Changes in mechanical and dielectric properties of silicone rubber induced by severe aging

Sheets of silicone rubber (SiR) were aged under various aging conditions to examine its effects on the mechanical and dielectric properties of SiR. Mainly by analyzing the results obtained by mid-infrared absorption spectroscopy, it has become clear that cross-linked structures with siloxane bonds are formed under all the conditions. This makes SiR hard and then brittle, but it also makes better the dielectric properties apparently. An early stage of degradation in SiR can be detected by EAB and complex electric modulus, which is defined as the reciprocal of complex permittivity. Therefore, EAB and complex electric modulus are useful to monitor the aging status of SiR.