Impact of Process Variables on Properties of Polypropylene Derived from the Supported Ziegler-Natta and Metallocene Catalysts

The present study reveals some aspects on properties of polypropylene (PP)derived from the supported Ziegler-Natta (ZN) catalyst (MgCl2/TiCl4/DEP) andthe supported metallocene (MC) catalyst (SiO2/MAO/Et[Ind]2ZrCl2).Experimentally, PPswere produced using the supported ZN and MC catalysts as mentioned above by varying the conditions such as the polymerization temperatures,propylene pressure, and the [Al]cocatalyst/[Ti]ZN catalyst or [Zr]MC catalyst ratios. Based on the study, it was found that activities, mmmm(%) or isotactivity, and meltin temperatures(Tm) apparently depended on the polymerization temperatures, propylene pressures,and [Al]cocatalyst/[Ti] or [Zr]catalyst ratios in different ways. The impact of eachprocess variable on the properties of PP obtained was further discussed in more details. In general, it was found that the supported MC catalyst provided more active species compared to the supported ZN catalyst leading to higher activities. In particular, the PP produced from the supported MC catalyst also had high isotacticity, however, lower Tm compared to that produced from the supported ZN catalyst. It is worth noting that by changing those parameters, the properties of PP can be altered based on the nature behaviour of the two catalysts. As a matter of fact, the process variables can be chosen in order to achieve the desired properties of PP under the supported catalytic system.