电缆附件用二元复合硅橡胶电气性能及机理分析

Electrical performance and mechanism analysis of binary composite silicone rubber for cable accessories

分子链结构对硅橡胶的电气绝缘性能具有较大影响,本文通过实验与分子模拟相结合的方法,探究不同比例、不同种类的硅橡胶共混对复合硅橡胶电气性能的影响规律及机理。结果表明:苯基/乙烯基共混硅橡胶(PMVQ/MVQ)的电气强度提升明显,苯基硅橡胶质量分数为15%的PMVQ/MVQ复合材料体积电阻率为1.04×10^(16)Ω·cm,电气强度为106.87 kV/mm,与乙烯基硅橡胶相比分别提升了1.77倍和13.22%。三氟丙基/乙烯基共混硅橡胶(FMVQ/MVQ)的介电性能得到改善,三氟丙基硅橡胶质量分数为15%的FMVQ/MVQ复合材料介电常数为3.74,与乙烯基硅橡胶相比提升了40.07%。分子模拟结果表明,苯基/乙烯基共混硅橡胶的自由体积随苯基硅橡胶含量增大而减小,三氟丙基/乙烯基共混硅橡胶的自由体积随三氟丙基硅橡胶含量增大而增大,与复合硅橡胶击穿现象吻合。

The molecular chain structure has great influence on the electrical insulation properties of silicone rubber.In this paper,the regularity and mechanism of the blending of different ratios and types of blended silicone rubber on the electrical properties of composite silicone rubber were explored through a combination of experiments and molecular simulations.The results show that the electric strength of phenyl silicone rubber/vinyl blended silicone rubber(PMVQ/MVQ)improves significantly,when the mass fraction of PMVQ is 15%,the volume resistivity of PMVQ/MVQ composite is 1.04×10^(16)Ω·cm,and the electric strength is 106.87 kV/mm,which increase by 1.77 times and 13.22%than that of the vinyl silicone rubber.The dielectric properties of trifluoropropyl silicone rubber/vinyl blended silicone rubber(FMVQ/MVQ)improves,when the mass fraction of trifluoropropyl silicone rubber is 15%,the dielectric constant of FMVQ/MVQ composite is 3.74,which is 40.07%higher than that of vinyl silicone rubber.Molecular simulation results show that the free volume of PMVQ/MVQ decreases with the increase of phenyl silicone rubber content,and the free volume of FMVQ/MVQ increases with the increase of trifluoropropyl silicone rubber content,which is consistent with the breakdown phenomenon of composite silicone rubber.