Useful Lifetime Prediction of Rubber Components Using Accelerated Testing

Rubber material properties, and useful lifetime prediction and evaluation are very important in the design procedure to assure the safety and reliability of rubber components. We have been interested for many years in predicting the lifetimes of rubber materials in oxygen-containing environments using a combination of accelerated aging tests and extrapolation models. In this paper, we investigate the heat aging effects on the material properties, and useful lifetime prediction of ethylene-propylene diene M-class rubber (EPDM), and acrylonitrile-butadiene rubber (NBR) for refrigerator components. The experimental results sssay that the crosslink density changes are varied with compositions of rubber vulcanization, and characteristics of heat aging behaviors of rubber vulcanizates are described well using the activation energy change with aging time. The stress and strain curves were obtained from the results of the simple tension test for specimens. To predict the useful lifetime of EPDM, and NBR, the mechanical property changes were determined under accelerated aging conditions. Rubber was aged at temperatures ranging from 50°C to 100°C for times ranging from 1 to 180 days. We present a general approach for more confidently correlating accelerated aging results with aging under service conditions using the Arrhenius methodology. By using the compression set test, several useful lifetime prediction equations for rubber material are proposed.