碳化硅-线性低密度聚乙烯导热复合材料的制备与性能

Preparation and properties of SiC/LLDPE thermal conductivity composites

用粉末共混-模压成型法制备碳化硅/线性低密度聚乙烯(SiC/LLDPE)导热复合材料,探讨了SiC和偶联剂处理对复合材料导热性能和力学性能的影响。结果表明复合材料的导热系数随SiC用量的增加而增加,当SiC的体积分数为30·4%时,复合材料的导热系数为0·8233W/(m·K),为纯LLDPE的2倍多;拉伸强度则随SiC填充量的增加而显著下降。当SiC填充量为一定值时,表面改性使SiC在LLDPE基体中的分散状态得到改善,拉伸强度和导热性能得到进一步提高,当NDZ-105用量为3%质量分数时,复合材料性能最佳。SiC的加入使LLDPE材料由韧性断裂转变为脆性断裂,SiC的加入影响了LLDPE的熔融温度和结晶度。

The β-sihcon carbide/linear low density polyethylene （SiC/LLDPE） thermal conductivity composites are prepared via the powder mixing-compression moulded method. The effects of content of SiC and NDZ-105 on the mechanical and thermal conductivity properties of composites are investigated. Results reveals that the thermal conductivity property of the composites are improved with the increasing volume fraction of SiC, and the thermal conductivity coefficient λ comes up to 0.8233 W/（m·K） with 30.4% volume fraction of SiC, being over 2 times of that of native LLDPE. However, the tensile strength of composites decreases sharply with the increasing of SiC. For given SiC loading, the surface modification of SiC results in SiC/LLDPE composites＇ significantly enhanced thermal conductivity and mechanical properties, and the properties of composites are optimal with 3 % （wt） of NDZ-105. The fracture of LLDPE changes from ductile fracture to brittle fracture, and SiC has a certain influence on the melting temperature and crystallinity of LLDPE matrix.