Polymerization kinetics of styrene using coordination catalysts containing rare earth compounds

Polymerization reactions of styrene in toluene at 60°C have been carried out using Ziegler–Natta catalysts containing praseodymium trichloroacetate‐triethyl aluminum [Pr(OCOCCl 3 ) 3 ‐Et 3 Al] (system I) and praseodymium trichloroacetate‐diethyl aluminum bromide [Pr(OCOCCl 3 ) 3 ‐Et 2 AlBr] (system II). The reaction was of first order with respect to both monomer and catalyst concentrations. At a stoichiometric ratio of Al/Pr = 8, an optimum 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 × 10 5 and 2.2 × 10 4 , respectively. The polymers were characterized by viscometry and 1 H NMR methods. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 995–1002, 2001