Study On The Relationship Between Structure And Crystallized Ability Of Polyisoprene

with the development of rubber industry in recent years, natural rubber is widely used in kinds of rubber products. Natural rubber has good properties. But natural rubber is limited by climate and region, so it can not meet the demand of industrial production. However, polyisoprene has the similar chemical composition with natural rubber and similar properties, polyisoprene is a kind of synthetic rubber, it can be made in large scale. polyisoprene is used into tire and other products as a succedaneum of natural rubber, which has a bright future, although polyisoprene has the similar chemical composition with natural rubber, the microstructure of polyisoprene is different with natural rubber, through the study of the relationship between microstructure of polyisoprene and its properties, it can develop the performance of polyisoprene.This paper studied the relationship between the microstructure of polyisoprene and its crystallization, we analysed the spectra of different polyisoprene by13C-NMR, it showed that polyisoprene has kinds of micro-sequence structure, the difference between the microstructure of different polyisoprene was large, further different from natural rubber, especially the content of cisl,4units and different connection types of units. Natural rubber has high content of cisl,4units, units are connected through head-to-tail. However polyisoprene has lower content of cisl,4units and they are connected through head-to-head or tail-to-tail sometimes. Different polyisoprene with different sequence structure has different cry stall inity, polyisoprene with high content of cis1,4units has better crystallized ability, transl,4and3,4units are not helpful to crystallize. This work studied sequence structure and crystallize ability of domestic and oversea polyisoprene, in order to get the relationship between sequence structure and crystallized ability, it can provide basic data and theoretical support.