稀土异戊橡胶热老化研究

Thermo Oxidative Aging of Isoprene Rubber

对未添加防老剂的稀土异戊橡胶进行了150℃热氧老化,利用GPC和1 H-NMR分别考查了其分子量、分子量分布和化学结构的变化,发现老化初期发生降解反应,分子量逐步下降,分子量分布逐渐变宽,化学结构没有明显的变化;老化后期发生交联反应,但交联反应的程度低于降解反应,有醛类或者羧酸类、端双键类化合物和醇类化合物生成。利用TG对未添加防老剂的稀土异戊橡胶的氮气气氛下的热重动力学进行了考察,结果表明随着失重比例的增加,活化能有所增大。

Isoprene rubber without antioxidant was carried out in 150℃ for the thermal oxygen aging. Molecular weight, molecular weight distribution and changes of chemical structure have been investigated by GPC and 1 H-NMR. It is shows that degradation reaction of isoprene rubber happened but no Significant chemical structure changed at the beginning of ageing, but molecular weight decreased gradually, molecular weight distribution becomes wider. However, in later stage, crosslinking reaction happened, but the extent of the crosslinking reaction is lower than the degradation reaction, and aldehydes, carboxylic acid, olefln and alchole were generated. Thermogravimetric kinetics to isoprene rubbers without antioxidant has been investigated by TG under N2. It suggested that with the increase of proportion of weightlessness, the activation energy increased.