Aqueous polymerization of methyl methacrylate catalyzed by corundum and characterization of the obtained polymers

The aqueous polymerization of methyl methacrylate (MMA) was studied using sodium bi-sulfite as initiator in the absence and presence of corundum (Al₂O₃). It was found that corundum has a catalytic effect on the polymerization reaction. The polymers obtained in the presence of corundum were found to have a wider molecular weight distribution than in its absence; this was deduced by thin-layer chromatographic analysis in a binary mixture (benzene: methanol 1:1.5 by volume) at 25°C. The apparent energy of activation was calculated between 40 and 50°C, and was found to be 4.50 × 10⁴ and 1.70 × 10⁴ J/mol in the absence and presence of 0.5 g corundum (type 600 grit)/105 mL of the reaction mixture, respectively.