结合丙烯腈量对丁腈橡胶/炭黑硫化胶热降解性能的影响

Effects of bound acrylonitrile content on thermal degradation behavior of nitrile rubber/carbon black vulcanizates

采用热失重分析法和差示扫描量热法研究了结合丙烯腈量对丁腈橡胶/炭黑硫化胶热降解性能及热降解活化能的影响。结果表明,在降解反应初期首先发生交联环化反应,然后发生断链降解反应。交联反应放出的热量随结合丙烯腈量的增加而降低,最大放热峰温受结合丙烯腈量的影响不大。断链降解过程分为2个阶段,分别受结合丙烯腈量和丁二烯单元含量的影响。初期断链降解受腈基含量影响较大,腈基起到催化和加速降解的作用;430℃以上的失重行为与丁二烯单元的含量有关;494℃以上的降解受丁腈橡胶成炭性质的影响。不同结合丙烯腈量的丁腈橡胶/炭黑硫化胶的降解活化能趋近。

The effects of bound acrylonitrile con- tent on the thermal degradation behavior and degra- dation activation energy of nitrile rubber/carbon black vuleanizates were investigated by thermogravi- metric analysis and differentialscanning calorimetry. The results showed that crosslinking and eyclization reaction occurred in initial degradation firstly, and then chain-breaking reaction happened. The heat re- leased by crosslinking reaction decreased with in- creasing bound acrylonitrile content, and exothermal peak temperature was not affected evidently. The chain-breaking degradation process could be divided into two stages, and both of them were affected by the contents of bound acrylonitrile and butadieneunit respectively. The bound acrylonitrile contents had a great effect on chain-breaking in the initial stage due to its catalysis and acceleration; above 430 % , the mass loss should be attributed to butadi- ene unit content; and over 494 ~C , the degradation behavior was controlled by the carbonization of ni- trile rubber dominantly. The nitrile rubber/carbon black vulcanizates with different bound acrylonitrile contents had similar degradation activation energy.