Free-radical solution copolymerization of acrylamide (AAm) and of a disubstituted acrylamide derivative, N-acryloylmorpholine (NAM), with N-acryloxysuccinimide (NAS) was investigated with the aim to obtain a copolymer of at least 100,000 g mol(-1). Different polymerization conditions likely to increase the molecular weight were studied such as monomer and initiator concentrations, temperature, and nature of the solvent. The molecular weights were determined by SEC using a light-scattering detector. The grafting of end-functionalized polysaccharide chains onto such high molecular weight poly(NAM-co-NAS) was performed and a graft copolymer bearing a high number of saccharidic branches was obtained. (C) 2003 Wiley Periodicals, Inc.