混杂填料填充导热硅橡胶性能研究

Properties of Heat Conductive Silicone Rubber Filled with Hybrid Fillers

以甲基乙烯基硅橡胶为基胶,选用不同粒径氮化硅粒子和碳化硅晶须为填料制备了导热硅橡胶。研究表明:大小粒子以最佳比例进行混合填充时橡胶可获较高热导率,并采用Hasselman模型和等效粒径概念来研究混合粒子体系的热导率;将碳化硅晶须和氮化硅粒子并用,在较低用量下体系呈现较高热导率。此外,随混合填料用量增加橡胶热膨胀系数降低,热稳定性提高。

The heat conductive silicone rubber with vinyl endblocked polymethyisltoxane as basic gum and silicone nitride （Si3N4） of different particle sizes and silicon carbide whisker as fillers was prepared. The results showed that the silicone rubber incorporated with a mixture Si3N4 at a preferable mass ratio exhibited better thermal conductivity compared with the case where filler with a single particle size was used; the Hasselman model and the equivalent particle diameter concept were employed to investigate the thermal conductivity of composites. Furthermore, combined use of Si3N4 particles and SiC whisker gived composites with higher thermal conductivity compared with Si3N4 particle used alone at lower filler volume fraction. In addition, the thermal stability increased with increasing hybrid fillers content, while coefficient of thermal expansion（CTE） decreased.