A series of star-shaped multi-arm styrene-butadiene copolymers(S-g-SSB-6)were syn-thesized by living anionic polymerization,with n-butyllithium as initiator,styrene and butadiene as monomers,2,2-di(tetra-hydrofuran-2-yl)propane as polar structure regulator and hexachlorodisilane as coupling agent.The molecular weight and its distri-bution,coupling arm number and coupling efficiency of S-g-SSB-6 were characterized by gel permeation chromatogram.The rheological properties of S-g-SSB-6,star-shaped multi-arm styrene-butadiene copolymer with SiCl4 as coupling agent,and linear styrene-butadiene copolymer(L-SSB)were charac-terized by rotational rheometer,and the effects of branched chain length and branched chain flexibility on the rheological properties of S-g-SSB-6 were also investigated.The results showed that the coupling arm numbers of S-g-SSB-6 reached 4.1,and the cou-pling efficiency was greater than 80％.S-g-SSB had lower melt viscosity and better fluid flow than those of L-SSB under the same weight-average molecular weight.When the branching degree was the same,the melt viscosity of S-g-SSB-6 increased with the increase of single arm molecular weight and molecu-lar chain rigidity.
关键词
丁苯共聚物/星形支化/活性负离子聚合/六氯乙硅烷/偶联反应/分子量及其分布
Key words
styrene-butadiene copolymer/star-shaped branch/living anionic polymerization/hexa-chlorodisilane/coupling reaction/molecular weight and its distribution
维普
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