiC质量分数为3%时,PVC/SiC/竹粉复合材料拉伸强度和冲击强度性能较好,较未添加SiC的PVC/竹粉复合材料分别高出29.0%,4.2%;SiC质量分数为3%时,摩擦系数、磨损失重率最小分别为0.428 5,0.151%;添加1.5%SiC的PVC/竹粉复合材料弯曲强度最高,为36.6 MPa。蠕变应力值为3.552 8 MPa时,SiC含量对PVC/竹粉木塑复合材料应变影响相近,其中,PVC/竹粉/1.5%SiC复合材料应变值最小;应力值为7.105 6 MPa、10.658 4 MPa时,PVC/竹粉/3.0%SiC复合材料应变值最小。     

新型导电复合材料性能的研究

以石墨与环氧树脂为原料通过模压成型得到一种新型导电复合材料,考察了石墨粒径、环氧树脂含量及固化时间对导电复合材料性能的影响。试验结果表明,石墨粒径的减小有利于复合材料强度的提高;环氧树脂含量的增加使复合材料的强度明显提高,而导电性能却下降;并且探讨了复合材料性能随不同固化时间而变化的情况．得到了最佳固化时间。     

原位聚合法制备PMMA／石墨纳米导电复合材料

本文将MMA(甲基丙烯酸甲酯)单体插入膨胀石墨层间,经过原位聚合,制备出以石墨层片为纳米分散相的导电复合材料.这种新型材料的渗滤阈值很低,质量分数只有0.7%;导电性能优异,当石墨添加量的质量分数为1%时,体积电阻率只有20Ω.Cm.与传统的高分子基导电复合材料相比,还具有力学性能好,易加工以及生产成本低等特点.     

岩土工程用玄武岩纤维复合材料研究及性能评价

为了提高岩土工程的施工质量，以玄武岩纤维布、酚醛树脂、纳米材料Si-Q和固化剂ER-1为主要原料，制备了一种适用于岩土工程的玄武岩纤维复合材料，并对其拉伸性能、弯曲性能和抗老化性能进行了测试。试验结果表明：纳米材料Si-Q的加入量越大，玄武岩纤维复合材料的拉伸强度越大，而弯曲强度则先减小后增大；此外，玄武岩纤维复合材料还具有良好的耐酸碱老化性能，当纳米材料Si-Q的质量分数为5%时，玄武岩纤维复合材料在盐酸溶液中浸泡80 d后的拉伸强度和弯曲强度分别为337 MPa和252 MPa，与浸泡前相比强度保留率分别可以达到76.59%和80.25%，而在氢氧化钠溶液中浸泡80 d后的拉伸强度和弯曲强度分别为405 MPa和299 MPa，与浸泡前相比强度保留率则分别可以达到92.05%和95.22%。玄武岩纤维复合材料的综合性能较好，能够满足岩土工程施工对加固材料性能的要求。     

碳纳米纤维对玻纤增强环氧树脂基复合材料机械及耐磨性能的影响

采用真空辅助喷涂的方法制备了相对于玻纤质量分数1%、3%的碳纳米纤维/玻纤/环氧树脂基复合材料,并对其机械性能、耐固体粒子冲蚀磨损性能与纯环氧树脂(EP)、玻纤增强环氧树脂(FRP)进行了对比研究。结果表明:1%、3%碳纳米纤维的加入使得复合材料的拉伸强度达到72MPa、70MPa,相对于EP分别增加了20%、16.7%,相对于FRP分别降低了32.7%、30.7%;弯曲强度达到150MPa、178MPa,相对于EP分别增加了40.2%,66.4%,相对于FRP分别降低了19.8%、4.8%;侵蚀磨损试验中质量损失相对于FRP分别降低了75%、86.7%,在对复合材料机械强度影响较小的前提下大大提高了复合材料的耐磨损性能。     

玻璃纤维增强尼龙66复合材料的结构与性能

使用双螺杆挤出机,采用共混改性方法制备玻璃纤维(GF)增强尼龙66(PA 66)复合材料(GF-PA 66),并对其结构、热性能和力学性能进行了表征。结果表明:制备的GF质量分数分别为20%,25%,30%的GF-PA 66复合材料的密度均低于1.4 g/cm~3,GF在GF-PA 66复合材料体系中呈现纤维交错复杂的网络结构;GF-PA 66复合材料的起始热降解温度均在320℃以上,具有较好的耐热性;随着GF含量的增加,GF-PA 66复合材料的拉伸强度、弯曲强度、弯曲模量升高,当GF质量分数达到30%时,复合材料的拉伸强度为147.4 MPa,比纯PA 66提高了75%,弯曲强度达到202 MPa,比纯PA 66提高了112%,弯曲模量达到7 783.3 MPa,比纯PA 66提高了175%;随着GF含量的增加,GF-PA 66复合材料的悬臂梁冲击强度先降低后升高,当GF质量分数为30%时,复合材料的悬臂梁冲击强度高于纯PA 66。     

麻纤维增强完全可降解复合材料的制备及性能研究

以亚麻落麻纤维、聚乳酸纤维为原料,采用非织造结合模压成型工艺制备了完全可降解复合材料.研究了增强纤维体积分数及纤维长度对复合材料弯曲、冲击性能的影响,采用扫描电镜(SEM)研究了复合材料中纤维与树脂之间的界面结合状况.结果表明:材料的弯曲、冲击强度均随纤维长度的增加而增大,当纤维长度为72mm时,体积分数为40%的材料具有最好的弯曲性能,纵横向弯曲强度分别为55.15、42.02MPa;体积分数为50%的材料具有最好的冲击性能,纵横向冲击强度分别为19.714、14.012kJ/m2;裁切断口处的SEM表明增强纤维与基体树脂之间存有一定数量的空隙,两相之间的界面结合强度有待进一步改善.     

Preparation of graphite composite bipolar plate for PEMFC

This research studied the preparation of graphite composite using liquid thermosetting plastic such as polyester resin (POE), phenolic modified alkyd resin (PhA) and mixed resin (POE with 10% PhA) as a binder. The morphology, physical, electrical and mechanical properties of the graphite composites were analyzed. The results showed that POE could combine with graphite powder (the 66% wt. saturated of graphite powder) better than PhA and mixed resin and gave higher electrical conductivity (4.52 S/cm). It was also found that epoxy resin could improve the mechanical property of composite plate. The addition of TiO₂ and ZnSt slightly decreased the electrical conductivity and the water absorption. Moreover, it was proposed that TiO₂ could improve the mechanical property. Carbon fiber can increase electrical and mechanical properties and water absorption of the composite with POE as a binder. The mixing of wet-lay mixture with graphite, carbon fiber and POE composite improved the mechanical property and decreased the water absorption.     

Synergistic Effects of Carbon Fillers of Phenolic Resin Based Composite Bipolar Plates on the Performance of PEM Fuel Cell

The most essential and costly component of polymer electrolyte membrane fuel cells is the bipolar plate. The production of suitable composite bipolar plates for polymer electrolyte membrane fuel cell with good mechanical properties and high electrical conductivity is scientifically and technically very challenging. This paper reports the development of composite bipolar plates using exfoliated graphite, carbon black, and graphite powder in resole‐typed phenol formaldehyde. The exfoliated graphite with maximum exfoliated volume of 570 ± 10 mL g⁻¹ used in this study was prepared by microwave irradiation of chemically intercalated natural flake graphite in a few minutes. The composite plates were prepared by varying exfoliated graphite content from 10 to 35 wt.% in phenolic resin along with fixed weight percentage of carbon black (5 wt.%) and graphite powder (3 wt.%) by compression molding. The composite plates with filler weight percentage of 35/5/3/exfoliated graphite/carbon black/graphite powder offer in‐plane and trough‐plane electrical conductivities of 374.42 and 97.32 S cm⁻¹, bulk density 1.58 g cm⁻³, compressive strength 70.43 MPa, flexural strength 61.82 MPa, storage modulus 10.25 GPa, microhardness 73.23 HV and water absorption 0.22%. Further, I–V characteristics notify that exfoliated graphite/carbon black/graphite powder/resin composite bipolar plates in unit fuel cell shows better cell performance compared exfoliated graphite/resin composite bipolar plates. The composite plates own desired mechanical properties with low bulk density, high electrical conductivity, and good thermal stability as per the U.S. department of energy targets at low filler concentration and can be used as bipolar plates for proton exchange membrane fuel cells.     

Effect of filler dispersion on the electrical conductivity and mechanical properties of carbon/polypropylene composites

Conducting carbon/polypropylene composites containing a mixed filler of crystalline natural graphite powder, carbon black, and multiwalled carbon nanotubes have been prepared. The effect of the filler dispersion on the electrical conductivity and mechanical properties has been studied. Keeping the graphite content constant and increasing the ratio of carbon black to nanotubes, the conductivity and the flexural modulus increased linearly at different graphite contents. Graphite aggregates on the cross sections were analyzed by optical microscopy to characterize the dispersion of graphite. The results of the optical microscopy studies showed that the dispersion of graphite is affected by the composition and amount of the nanofiller system. Based on the observations simplified morphological models were set up, that allowed to explain the change in the electrical and mechanical properties of the composites of different compositions. POLYM. COMPOS., 34:1195–1203, 2013. © 2013 Society of Plastics Engineers     

Comparative study on the exfoliated expanded graphite nanosheet‐PES composites prepared via different compounding method

Composites made of polyethersulfone (PES) reinforced with exfoliated graphite nanoplatelets are fabricated by melt mixing, polymer solution, and coating. Coating is an efficient compounding method emphasized in this research, where expanded graphite (EG) and PES powder are premixed in isopropyl alcohol using sonication to disperse the EG by coating individual PES powder particles. The microstructure and property of EG/PES composites were investigated by X‐ray diffraction, scanning electron microscope, thermal gravimetric analysis, differential scanning calorimetric, and electronic tensile tester. The electrical conductivity was confirmed using electrochemical tester. It is found that the coating method is more effective than the polymer solution and directly melt mixing methods widely used, in terms of increasing the electrical conductivity and lowering the percolation threshold of thermoplastic composites, and enhancing the probability that the large platelet morphology of EG can be preserved in the final composite. The research reported here provides an understanding on how the compounding method used during the fabrication of composites is important to achieving the optimal mechanical properties, thermal properties, electrical conductivity, and percolation threshold. This method should have wide applicability to all thermoplastic matrix composite systems. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

高热导率聚丙烯/石墨复合材料的制备与性能

为了提高聚丙烯(PP)的导热性能,扩大其使用范围,采用价格低廉的商用石墨对PP进行改性,利用转矩流变仪制备了PP/石墨导热复合材料。研究了粒径为2μm和20μm的石墨及其复配对复合材料热导率及力学性能的影响。结果表明,复合材料的热导率随着石墨用量的增加而显著增大,20μm石墨填充的复合材料热导率高于2μm石墨填充的复合材料;由于石墨的各向异性,层内热导率远高于层间热导率;将两种粒径的石墨复配,固定石墨总质量分数为40%,当2μm石墨与20μm石墨质量比为1︰5时,复合材料层间和层内热导率达到最大,分别为1.125 W/(m·K)和2.897 W/(m·K),比相同用量下单一2μm石墨填充PP分别提高了121%和61%,比单一20μm石墨填充PP分别提高了3.6%和20%。随石墨用量增加,单一粒径石墨填充的复合材料拉伸强度和弯曲强度呈现先减小后增大的趋势,随复配填料中20μm石墨用量增加,复配填料填充复合材料的力学性能呈下降趋势,但弯曲强度变化不大,拉伸强度也在10 MPa以上。     

Performance of graphite filled composite based on benzoxazine resin

In this study, we aimed to prepare and characterize graphite filled composites based on benzoxazine resin for the bipolar plate in fuel cell. Three kinds of graphite (synthetic graphite, natural graphite, and expanded graphite) were used for the preparation of the graphite filled composites. The composites were prepared by means of the compression molding of mixtures of graphite and benzoxazine resin. The properties of the graphite filled composites based on benzoxazine resin were estimated by mechanical property, gas permeability, and electrical conductivity. As a result, it was found that graphite filled composites based on benzoxazine resin showed good gas impermeability, electrical conductivity and mechanical property compared with those of the graphite filled composites based on the conventional phenolic resin. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Sintering Process and Mechanical Property of MWCNTs/HDPE Bulk Composite

Studies have proved that increasing polymer matrices by carbon nanotubes to form structural reinforcement and electrical conductivity have significantly improved mechanical and electrical properties at very low carbon nanotubes loading. In other words, increasing polymer matrices by carbon nanotubes to form structural reinforcement can reduce friction coefficient and enhance anti-wear property. However, producing traditional MWCNTs in polymeric materix is an extremely complicated process. Using melt-mixing process or in situ polymerization leads to better dispersion effect on composite materials. In this study, therefore, to simplify MWCNTs /HDPE composite process and increase dispersion, powder was used directly to replace pellet to mix and sinter with MWCNTs. The composite bulks with 0, 0.5, 1, 2 and 4% nanotube content by weight was analyzed under SEM to observe nanotubes dispersion. At this rate, a MWCNTs/HDPE composite bulk with uniformly dispersed MWCNTs was achieved, and through the wear bench (Pin-on-Disk), the wear experiment has accomplished. Accordingly, the result suggests the sintered MWCNTs/HDPE composites amplify the hardness and wear-resist property.     

PE-HD复合材料导热性能及力学性能的研究

通过双螺杆挤出机制备了高密度聚乙烯（PE-HD）/石墨/CaCO3增韧母料复合材料,并研究了石墨的表面处理、粒径、含量以及CaCO3增韧母料含量对复合材料导热性能及力学性能的影响。结果表明,偶联剂NDZ201对石墨表面具有较好的处理效果。石墨颗粒直径越小,复合材料的热导率及综合力学性能越高。CaCO3增韧母料能明显提高复合材料的热导率及缺口冲击强度。PE-HD/石墨/增韧母料250B的质量比为45/30/25时,复合材料的热导率可达1.72 W/(m·K),其缺口冲击强度与纯PE-HD相近,拉伸强度和弯曲强度分别比PE-HD提高了52 %和88 %。     

Characterisation of graphite nanoplatelets and the physical properties of graphite nanoplatelet/silicone composites for thermal interface applications

Thermally conducting and highly compliant composites were developed by dispersing graphite nanoplatelets (GNPs) into a silicone matrix by mechanical mixing. X-ray diffraction (XRD) indicates that the average thickness of the GNPs decreased from 60 to 35 nm during mechanical mixing. XRD-texture analysis demonstrated that GNP/silicone composites at 8 wt.% GNPs have a higher degree of basal plane alignment than at 20 wt.%. Differential scanning calorimetry showed that GNPs raised the curing temperature of silicone with no significant effect on the glass transition temperature. The thermal conductivity of the 20 wt.% composites reached 1.909 W/m.K, an 11-fold increase over silicone suggesting an improved dispersion compared to similar composites prepared by dual asymmetric centrifuge mixing. The percolation threshold for electrical conductivity of the composites was at ∼15 wt.%. The compressive modulus of the composite increased to twice that of silicone at 20 wt.%. The corresponding strength decreased by a factor of two compared to silicone and this can be attributed to the weak bonding at the GNP-silicone interface. Overall, these GNP/silicone composites, with a high thermal conductivity, low electrical conductivity and compliant nature are promising materials for use as thermal pads for thick gap filling thermal interface applications.