Gas phase ethylene polymerization over SiO2-supported organosilyl chromate UCC S-2 catalyst using a high-speed stirred-autoclave reactor

Abstract

Although an important industrial catalyst for producing high density polyethylene, the SiO 2 -supported organosilyl chromate UCC S-2 catalyst has not been fully investigated compared with the SiO 2 -supported oxo chromium Phillips catalyst. In this work, gas phase ethylene polymerization by S-2 catalysts (Cat-1, Cat-2, and Cat-3) was carried out in a high-speed stirredautoclave reactor. The effects of temperature, time, and pressure on kinetics, activity, and product properties were studied. All kinetics were typical built-up types with slow decay. Compared to the simple physical mixtures of Cat-1 and Cat-2, Cat-3 showed higher activity and its product had a broader molecular weight distribution, indicating new active species induced during blending of Cat-1 and Cat-2 in n-hexane. The innovation by a simple catalyst technology created a new application to meet market demands.

Gas phase polymerization of ethylene towards UHMWPE

“…Temperature and pressure are the most important parameters which affect the molecular weight and polymerization activity. While the increase in temperature decreases the molecular weight of the polymer due to the increase of chain transfer more than chain propagation, molecular weight increases with pressure depending on the increase in the ethylene insertion [17]. For the polymerization activity, temperature was found to be the most important factor, and has an important relation with pressure and cocatalyst.…”