镍顺丁硫化胶氧化断裂行为的解析——(Ⅰ)过氧化物硫化胶体系的氧化断裂行为

在热氧老化过程中,用过氧化物硫化的镍顺丁橡胶是主链分子发生断裂。在连续化学松弛时不能用单一的 Maxwell 松弛方程描述,它近似的符合下式σ(?)/σ(0)=A_1e~(-k)_1~t+A_2e~(-k)_2~t由连续与间歇化学松弛曲线的比较表明,该硫化胶是链断裂反应和交联反应同时发生的,且交联反应速度是逐渐增加的。

Analysis of Oxidative Scission Behaviour oF Ni-catalyzed Polybutadiene Vulcanizates (Part Ⅰ)——Oxidative Scission Behaviour of Peroxide Vulcanizate

Peroxide vulcanizate of Ni—catalyzed polybutadiene has C—C crossl-inks.During the oxidative degradation seission reaction occurs onlyalong the main chain at high temperature.According to the Maxwellian decay curve the chemical relaxationapproximately coincides with the following equationσ(t)/σ(0)=e~(-xt)(1)Upon continuous stress relaxation,its modified equation is express-ed asσ(t)/σ(0)=A_1e~(-k)_1~t+A_2e~(-x)_2~t(2)Comparison of the continuous stress relaxation curve with the intermittent one indicates that in the thermo—oxidative process the mainchain scission and crosslinking reaction concur.And the rate of crossl-ink reaction is gradually speeded up in the initiation step.