BN表面改性对BN/环氧树脂复合材料导热性能的影响

采用十八烷基三甲基溴化铵（OTAB）阳离子表面活性剂对BN微米片进行有机化改性，研究了BN表面改性对BN/环氧树脂复合材料导热性能的影响。当OTAB浓度为0.6 g · L^-1时，BN表面的OTAB吸附量接近饱和。BN表面改性提高了环氧树脂对BN的浸润性，降低了BN的导热系数。SEM观察及黏度测试结果表明：BN表面改性改善了BN/环氧树脂复合材料的界面性能及体系相容性。由于界面热阻的降低，改性BN/环氧树脂复合材料的导热系数高于未改性BN/环氧树脂复合材料，当BN填充量为30%（填料与树脂基体的质量比）时，改性BN/环氧树脂复合材料的导热系数为1.03 W （m · K）^-1，是未改性BN/环氧树脂导热系数（0.48 W （m · K）^-1）的2.15倍。

Effects of BN surface modification on thermal conductivity of BN/epoxy composites

Octadecyltrimethyl ammonium bromide (OTAB) was used as a cationic surfactant to modify micron BN platelets with an organic surface. The effects of BN surface modification on the thermal conductivity of BN/epoxy composites were studied. The adsorption of OTAB on BN surface is close to saturation at OTAB concentration of 0.6 g · L^-1. BN surface modification improves the wettability of epoxy resin on BN surface and decreases the thermal conductivity of BN. SEM and viscosity characterization show that the interfacial and compatible properties of BN/epoxy composites are improved by the surface modification of BN. Due to the decrease in interfacial thermal resistance, the thermal conductivity of the modified BN/epoxy composites is higher than original BN/epoxy composites. When the filler loading is 30% (mass ratio of filler to matrix resin), the thermal conductivity of the modified BN/epoxy composite is 1.03 W(m · K)^-1, 2.15 times of the thermal conductivity (0.48 W(m · K)^-1) of original BN/epoxy composites.