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

A kind of nitrile rubber (NBR) with high bound acrylonitrile content was prepared by low-temperature emulsion-polymerization and the sequence structure of the polymer was characterized by proton nuclear magnetic resonance spectroscopy, and the effects of different coagulants on the coagulation behavior and physico-mechanical properties of the polymer were studied. The results showed that the BAA sequence structure appeared in NBR with high bound acrylonitrile content, and the content of BAA, BAB, and ABA sequence structures increased gradually and that of BBB and BBA sequence structures decreased gradually with the increase in bound acrylonitrile content; the coagulation efficiency of CaCl2 and Al2(SO4)3 was much higher than those of NaCl and H2SO4, and the coagulation efficiency of the first two both reached about 98%; Al2(SO4)3 could improve the hardness, tensile strength, modulus, and elongation at break of NBR, and the elongation at break of NBR prepared from Al2(SO4)3 was 566%.