Long-term performance of cables based on chlorosulphonated polyethylene

Cables based on chlorosulphonated polyethylene were aged at different temperatures between 120 and 200 °C and their conditions were assessed by mechanical methods: micro-indenter and tensile testing. Some of the cables were not aged prior to the oven ageing whereas other cables had been exposed to almost 25 years of service at controlled temperatures (30–54 °C) and atmospheres (nitrogen and air). An indenter modulus twice that of the initial value was used as a lifetime criterion; the criterion is based on earlier reported data on similar cables from LOCA tests simulating nuclear power plant failure. The remaining lifetime of the cables exposed to almost 25 years of service was determined by a second-stage ageing at 155 and 170 °C and a comparison with lifetime data obtained for unexposed cable samples. The lifetime data, covering a very broad range of temperatures (40–200 °C), obeyed the Arrhenius law with the following values for the activation energy depending on the surrounding atmosphere: 111±5 (nitrogen) and 96±5 kJ mol −1 (air). Air was found to be a more degrading environment than nitrogen at all the temperatures studied.