加速老化条件下乳胶海绵的热老化规律

Thermal aging regularities of latex sponge under accelerated aging conditions

通过测试热氧老化不同时间后乳胶海绵的质量、黄色指数和断裂应力的变化情况,考察了其老化的规律。结果表明,随着老化程度的加深,含天然橡胶质量分数为80%乳胶海绵(80 NR)的质量逐渐减小,颜色越来越黄,断裂应力逐渐增大;含天然橡胶质量分数为20%乳胶海绵(20 NR)的质量和断裂应力在整个老化过程中的变化不大,但颜色也有变黄现象。乳胶海绵在老化过程中主要发生氧化分解反应,导致发生主链断裂和交联,进而引发其质量、色度和强度的变化,其中20 NR中含有大量丁苯橡胶成分,因此相比80 NR其耐老化性能更好。

The aging regularity was investigated through testing the change of mass,yellow index and stress at break of latex sponge after different time of thermal-oxidative aging.The results showed that the mass of sponge containing mass fraction of 80%na-tural rubber(80 NR)decreased gradually,the color was getting yellow and the stress at break increased with increase of aging degree;the mass and stress at break of latex sponge containing mass fraction of 20%natural rubber(20 NR)changed little in the period of aging,but color also turned yellow.The latex sponge mainly undergoed oxidative decomposition reactions during the period of aging,leading to main chain breakage and crosslinking,which resulted in change of its mass,color and strength.Among them,20 NR contained a lot of styrene-butadiene rubber,so its aging resistance was better than that of 80 NR.