利用聚多巴胺硅烷双重改性氮化硼提高环氧树脂复合材料热物性

Improvement of Thermophysical Properties of Epoxy Resin Composites by Double Modification of Boron Nitride with Polydopamine Silane

添加高导热无机填料可以有效改善环氧树脂(EP)的低导热性,但高填料含量往往会降低复合材料的力学性能。本研究针对少导热填料含量(小于15%(质量分数,下同))下改性氮化硼/环氧树脂复合材料的综合物性进行研究;利用多巴胺、硅烷偶联剂修饰氮化硼,将得到的改性氮化硼添加到环氧树脂中,分析了不同含量的改性填料复合材料的导热性、热稳定性和力学性能。结果表明,表面改性提高了氮化硼在树脂基质中的分散性和与树脂的相容性;与氮化硼/环氧树脂复合材料相比,改性氮化硼/环氧树脂复合材料导热系数、玻璃化转变温度、热稳定性得到了有效提高。当改性氮化硼含量为15%时,改性氮化硼/环氧树脂复合材料的导热系数为0.63 W/(m·K),为纯环氧树脂导热系数的324%,玻璃化转变温度和热分解温度(T10%)分别提高到132.34℃和379.68℃,相较于纯环氧树脂分别提高了10.44℃和10.2℃。当氮化硼填充物的质量分数为3%时,复合材料的拉伸和弯曲强度分别增加为纯环氧树脂的108%和106%。

Filling epoxy resin with inorganic filler to form composite material can effectively improve the low thermal conductivity of epoxy resin, but high filler content tends to reduce the mechanical properties of composites. Thiswork examined the full set of physical characteristics of modified boron nitride/epoxy resin composites with a negligible amount of thermally conductive fillers (less than 15wt%). The thermal conductivity, thermal stability, and mechanical characteristics of modified filler composites with various contents were examined after boron nitride was modified using dopamine and silane coupling agents and added to epoxy resin. The results show that the surface modification enhances the resin’s compatibility and dispersibility. The thermal conductivity, glass transition temperature, and thermal stability of the boron nitride/epoxy composites have all been significantly enhanced when compared to boron nitride/epoxy composites and modified boron nitride/epoxy composites. The glass transition temperature and thermal decomposition temperature ( T 10% ) are increased to 132.34 ℃ and 379.68 ℃, respectively, which are 10.44 ℃ and 10.2 ℃ higher than pure epoxy when the content of modified boron nitride is 15wt%, increasing the thermal conductivity to 0.63 W/(m·K), which is increased to 324% of that of pure epoxy resin. When the boron nitride filler mass fraction was 3wt%, the composites’ tensile and flexural strengths climbed to 108% and 106% of those of pure epoxy resin, respectively.