Synergism of radiation and temperature in the degradation of a silicone elastomer

•Applying time-dependent chemical kinetics for determination of synergism in combined radiation plus temperature aging environments.•Use of three carefully selected aging conditions to determine importance of synergism in combined radiation plus temperature environments.•Important synergistic effects found for a silicone elastomer.•Amount of synergism depends on degradation level. A new approach for deriving the importance of synergistic effects for combined radiation (dose rate R) plus temperature (T) environments was recently derived using chemical kinetic principals. It was based on obtaining estimates of the time-dependent kinetic rate constants in the thermal and radiation dominated limits and comparing the sum of these rate constants to the rate constant under combined (R,T) conditions. A simplified variation of this approach is presented and applied to a silicone elastomer. Important synergistic effects are confirmed.