多壁碳纳米管／聚乙烯复合材料的制备及其导电行为  

Preparation and Electrical Properties of Multiwalled Carbon Nanotubes Filled High-density Polyethylene Composites

作　　者：李文春[1] 沈烈[1] 孙晋[1] 郑强[1] 

机构地区：[1]浙江大学高分子科学与工程学系,杭州310027

出　　处：《应用化学》2006年第1期64-68,共5页Chinese Journal of Applied Chemistry

基　　金：国家自然科学基金资助重点项目(50133020);国家杰出青年基金(50125312)资助

摘　　要：通过对多壁碳纳米管(MWNTS)／高密度聚乙烯(High density polyethylene,HDPE)复合材料的电阻- 温度特性进行了研究。发现MWNTs填充质量分数为1％-2％时,复合体系呈现渗流行为,表现出优异的导电性。同时体系存在特殊的V形温度系数特性(V-PTC特性),即当MWNTs质量分数超过渗流阈值后,体系的电阻率随温度的升高先下降,出现负温度系数特性(NTC转变),然后才出现通常的正温度系数特性(PTC 转变),且具有很好的循环稳定性。V-PTC这种特性源于基体体积膨胀、MWNTs缠结链松弛以及基体的“退火”效应的协同作用。马来酸酐接枝苯乙烯-(乙烯-丁烯)-苯乙烯共聚物(MA-g-SEBS)的加入,可改善MWNTs 和HDPE之间的相互作用,并可基本上消除V-PTC特性,改善导电性。Multiwalled carbon nanotubes（MWNTs） filled high-density polyethylene（HDPE） composites were prepared by melt blending. Electrical properties, especially the resistivity-temperature characteristics of the composites, were investigated. The results show that the composites filled with MWNTs have a perfect conductivity and the electrical percolation threshold is about 1% -2% （mass fraction）. A special resistivity-temperature characteristic, ＂ V-PTC＂ characteristic, was found, which exhibited that when the mass fraction of MWNTs exceeded the electrial percolation threshold, the resistivity of the composites first decreased （NTC effect） as the temperature increased, while it increased abruptly when the temperature approached melting point（Tm） of the matrix（ PTC effect）. It should be noted that this phenomenon has not been found in polymerbased composites filled with other conductive particles, such as carbon black, graphite, carbon fiber, and so on. This V-PTC characteristic is due to the expanding of the matrix volume and the relaxation of the MWNTs entanglement. Maleic anhydride grafted styrene-（ethylene-co-butylene）-styrene copolymer（MA-g-SEBS） acts as a compatibilizer to MWNTs and HDPE, which improves the interaction between filler and polymer matrix, and thus alrnostly eliminated the V-PTC characteristic through restricting the movement of the filler.

关 键 词：碳纳米管 高密度聚乙烯 渗流阈值 导电行为 V—PTC特性 

分 类 号：O63[理学—高分子化学] TQ327.4[理学—化学]