Electromagnetic and mechanical properties of carbonyl iron powder-filled methyl vinyl silicone rubber during thermal aging

Rubber-absorbing material patches have been extensively applied in various fields because of its softness, excellent adhesive property, and moldability. However, the material undergoes thermal aging when used in a high-temperature environment for a long time. Therefore, the mechanism through which the properties change with aging must be elucidated. This work mainly aims to analyze the electromagnetic and mechanical properties of such materials during thermal aging. Methyl vinyl silicone rubber (VMQ) was loaded with 45 vol% carbonyl iron powder (CIP) and subjected to accelerate thermal aging. The electromagnetic and mechanical properties were measured with a network analyzer and electronic tensile testing machine, respectively. Results confirmed the increase in the complex dielectric constant, the decrease in the band width of reflection loss (RL) ≤ −10 dB, and the lack of significant change in permeability. The tensile strength, tear strength, and Shore A hardness of CIP/VMQ composite-absorbing materials evidently increased, but the elongation at break sharply decreased after hot air aging at 200°C for 14 days. POLYM. COMPOS., 39:2897–2903, 2018.