External donor modified Mg-Ti based Z-N catalyst system for synthesis of Ultrahigh molecular weight polyethylene

Abstract

This study reported novel external donors Diethyl 2,2'-(dimethylsilanediyl) diacetate (DSD1), Diethyl 2,2'-(phenyl(methyl) silanediyl) diacetate (DSD2) and Diethyl 2,2'- (diisopropylsilanediyl) diacetate (DSD3) and triethyl borate (TEB) employed with magnesium dichloride supported Ti-based monoester (Mg-Ti-ME) and magnesium dichloride supported Ti-based diester (Mg-Ti-DE) catalyst for synthesis of Ultrahigh molecular weight polyethylene (UHMWPE). Furthermore, the catalyst was tested with different concentrations of chain-terminating agents to understand the effect on molecular weight. The results showed Mg-Ti catalysts using DSD1, DSD2, and DSD3 and TEB external donors had significantly increased molecular weight in the presence of external donors with decreases in catalyst activity, compared to donor-free catalyst systems. In addition, in the presence of chain terminating agent molecular weight decreases significantly with less effect on catalyst activity. The obtained polymer, thermal properties characterized through differential scanning calorimetry (DSC), morphology through a scanning electron microscope (SEM), particle size of resin through a particle size analyzer and molecular weight through viscosity-average molecular weights method.