BN/Al_2O_3/碳纤维填充MVQ导热复合材料的制备

以甲基乙烯基硅橡胶(MVQ)为基体,片层氮化硼(BN)、球形Al_2O_3、碳纤维为填料,通过共混的方法制备了导热硅橡胶复合材料。利用热重分析仪(TGA),扫描电子显微镜(SEM),电子拉力试验机以及导热系数仪对复合材料的结构和性能进行了表征。结果表明:复合材料的热导率、热稳定性、力学性能、交联密度随着填料量的增加而增加。填料量达50vol.%时,尤以片层BN对热导率增加的效果突出,热导率从0.168增至1.8W/(m·K);碳纤维对复合材料的力学性能贡献最大,拉伸强度从0.48增加到2.98MPa;片层BN在橡胶基体中以面-面接触的方式均匀分散,更易于形成有效的导热网链。

Preparation of BN/Al2O3/Carbon Fiber Filled MVQ Conductive Composites

Thermal conductive methyl vinyl silicone rubber (MVQ) composites were prepared by blending platelet BN,spherical Al2O3 powder or carbon fiber in the polymer matrix.Structure and properties of the composites were characterized by thermogravimetric analysis (TGA),scanning electron microscope (SEM),electronic tester and thermal conductivity measurement.The results show that the thermal conductivity,thermal stability,mechanical properties and cross linking density of the as-prepared composites enhance with increasing loading content of fillers.Thermal conductivity of the composites improves with the incorporation of platelet BN.The quantitative value increases obviously from 0.168 to 1.8W/(m · K) with 50v％dosage.Loading content of carbon fiber is more advantageous to the improvement of mechanical properties.The tensile strength of composites increases from 0.48 to 2.98MPa.Platelet BN disperses uniformly in the silicone rubber matrix via face-to-face method and more steadily forms effective heat-conductive network.