镍顺丁硫化胶氧化断裂行为的解析——(Ⅲ)普通硫化体系的氧化断裂行为

Analysis of Oxidative Scission Behaviour for Ni-Catalyzed Polybutadiene Vulcanizates Part C——Oxidative Scission Behaviour of Conventional System Vulcanizates

在热氧老化过程中,普通硫化体系的镍顺丁胶是主链断裂、交联键断裂和交换链反应同时存在的复杂行为,可认为在初期阶段交联键断裂与交换链反应比主链断裂优先。连续与间歇化学松弛曲线表明断裂过程伴随交联反应产生,而且在应力作用下多硫交联键断裂并发生重排后,交联反应速度加快。

The conventional accelerator—sulphur vulcanizate—has a high proport-ion of polysulfide crosslinks.During thermol-oxidative aging seission the process is very complexbehaviour in which the main chains and the crosslink cleavages and S-Sbond interchange reactions occur simultaneously.It is considered thatthe crosslink eleavage and interchange reaction have advantange over themain chain cleavage in the early stage.Comparison of the continuous chemistry relaxation curvc with theintermittent one indicates that the chain scission and the crosslink reae-tion concur,and that the rate of crosslink reaction is increased after thecleavange of polysulfidc erosslinks and rearrangement of crosslinks.