中文摘要：

在甲苯溶剂中通过预先接枝在SiO_2粒子上的硅烷偶联剂二次接枝环氧链段的方法,制备了接枝环氧链段的SiO_2粒子。采用不同偶联剂处理方式制备了3种SiO_2添加量为1份的SiO_2/环氧树脂纳米复合材料,对纳米粒子进行了红外光谱（FT-IR）、热重分析（TGA）和透射电镜（TEM）表征,测试了复合材料的热力学性能及介电性能。结果表明：偶联剂可起到桥接作用,将环氧链段接枝到SiO_2粒子上,改善了纳米粒子的团聚现象。接枝后的SiO_2粒子表面与树脂基体有良好的相容性。接枝改性后的SiO_2/环氧树脂复合材料的储能模量大幅提高,冲击强度提高了11.9%,玻璃化转变温度变化不大,SiO_2对复合材料的复介电常数实部和虚部有不同程度的影响。相比不使用偶联剂或直接在复合体系中添加偶联剂的方法,通过偶联剂在SiO_2粒子表面接枝环氧树脂能有效降低复合材料复介电常数的实部和虚部。

英文摘要：

Epoxy group was grafted on the nano-SiO_2 particles in toluene solvent by silane coupling agent, which was grafted on the surface of SiO_2 particles previously. Three SiO_2/epoxy nanocomposites with 1phr of SiO_2 treated by different methods were prepared. The nano-SiO_2 particles were characterized by FTIR, TGA and TEM, and the thermodynamic properties and dielectric properties of the composites were tested. The results show that the coupling agent plays a role of bridge, which could graft epoxy group to the surface of SiO_2 particles and improves the dispersion of nanoparticles. The grafted SiO_2 particles have good compatibility with the resin matrix. The storage modulus of the SiO_2/epoxy nanocomposite after grafting increases obviously, the impact strength increases by 11.9%, while the glass transition temperature changes a little, and the SiO_2 has different effect on the real part and imaginary part of complex permittivity. Compared with the method without coupling agent treatment or adding coupling agent directly in the composite, the method grafting epoxy resin to the surface of SiO_2 particles through coupling agent can effectively reduce the real part and imaginary part of complex permittivity of the epoxy nanocomposites.