Thermal ageing of ethylene propylene copolymer

In order to appreciate the ethylene propylene copolymer service life in electrical materials, we decided to carry out experiments on this material. The ethylene propylene copolymer is used as joints in captors of automatic materials, which are placed in the reactor of nuclear plants. The main stresses applied to this material are temperature, radiation and compression. The most critical parameter during accidental service conditions is temperature: all the electrical equipment inside the reactor must resist from ambient temperature to 156/spl deg/C, but the ethylene propylene copolymer material is not recommended to be used at a constant temperature higher than 150/spl deg/C. That is why we first studied the effect of temperature between 130/spl deg/C and 190/spl deg/C. The main properties we examined were the elongation and the tensile strength at break. The end-point criteria was considered to be 50% as the percentage of the initial value of the elongation at break. The service life of ethylene propylene at high temperatures was estimated from experimental results and the reactions mechanisms were proposed.