Extruded conductive silicone rubber with high compression recovery and good aging-resistance for electromagnetic shielding applications

摘要

Present conductive silicone rubber with carbon blacks has low compression recovery, and is difficult to make long-term electromagnetic shielding products. In order to solve the problem, special hollow-shell carbon blacks were used and then treated by coupling agent to prepare conductive silicone rubber. The compression set of conductive rubber at 100 degrees C for 48 h was only 8.9%, displaying a extremely good recovery. Importantly, the special rubber can be extruded and then continuously vulcanized. Moreover, its electromagnetic shielding effectiveness reached beyond 20 dB at the frequency of 0.01 MHz-10 GHz. After the thermal oxidative aging at 90 and 110 degrees C for 30 days, carbon blacks occurred to aggregate, which gives rise to a drop of tensile property and slight effects on the modulus and hardness. The compression set also increased, but it still maintained a low level after 30 days. There is only little change for the conductivity of silicone rubber and thus its electromagnetic shielding effectiveness still retained beyond 20 dB, showing a good aging resistance. It is believed that our findings may provide an effective solution to fabricate rubber products to sever the electromagnetic protection. POLYM. COMPOS., 40:1078-1086, 2019. (c) 2018 Society of Plastics Engineers