Polymerization Kinetics of Styrene Using Coordination Caalysts Containing Rare Earth Compounds

摘要

Polymerization reactions of styrene in toluene at 60°C have been carried out using Ziegler-Natta catalysts containing praseodymium trichloroacetate-triethyl aluminum [Pr(OCOCCis)s-EtsAl] (system 1) and praseodymium trichloroacetate-di- ethyl aluminum bromide [Pr(OCOCCls)s-E~Br] (system lI). The reaction was offirst order with respect to both monomer and catalyst concentrations. At a stoichiometric ratio of Al/Pr = 8, an o,timum catalytic activity was observed. The activation energies for systems I and II ranged between 21.06 kJ/mol and 13.79 kJ/mol, respectively. System I was white in color and system II is waxy. Molar masses of systems I 'and II were 9.1 X 10~5 and 2.2 x 10~4, respectively. The polymers were characterized by viscometry and IH NMR methods.