Polymerization of 1,3-butadiene with metallocene-type vanadium catalyst system - Polymerization rate and polymerization simulation

Cyclopentadienylvanadium complexes (CpV), in combination with triphenylcarbenium tetrakis(pentafluorophenyl)borate (IO) and trialkylaluminum, have been reported to be active catalysts for polymerization of butadiene. Polybutadiene obtained by using them is suitable as graft rubber for High-Impact Polystyrene (HIPS) because of its unique microstructure (cis: -90%, vinyl: -10%). The concentration of active centers and polymerization rate were determined by using a continuous polymerization plant with CPVCl3-Ph3C[B(C6F5)(4)]-Et3Al-H2O as a catalyst system and H-2 as a chain transfer agent and by controlling H-2 concentration by gas-liquid equilibrium. The efficiency of catalyst was evaluated to be 20-30%. The number average molecular weight (M-n) was found to have first-order dependence on monomer concentration ([M]), concentration of active center ([C*]), and the reciprocal of H-2 concentration ([H-2]). A polymerization simulator of this system was constructed using these results.