Copolymerization of ethylene withdifferent α-olefins with poly(styrene-co- Divinylbenzene)-supported Cp[subscript 2]ZrCl[subscript 2]/MAO catalyst

Abstract

The study reveals the use of poly(styrene-co-divinylbenzene) as a support for Cp[subscript 2]ZrCl[subscript 2]/MAO catalyst for copolymerization of ethylene/α-olefins. It was aimed to determine the effect of comonomer chain length and ethylene/α-olefin ratios on the catalytic activity and properties of the polymer. Ethylene/α-olefins copolymerization reactions were carried out in a 100 mL semi-batch stainless steel autoclave reactor, activated by MAO cocatalyst at 70 °C and 6 psi of ethylene pressure at various initial comonomer type and comonomer concentrations. From the analysis of the resulting support particles by SEM, it was found that the active species are located on the particle surface and they have uniformly distributed throughout the particles. The activities of ethylene/α-olefin copolymerization increased with the increase of the comonomer concentration until the maximum was reached and then started to decrease with further increase of comonomer concentration. Moreover, The length of the chain of the comonomer and comonomer concentration had little effect on activities and activity profiles of copolymerization. The properties of copolymers produced were characterized by means of SEM, 13C NMR and DSC. Based on 13C NMR and DSC, all copolymer exhibited the similar distribution having the majority for the triad of EEE and melting temperature decreased slightly with increasing comonomer concentration.