偶联剂对 PA6/h-BN 复合材料导热性能的影响及复合材料制备工艺优化

Influence of Coupling Agents on Thermally Conductive Properties of Polyamide 6/Boron Nitride Composites and Optimization for Their Preparation Technology

以硅烷偶联剂(KH550)与钛酸酯偶联剂(TM-P)改性氮化硼(h-BN)为导热填料,聚酰胺6(PA6)为基体,通过熔融共混法制备了导热绝缘复合材料。并通过正交实验研究了h-BN粒径、偶联剂用量和h-BN填充量对复合材料导热性能的综合影响。结果表明,在h-BN体积分数为20%,KH550、TM-P最佳用量分别为2.5%、1%(偶联剂与h-BN质量比)时,TM-P对复合材料热导率的提升效果优于KH550;复合材料的热导率提升率随h-BN添加量的增加呈先增加,然后不变,再减小的趋势;复合材料的屈服强度随h-BN填充量的增加而减小,KH550对复合材料力学性能的改善优于TM-P;TM-P用量为1%,h-BN体积分数为25%,h-BN粒径为10~15μm时复合材料的热导率为2.446 W/(m·K)。

Polyamide 6（PA6）/boron nitride（h-BN）composites with a high thermal conductivity were prepared via melt compounding.A silane coupling agent,KH 550,and a titanate coupling agent,TM-P,were used to enhance the interfacial adhesion between PA6 and h-BN and also improve the thermal conductivity.An orthogonal experiment was conducted to investigate the effects of the particle size of h-BN,the loading of h-BN and the amounts of coupling agents on the thermally conductive performance of composites.The results indicated that the optimum amounts of coupling agent used were 2.5wt% and 1wt% for KH550 and TM-P,respectively,when the loading of h-BN was set to 20vol%.TM-P exhibits a better modification effect than KH 550,thus leading to a higher thermal conductivity.The thermal conductivity of composites showed an increase at first and then began to decline with an increase of h-BN loading,but the yield strength tend to decrease.The composites achieved much better mechanical properties when using TM-P as a coupling agent.An optimum processing condition was obtained as follows：the content of h-BN was set to 25 vol % and the particle size of h-BN was determined as 10-15μm.Under this condition,the composites achieved a thermal conductivity of 2.446 W/（m·K）.