Soluble polymeric catalysts containing benzyltrialkylammonium chloride moieties and styrene or N,N‐dimethylacrylamide as a polar unit were prepared by copolymerization of vinylbenzyl chloride and the corresponding monomer, and then quaternization of the chloromethyl group by trialkylamines. The addition reaction of glycidyl methacrylate and carbon dioxide proceeded effectively using these polymer‐supported quaternary ammonium salts. The catalytic activity was affected by the amount of vinylbenzyl chloride, type of reaction solvent, and the structure of trialkylammonium salt due to the balance between lipophilicity and steric hindrance of the pendant quaternary ammonium salt. A kinetic study was also carried out to better understand the reaction steps. Copyright © 2003 John Wiley & Sons, Ltd.