低压缩永久变形导电炭黑/硅橡胶复合材料的制备与性能

Preparation and properties of low compression set conductive carbon black/silicone rubber composites

为获得一种低压缩、永久变形及高回弹的导电屏蔽硅橡胶密封材料,以经偶联剂表面处理的炭黑作补强剂及导电填料,乙烯基硅橡胶生胶作基料,制备出一种导电炭黑/硅橡胶复合材料。研究了不同炭黑含量的导电炭黑/硅橡胶复合材料的力学性能、弹性、分散性以及电性能,采用SEM观察了炭黑在硅橡胶基体中的分布形貌,分析了导电炭黑/硅橡胶复合材料的导电机制及屏蔽机制。结果表明:随着炭黑含量的增加,导电炭黑/硅橡胶复合材料的Shore A硬度由31增至70;拉伸强度先由3.31 MPa增至5.28 MPa,而后趋于稳定;拉断伸长率先由198%增至297%,然后再减小至210%;恒定压缩永久变形量先减小后增大,瞬间回弹率逐渐减小;由于"炭黑簇"的形成及导电通路的完善,导电炭黑/硅橡胶复合材料的导电性能及屏蔽效能增强。

In order to obtain a conductive and electromagnetic shielding silicone rubber sealing material with low compression set and high resilience, a kind of conductive carbon black/silicone rubber composite based on methyl vinyl silicone raw rubber were prepared by filling carbon black treated by coupling agent as reinforcing agent and conductive fillers. The mechanical properties, elasticity, dispersity and electrical conductivity of these conductive carbon black/silicone rubber composites with different carbon black contents were investigated. The distribution morphologies of conductive carbon in silicone rubber matrix were characterized by SEM and the conductive and shielding mechanism of conductive carbon black/silicone rubber composites were analyzed. The results show that with the increasing of carbon black content, the Shore A hardness of conductive carbon black/silicone rubber composites increases from 31 to 70, the tensile strength first increases from 3.31 MPa to 5.28 MPa then tends to be steady, the elongation ratio first increases from 198% to 297% then decreases to 210%, while the constant compression set amount decreases first then increases and the instant rebound ratio decreases gradually. The conductive properties and shielding efficiency of conductive carbon black/silicone rubber composites improve promptly when ＂carbon black cluster＂ and the conductive road are established.