Iran Polymer and Petrochemical Institute Polyolefins Journal 2322-2212 9 2 2022 07 01 The influence of the oxygen donor capacity of polystearylmethacrylate over polyethylene bulk density when using modified methylaluminoxane as co-catalyst 93 101 1859 10.22063/poj.2022.3095.1210 EN Odilia Pérez-Camacho Departamento de Química Macromolecular y Nanomateriales, Centro de Investigación en Química Aplicada, 25294, Saltillo, Coahuila, México Eduardo Cardozo-Villalba Departamento de Química Macromolecular y Nanomateriales, Centro de Investigación en Química Aplicada, 25294, Saltillo, Coahuila, México 0000-0001-5100-3103 Journal Article 2022 01 12 In this work, the interaction between a polystearylmethacrylate (M<sub>n</sub> = 8,900 g mol-1, X<sub>n</sub> = 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 <sup>1</sup>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<sup>-3</sup>) concerning blank reactions (0.26 g cm<sup>-3</sup>). metallocene catalyst oxygen donors Methylaluminoxane Ethylene polymerization bulk density http://poj.ippi.ac.ir/article_1859_233f15586db6e6013dc288eb2d84ce5c.pdf