短纤维/ABS树脂复合材料导电导热性能研究

Research on electrical and thermal conductivities of short carbon fiber/ABS resin composite

以沥青基短纤维为填料、ABS树脂为基体,采用热压成型工艺制备了短纤维/ABS树脂复合材料,研究了短纤维在复合材料中的分散形貌及其含量和长度对复合材料导电、导热和抗冲击性能的影响。研究结果表明:短纤维在复合材料中分散较为均匀,可以形成较好的导电和导热网络。复合材料沿垂直热压方向的室温电阻率和热导率随短纤维含量和长度的增加而分别呈降低和升高趋势,其电阻率具有明显的"渗逾"现象,添加0.5mm长的纤维粉的复合材料的导电突变用量约为13wt.%,其电阻率为0.6Ω·m,而填充长度为3mm和6mm短纤维的复合材料的渗逾值约为11wt.%,相应电阻率降低至9.0×10-3Ω·m和1.0×10-3Ω·m。当3mm长短纤维含量为29wt.%时,复合材料的室温热导率为23.3W/m·K,较纯ABS树脂提高了136倍。

The piteh-based short carbon fiber and ABS resin were used as filler and matrix to prepare short carbon fiber/ABS resin composite by a hot press molding method. The dispersed morphology of short carbon fiber in the compos- ites and the effect of the content and length of carbon fibers on the electrical and thermal conductivities and impact resist- ance of the composites were investigated. The results showed that the short carbon fibers uniformly dispersed in the com- posite,which helped the formation of electrically and thermally conductive network. The room temperature electrical resis- tivity and thermal conductivity of the composite sperpendicular to the hot pressing direction were decreased and raised re- spectively with the increasing content and length of short carbon fibers, its electrical resistivity had an obvious ＂percolating＂ phenomenon, the electrically conductive mutation content of the composite filled with fiber powder with a length of 0. 5ram was about 13wt. %, the corresponding electrical resistivity was 0. 6lΩ· m. While the percolation threshold of the composite filled with carbon fibers with a length of 3ram or 6ram carbon was about 11wt. %, the corresponding electrical resistivities de- creased to 9 X 10 aΩ· m and 1 X 10-3 Ω·n. When the content of carbon fiber with 3mm length was 29wt. %, the thermal conduc- tivity of the composite was as high as 23. 3W/m · K,which was 136 times that of pure ABS resin.