The thermal ageing of a silane-crosslinked polyethylene stabilised with 1 wt% of distearyl thiodipropionate (Irganox PS802) was studied in air at three different temperatures: 87 °C, 110 °C, and 130 °C. FTIR spectroscopy and DSC under O₂ were used in a complementary way to monitor the antioxidant (AO) depletion during thermal ageing, but also to detect the polymer oxidation. In particular, at the three ageing temperatures under study, it was observed that the physical loss of AO is the main ageing mechanism and is controlled by AO evaporation. However, the contribution of the AO chemical consumption in the overall kinetics of AO depletion was also estimated. In addition, the temperature dependences of the evaporation constant and the rate constant of the chemical consumption of AO were approximated with the usual Arrhenius law in the temperature range under investigation. Although the corresponding activation energies must be considered with caution, due to the limited amount of data acquired in this study, they were found to be in good agreement with the few results available in the literature.

在三种不同的温度下（空气温度：87°C，110°C和130°C）在空气中研究了用1 wt％的二硬脂基硫代二丙酸酯（Irganox PS802）稳定的硅烷交联聚乙烯的热老化。O ₂下的FTIR光谱和DSC可以互补的方式使用它们来监测热老化过程中抗氧化剂（AO）的消耗，还可以检测聚合物的氧化。特别是，在所研究的三个老化温度下，观察到AO的物理损耗是主要的老化机理，并受AO蒸发控制。但是，还估计了AO化学消耗量对AO消耗的整体动力学的贡献。此外，在研究的温度范围内，AO的蒸发常数和化学消耗的速率常数与温度的关系近似于通常的阿伦尼乌斯定律。尽管必须谨慎考虑相应的活化能，但由于这项研究中获得的数据量有限，