Study On Polymerization Of Butadiene With Cobalt Catalyst System

Polybutadiene was prepared with supported Co-Al(i-Bu)₃-CS₂ catalysts. Theeffect of monomer ratios and another conditions of polymerization were discussed indetail. With Co-Al-CS₂ addition orders inner-complexation, the conversion of thepolybutadiene at 10℃was 99%. ¹³C-NMR analysis of the polymer indicated a1, 2-linkage contents of 98% and a syndiotactic of 99%; As determined by X-ray, thecrystallinity of polymer reaches about 75%. The melting point reaches about200℃. By adding quartus components of acetonitrile and H₂O, content of 1, 2-linkage,crystallinity and melting point were not varied, the conversion and appearance werealso effectively improved.The supported Co catalyst was made by method of dipping with silicon gel or SiO₂as carrier. The activities of supported catalyst and microstructure of polymer werediscussed. It indicates that the activities of supported CoCl₂ by silicon gel or SiO₂ wereclose to the Co(naph)₂-Al(i-Bu)₃-CS₂ catalyst. The catalytic avtivities could beimproved by adding i-BAO into the polymerization system. Compared with solutionpolymerization the catalytic avtivities of bulk polymerization were better, and themolecular weight of product increased.Polymerization and characterization of the blend of s-PB/random -1, 2polybutadiene rubber(A) were discussed. DSC traces of the polymer indicated meltingpoint and crystallinity of s-PB decreased when the content of r-1, 2-PB increased, s-PBand r-1, 2-PB were thermodynamic compatible when they were melted. As the contentof s-PB in s-PB/r-1, 2-PB increased, the mooney viscosity increased and cold flowresistance improved. The blend rubber wasn't cold flow as content of s-PB is 9%.