对丁腈橡胶(NBR)进行热空气老化,通过溶胀法和核磁法(NMR)测试老化后样品的交联密度,结果发现NBR硫化胶核磁法交联密度随着老化时间的增加而增大;溶胀法交联密度随着老化时间的增加先减小后增大。此外,NBR硫化胶核磁法交联密度随着老化温度的增加而增大;溶胀法交联密度随着老化温度的增加先减小后增大。最后研究了NBR硫化胶力学性能与交联密度间的关系,结果发现NBR硫化胶的100%定伸应力随核磁法交联密度的增大而增大;拉伸强度随核磁法交联密度的增大先增大后降低;断裂伸长率随核磁法交联密度的增大而降低。

The hot air aging test of nitrile rubber (NBR) was carried out.Then the crosslink density of the aged samples was tested by swelling and nuclear magnetic resonance (NMR).It was found that the crosslink density measured by NMR of NBR vulcanizate increased with the increase of aging time.The crosslink density measured by swelling decreased first and then increased with the increasing aging time.Besides,the crosslink density measured by NMR of NBR vulcanizate increased with the raise of aging temperature,the crosslink density measured by swelling decreased first and then increased with the raise of aging temperature.Finally,the relationship between the mechanical properties of NBR vulcanizate and the crosslink density was studied.It was found that the 100% fixed extension stress of NBR vulcanizate escalated with the increase of crosslink density of NMR method.The tensile strength increased first and then decreased with the raise of crosslink density measured by NMR,the elongation at break reduced as the cross-link density measured by NMR increased.