高结合丙烯腈含量丁腈橡胶的序列结构、絮凝体系及物理机械性能

Sequence structure,coagulation system and physico-mechanical properties of nitrile rubber with high bound acrylonitrile content

通过低温乳液聚合制备了高结合丙烯腈含量丁腈橡胶(NBR),使用核磁共振氢谱对其序列结构进行了表征,并研究了不同凝聚剂对其凝聚行为和物理机械性能的影响。结果表明,在高结合丙烯腈含量NBR中出现了BAA序列结构,随着结合丙烯腈含量的提高,BAA、BAB和ABA序列结构的含量逐渐增加,而BBB和BBA序列结构含量则逐渐减少;CaCl_(2)和Al2(SO_(4))3的凝聚效果远优于NaCl和H_(2)SO_(4),前二者凝聚效率均达到了约98%;Al2(SO_(4))3能提高NBR的硬度、拉伸强度、定伸应力和扯断伸长率,由其制备的NBR的扯断伸长率为566%。

Because of a large number of strong polar nitrile groups and unsaturated double bonds in molecular chain,nitrile rubber(NBR)had excellent oil resistance,solvent resistance and mechanical properties.Therefore,it was widely used in aerospace,oil exploration,automobile and printing,etc.At present mass fraction of bound acrylonitrile in NBR on the domestic market was generally in the range of from 18%to 40%,and there was a lack of NBR with high bound acrylonitrile content.In this paper,a kind of NBR with high bound acrylonitrile content,of which mass fraction of bound acrylonitrile was more than 40%,was prepared by low-temperature emulsion-polymerization and characterized by proton nuclear magnetic resonance spectroscopy(1H-NMR),and the change of sequence structure with the increase of bound acrylonitrile content was analyzed[1-2].Based on 1H-NMR spectra,it was calculated that mass fraction of bound acrylonitrile of sample a,b,c and d were around 44%,42%,40%and 35%,as shown in Table 1.