FTIR Study Of Chain Configuration Transformation Based On Homopolymerization Diene Rubbers During Vulcanization And Thermal-Oxidative Aging

The contents of cis- and trans- in homopolymerization diene rubbers were studied by Fourier Transform infrared spectroscopy (FTIR) in suit measurement, with the aim to discuss the transformation of chain configuration during vulcanization and thermal-oxidative aging. The curing process included isothermal and non-isothermal. The thermal-oxidative aging included different temperature and different time. First of all, the transformation of chain configuration in polybutadiene rubber (BR) during vulcanization and thermal-oxidative aging were studied, which including the curing system, the amount of sulfur, the kind of accelerator, the amount of zinc oxide, the kind and amount of antioxidant. The transformation of chain configuration in natural rubber (NR) during vulcanization was studied, which included the amount of sulfur and zinc oxide. The transformation of chain configuration in polyisoprene rubber (IR) during vulcanization was studied, which included the amount of sulfur and zinc oxide. The effect of vulcanization on transformation of chain configuration in BR showed that: Cis-trans isomerization existed in isothermal and non-isothermal curing process, and during the two curing process, the content of cis-1,4 of BR with sulfur curing system decreased by 5% , but cis-1,4 of BR with peroxide curing system decreased by 2%. The degree of cis-trans isomerization increased during vulcanization with increased amount of sulfur. The degree of cis-trans isomerization with accelerator DM was higher than accelerator NS during non-isothermal curing process, but it was nearly in isothermal curing process. The degree of isomerization reaction that occurred during curing process was reduced with the increased amount of zinc oxide. During isothermal vulcanization the degree of isomerization in BR was reduced with addition of antioxidants, and the degree of isomerization was much lower with antioxidant RD.The effect of thermal-oxidative aging on transformation of chain configuration in BR vulcanization on transformation of chain configuration in BR showedthat:Cis-trans isomerization existed in isothermal and non-isothermal curing process,and during the two curing process,the content of cis^-1,4 of BR with sulfur curingsystem decreased by 5％．but cis^-1．4 ofBR with peroxide curing system decreased by2％The degree of cis-trans isomerization increased during vulcanization withincreased mnount of sulfur The degree of cis-trans isomerization with accelerator DMw-as higher than accelerator NS during non-isothermal curing process,but it w-asnearly in isothermal curing process The degree of isomerization reaction thatoccurred during curing process w-as reduced with the increased mnount of zinc oxideDuring isothermal vulcanization the degree of isomerization in BR w-as reduced withaddition of antioxidants,mad the degree of isomerization w-as much lower withantioxidant RDThe effect of thermal-oxidative aging on transformation of chain configuration in BRvulcaJaizates showed that:1fie isomerization reaction Ot BR vulcanizates was alSOoccurred during thermal-oxidative aging,and the degree of isomerization increasedwith higher thermal-oxidative aging temperature and longer time The degree ofisomerization was increased higher after thermal-oxidative aging with the increasedamount of sulfur．The degree of isomerization reaction that occurred duringthermal-oxidative aging was reduced with the increased amount of zinc oxide BRthat added antioxidaJats had little isomerization reaction during thermal aging The effect of vulcanization on transformation of chain configuration in NR showedthat:The content of cis^-1．4 decreased by 2％during non-isothermal curing process．but it was nearly constant during isothermal curing process,and 965cm。'trans-structure emerged in later curing period,which increased with higher curingtemperature and longer time The more amount of sulfur,the more decreased ofcis^-1．4 content during non-isothermal curing process．and 965cm～trans-structureemerged earlier and more time in advance The more amount of zinc oxide,the lessdecreased of cis^-1,4 content during non-isothermal curing process,and 965cm。。trans-structure increased less with curing The amount of sulfur and zinc oxide hadliRle effect on content ofcis^-1,4 in NR during isothermal curing process The effect of vulcanization on transformation of chain configuration in IR showedthat:The content of cis^-1,4 of IR was constant during isothermal and non-isothermalcuring process 965cm^-1trans-structure existed in IR all the time,which increasedwith higher temperature and longer time The amount of sulfur and zinc oxide hadliRle effect on cis^-1.4 of IR during curing process,but the content of 965cm。。traXIS．StrUCture increased with more amount of sulfur and decreased with more amountofzinc oxide...