the influence of the oxygen donor capacity of polystearylmethacrylate over polyethylene bulk density when using modified methylaluminoxane as co-catalyst

I n this work, the interaction between a polystearylmethacrylate (mn = 8,900 g mol-1, xn = 26, ð = 1.1) and modified methylaluminoxane 12 (mmao-12) co-catalyst is studied using different spectroscopic methods. the effect of this oxygen-donor additive was measured by the changes in the bulk density of the raw polyethylene, which resulted increased respect to those obtained in blank reactions. a decrease in the activity was also observed as a penalty for the improvement of the bulk density, enhancing the possibility of reducing fouling. the coordination of the carbonyl oxygen groups of polystearylmethacrylate to aluminum (iii) centers is confirmed by 1 h-nmr and ftir studies, and by a simple semi-empirical computational calculation. a method for obtaining a tri-component co-catalyst mixture is described using the methyl-bridging capacity of trimethylaluminum and its lewis acidity to get the polystearylmethacrylate and mmao-12 linked together. this robust adduct introduces a hierarchy over the pe chain growing, leading to higher bulk densities for pe beads (0.43 g cm^-3) concerning blank reactions (0.26 g cm^-3).