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填料对聚丙烯导热复合材料导电和流变性能的影响 总被引:1,自引:0,他引:1
分别制备了炭黑、碳纳米管、炭黑/碳纳米管简单共混以及炭黑碳纳米管化学键合聚丙烯复合材料,研究了不同体系的导热、导电和流变性能。研究发现,使用炭黑/碳纳米管简单共混或化学键合掺杂的复合材料热导率分别达到0.60W/mk和0.63 W/mk,而使用炭黑或碳纳米管杂化的组分热导率仅仅为0.36 W/mk和0.45 W/mk。掺杂碳纳米管或炭黑/碳纳米管简单共混填料的复合材料体积电阻下降了6个数量级,而掺杂炭黑或炭黑/碳纳米管化学键合填料的复合材料均有较好的绝缘性。掺杂杂化组分后,复合材料均出现了剪切变稀现象,在储能模量与频率曲线上低频区出现"第二平台",但掺杂炭黑/碳纳米管化学键合样品的第二平台极微弱。微观结构发现填料在基体中分散良好,填料间形成了很好的架桥。研究结果表明,简单使用炭黑、碳纳米管掺杂对复合材料的热导率改善不佳,使用炭黑/碳纳米管简单混合虽能大幅提高热导率,但影响复合材料的绝缘性能,而将炭黑/碳纳米管化学键合后可满足制备导热绝缘复合材料的要求。 相似文献
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以经处理过的多壁碳纳米管(MW-CNTs)为导热导电填料、三元乙丙橡胶(EPDM)为基体,采用机械共混法制备了MW-CNTs/EPDM复合材料。研究了碳纳米管填料在低填充量(6%)下对复合材料体积电阻率、热导率、热稳定性及力学性能的影响,并通过扫描电镜观察分析MW-CNTs在复合材料中的分布。结果表明:处理后的MWCNTs在EPDM基质中能形成良好的聚合物填料界面,分散均匀,形成有效的导电导热网链。复合材料的体积电阻率随着MW-CNTs填充量的增加而呈数量级的递减,导热系数随之增加,热稳定性提高,填充后的复合材料具有较好的物理机械性能。 相似文献
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《材料导报》2020,(12)
针对聚合物材料导热性差的问题,为了改善聚合物填充复合材料的导热和吸附等性能,以聚丙烯腈和氮化硼为原料,利用静电纺丝方法制备了聚丙烯腈/氮化硼(PAN/BN)有机无机杂化复合纤维。采用扫描电镜、热分析、红外光谱、X射线衍射仪、激光导热仪和比表面积及孔隙度分析仪对复合纤维进行了结构和性能表征。实验通过改变聚丙烯腈和氮化硼在纺丝溶液中的质量比,研究了纤维中不同氮化硼含量对复合纤维形态、结构和性能的影响。结果表明,通过静电纺丝能够把氮化硼包覆并均匀分散在聚丙烯腈聚合物中,可有效改善聚合物的导热和吸附性能。随着纤维中氮化硼含量的增加,材料的热导率增加,当BN质量分数为54.5%时,纺制得到的PAN/BN杂化复合纤维的热导率最高达到3.977 W/(m·K),比热导率为0.048 W/(m·K)的纯PAN纤维高82.8倍左右。 相似文献
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将叠氮基与碳纳米管(CNT)反应,制备叠氮化碳纳米管(ACNT),用FTIR、XPS等手段证明碳纳米管实现了叠氮化;借助超声波的作用使ACNT均匀分散于单体中,然后用原位聚合方法制备了聚三唑/碳纳米管(PTA/ACNT)复合材料。用透射电镜观察ACNT在基体树脂中的分散状况和复合材料的微观结构,研究了ACNT的添加分数对PTA/ACNT复合材料玻璃化温度(Tg)、热稳定性(Td5)和导热系数(λ)的影响。结果表明:与PTA纯树脂相比,当ACNT添加分数为1.0%(质量分数,下同)时,复合材料的Tg提高了33℃,在氮气中Td5提高了15℃,在空气中Td5提高了8℃;当ACNT添加分数为5.0%时,复合材料30℃的λ提高了45%,150℃的λ提高了30%。 相似文献
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Carbon nanotubes (CNT) exhibit excellent thermal conductivity.Therefore they are potential reinforcements in composites materials for thermal management applications,where high thermal conductivity and low coefficient of thermal expansion (CTE) are required.In the present study,CNT/Cu composites containing CNTs varying from 0 vol.% to 15 vol.% were prepared,and their thermal conductivity behavior was studied in detail.The results indicated that the thermal conductivity of the composites shows no enhancement by the incorporation of CNTs.The presence of interfacial thermal resistance and high level of porosity are the main reasons for this low thermal conductivity.The well dispersed 0-10 vol.% CNTs composites show a very close to the thermal conductivity of Cu.However,the addition of 15 vol.% CNTs results in a rather low thermal conductivity of CNT/Cu composites due to the presence a high level of porosity induced by the formation of CNT clusters.The present paper also claims that a further substantial enhancement in thermal conductivity is only possible if the nanotubes are randomly oriented in the plane or if they are all aligned in one direction,for which the processing of CNTs-aligning in metal matrix should be developed. 相似文献
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Carbon fiber reinforced carbon aerogel composites for thermal insulation prepared by soft reinforcement 总被引:1,自引:0,他引:1
To overcome the brittleness and the pyrolysis shrinkage of carbon aerogels, carbon fiber reinforced composites were prepared by copyrolysis of polyacrylonitrile fiber reinforced resorcinol-formaldehyde aerogel composites (PAN/RFs). The PAN/RFs were obtained by impregnating the PAN fiber felt with RF sol and then supercritical drying. Upon carbonization the PAN fiber shrinks with the RF aerogel, thus reducing the shrinkage differences between the fiber and the aerogel, and results in crack-free carbon fiber reinforced carbon aerogel composites, with a thermal conductivity of 0.073 W/m K at 25 °C in air. Our new method may greatly expand the usage of carbon aerogels in general applications. 相似文献
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碳纳米管添加到聚合物中对其结构和性能都有深远的影响,本文通过浓硝酸对碳纳米管改性后,采用水相沉淀聚合的方法制备了聚丙烯腈/碳纳米管复合材料,同时研究了碳纳米管经过浓硝酸处理后其化学结构的变化;探讨了碳纳米管对聚丙烯腈复合材料热学和结晶性的影响。研究表明,浓硝酸常温处理不仅能除去杂质,还可以在碳纳米管表面引入羧基等含氧基团;加入碳纳米管后,聚丙烯腈的预氧化温度有一定程度的提前,放热量明显降低,同时对聚合物的结晶度也有一定程度的影响。 相似文献
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Qiuhong Zhang Jianwei Liu Ryan Sager Liming Dai Jeffery Baur 《Composites Science and Technology》2009
Growing carbon nanotubes (CNT) on the surface of high performance carbon fibers (CF) provides a means to tailor the thermal, electrical and mechanical properties of the fiber–resin interface of a composite. However, many CNT growth processes require pretreatment of the fiber, deposition of an intermediate layer, or harsh growth conditions which can degrade tensile properties and limit the conduction between the fiber and the nanotubes. In this study, high density multi-wall carbon nanotubes were grown directly on two different polyacrylonitrile (PAN)-based carbon fibers (T650 and IM-7) using thermal Chemical Vapor Deposition (CVD). The influence of CVD growth conditions on the single-fiber tensile properties and CNT morphology was investigated. The mechanical properties of the resultant hybrid fibers were shown to depend on the carbon fiber used, the presence of a sizing (coating), the CNT growth temperature, growth time, and atmospheric conditions within the CVD chamber. The CNT density and alignment morphology was varied with growth temperature and precursor flow rate. Overall, it was concluded that a hybrid fiber with a well-adhered array of dense MWCNTs could be grown on the unsized T650 fiber with no significant degradation in tensile properties. 相似文献
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Carbon nanotube (CNT)/cement composites have been proposed as a multifunctional material for self-sensing and traffic monitoring due to their unique electric conductivity which changes with the application of mechanical load. However, material constituent and environmental factors may significantly affect the potential application of these materials. Therefore, it is necessary to understand an influence of material constituent such as porosity and dispersion of CNT and environmental factor such as moisture on the electrical conductivity of CNT/cement composite. This paper investigates the effect of moisture on the effective electrical conductivity of CNT/cement composites. To prepare the specimens, multi-walled carbon nanotubes (MWCNTs) are well dispersed in cement paste, which is then molded and cured into cubic test specimens. By drying the specimens from the fully saturated state to the fully dry state, the effective electrical conductivity is measured at different moisture contents. As the water in the specimen is replaced by air voids, the electrical conductivity significantly decreases. Different ratios of MWCNTs to cement have been used in this study. Micromechanical models have been used to predict the effective electrical conductivities. A comprehensive model is proposed to take into account the effects of individual material phases on the effective electrical conductivity of CNT/cement composites with moisture effect. 相似文献
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Carbon fiber-reinforced carbon aerogel composites (C/CAs) for thermal insulators were prepared by copyrolysis of resorcinol-formaldehyde (RF) aerogels reinforced by oxidized polyacrylonitrile (PAN) fiber felts. The RF aerogel composites were obtained by impregnating PAN fiber felts with RF sols, then aging, ethanol exchanging, and drying at ambient pressure. Upon carbonization, the PAN fibers shrink with the RF aerogels, thus reducing the difference of shrinkage rates between the fiber reinforcements and the aerogel matrices, and resulting in C/CAs without any obvious cracks. The three point bend strength of the C/CAs is 7.1 ± 1.7 MPa, and the thermal conductivity is 0.328 W m(-1) K(-1) at 300 °C in air. These composites can be used as high-temperature thermal insulators (in inert atmospheres or vacuum) or supports for phase change materials in thermal protection system. 相似文献
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Z. M. Elimat W. T. Hussain A. M. Zihlif 《Journal of Materials Science: Materials in Electronics》2012,23(12):2117-2122
The study deals with thermal, dielectric, and DC electrical properties of polyacrylonitrile (PAN)-based carbon fibers/poly(methyl methacrylate) composites. The polymer composites contain 0, 5, 10, 20 and 30 wt.% PAN-based carbon fibers. The thermal conductivity was studied as a function of filler content and temperature. It was found that the thermal conductivity is enhanced by addition of carbon fibers concentration and temperature. The dielectric properties were determined using impedance measurements. The results showed that the dielectric constant and dielectric loss are decreased with frequency, and increased with both temperature and fibers content. The DC electrical conductivity, temperature coefficient of resistance, and activation energy were studied as a function of fibers concentration in the temperature ranges 30–110?°C. It was found that the composites exhibit negative temperature coefficient of resistivity and enhancement of electrical conductivity with increasing temperature and carbon fibers concentration. The observed increase in the DC conductivity was explained according to the approach of conductive paths and connections between the carbon fibers. 相似文献
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Ke Chu Qingying Wu Chengchang Jia Xuebing Liang Junhui Nie Wenhuai Tian Guosheng Gai Hong Guo 《Composites Science and Technology》2010
A novel particles-compositing method was used for the first time to disperse different contents of multi-walled carbon nanotubes (CNTs) in micron sized copper powders, which were subsequently consolidated into CNT/Cu composites by spark plasma sintering (SPS). Microstructural observations showed that the homogeneous distribution of CNTs and dense composites could be obtained for 0–10 vol.% CNT contents. The CNT clusters were appeared in the powder mixture with 15 vol.% CNTs, which resulted in an insufficient densification of the composites. The effective thermal conductivity of the composites was analyzed both theoretically and experimentally. The addition of CNTs showed no enhancement in overall thermal conductivity of the composites due to the interface thermal resistance associated with the low phase contrast of CNT to copper and the random tube orientation. Besides, the composite containing 15 vol.% CNTs led to a rather low thermal conductivity due possiblely to the combined effect of unfavorable factors induced by the presence of CNT clusters, i.e. large porosity, lower effective conductivity of CNT clusters themselves and reduction of SPS cleaning effect. The CNT/Cu composites may be a promising thermal management material for heat sink applications. 相似文献