| The synthesis of star-branched polyisobutylene(IB) and star-branched butyl rubber containing low gel were studied. The synthesis were accomplished by the typical cationic polymerizations using DVB as branching agent. The effects of different addition sequences of branching agent and different amount of DVB on synthesis star-branched butyl polymer were investigated. Star-branched butyl polymer containing low gel had been synthesized by controlling the adding amount of DVB and adding as required Macroinitiator St-VDC. Star-branched butyl rubber containing low gel and bimodal distribution have been synthesized that Mn=1.21×10~5g/rnol,MWD=6.10,g=29. Star-branched butyl polymers were characterized by DAWN, GPC, IR,~1H-HMR, TG GPC chromatogram showed bimodal distribution. The performances of star-branched butyl polymer were analysed, in comparison with line-shaped butyl polymers. The mechanism was proposed. |
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