New insights into the catalyst and cocatalyst pre‐contact process in ethylene copolymerization

Abstract The influence of pre‐contacting time and temperature as well as mixing intensity on polyethylene copolymerization has been investigated employing DSC, rotational rheometry tests, as well as particle size distribution analysis. For this purpose, a commercial‐supported Ziegler–Natta catalyst has been pre‐contacted with Teal as cocatalyst under different time, temperature, and stirring speed followed by similar polymerization process. It was found that the increase in mixing intensity has no impact on rheological properties; it causes increase in crystallinity percentage of polymer due to better distribution of active centers. Moreover, the pre‐contacting time represents the most impact on catalyst activity and rheology of polymer powder while the pre‐contacting temperature changes is mostly effective on controlling the morphology of polymer. Additionally, the results reveal that 10‐min pre‐contacting of catalyst and Teal under 10°C and stirring speed of 500 rpm was accompanied by highest catalyst activity and lowest content of fine particles. Highlights Pre‐activation was studied under different time and temperature. Adjusting pre‐contacting time influences the polymer morphology. Pre‐contacting under lower temperature results in narrower molecular weight distribution.