Effect of Hydrogen on Propylene Polymerization with TiCl₃-Al(C₂H₅)₃

Abstract

The effect of hydrogen on propylene polymerization with TiCl₃-Al(C₂H₅)₃ is studied. The following results are obtained from the polymerization rate and the isotacticities and the molecular weights of the polymers produced in the presence of hydrogen.
The polymerization rate decreases with hydrogen pressure as e xpressed by
where, R_∞^H, and R_∞^O are the stationary polymerization rates in the presence and in the absence of hydrogen, respectively. The apparent activation energy of a was negative. We propose a reaction mechanism which contains the recovery of polymerization centers deactivated temporarily by the adsorption of hydrogen. This recovery needs cocatalyst, Al(C₂H₅)₃, and propylene. The transfer rate obtained from the molecular weight of polymers supports the above reaction mechanism.