The Synthesis Of SIBS Thiblock Copolymer By Living Cationic Polymerzation

In this paper,the controlled cationic polymerization of poly(styrene-b-isobutylene-b-styrene)(SIBS)triblock copolymer was performed by using 5-tert butyl 1,3-dimethoxy benzene(t-Bu-m-DiCuOMe)as novel initiator,and the 1H-NMR,DSC,TG and GPC were used to characterize the product's mechanical property,thermodynamic performance and so on.The initiator 5-tert butyl 1,3-dimethoxy benzene as reactant was synthesized through three steps of reaction.The well-defined SIBS triblock copolymer was synthesized through living cationic polymerization with the t-Bu-m-DiCuOMe/titanium chloride(TiCl4)as the initiating system and mixed solution of hexane and methyl chloride as solvent at-80?.The effects of reaction time,the feeding way of TiCl4 and 2,6-Di tert butyl pyridine(DtBP),the reaction time of the styrene and polyisobutylene segments,the molar ratio of styrene,and the amplification experiment of impact copolymer were investigated.The poly(styrene-b-isobutylene-b-styrene)(SIBS)triblock copolymer was tested by H-NMR,DSC,TG and GPC.The microstructure,molecular weight distribution,mechanical properties and thermal properties of SIBS triblock copolymer were characterized.As result,the predetermined molecular weight and narrow molecular weight distribution(<1.3)of triblock copolymer can be obtained with the t-Bu-m-DiCuOMe/TiC14 as the initiating system,and the better mechanical properties of SIBS triblock copolymer can be obtained through the analysis of thermodynamics.The well thermodynamic performance and relatively intact structure SIBS three block copolymer can be obtained with the mixture of hexane and methyl chloride as the solvent at-80?through the exploring of the polymerization conditions of the initiating system t-Bu-m-DiCuOMe/TiCl4 and adding DtBP as the third component.