丁腈橡胶和丁腈酯橡胶对比研究

对丁腈橡胶和丁腈酯橡胶的物理机械性能和动态力学性能进行对比研究,讨论了分子结构对材料热氧老化和动态力学性能的影响。结果表明,丁腈橡胶和丁腈酯橡胶物理机械性能相当,热氧老化试验后丁腈酯表现出更优异的力学性能。在动态力学性能试验中,腈基极性强于酯基,侧基极性愈强,其相互间作用力愈大,单键内旋转愈困难,链的柔顺性愈差,同时丁腈酯的酯基具有柔性,可起到增塑剂的作用,综合因素导致丁腈酯橡胶在低温下的动态力学性能优于丁腈橡胶。热氧老化后,丁腈橡胶和丁腈酯橡胶交联度进一步提高,分子链之间的相互作用力变大导致剪切模量增大。丁腈橡胶的损耗因子偏大是由于丁腈橡胶有极性较强的侧腈基,链段运动时内摩擦阻力大内耗高,热氧老化后损耗因子进一步提高。

Comparative Study on Properties of NBR and BNBR

The physical mechanical properties and dynamic mechanical properties of NBR and BNBR during thermal-oxidative aging were compared,The effects of molecular structure on thermal-oxidative aging and dynamic mechanical properties were discussed.The results showed that the physical mechanical properties of NBR and BNBR were similar,and BNBR exhibited better mechanical properties after thermal oxidative aging test.In the dynamic mechanical properties test,the polarity of NBR is stronger than BNBR,the interaction force is greater,the rotation of single bond is more difficult,and the flexibility of chain is worse.At the same time,the BNBR has flexibility.The dynamic mechanical properties of BNBR at low temperature are better than that of NBR due to these two factors.The degree of crosslinking of the NBR and BNBR is further improved after thermal aging resulting in an increase in the shear modulus.The larger loss factor of NBR is due to the fact that the NBR has a more polar side nitrile group,The internal friction is further increased and the loss factor is further improved after thermal aging.