Amphiphilic graft; copolymers of definite composition were obtained by grafting of aminofunctionalized poly(oxyethylene) monoether (MPEO-NH2) of M(n) = 750, 2000, and 5000 onto phthalimidoacrylate (PIA) homopolymer or its copolymer with styrene (St). The radical copolymerization of PIA and phthalimidomethacrylate (PIMA) with St was studied in dimethylformamide (DMF) at 60 degrees C. The copolymer composition curves and the monomer reactivity ratios showed a high tendency of PIA to alternating copolymerization with St (r(1)r(2) = 0.006). Hydrogen bonding between the functional groups leads to significant spectral modifications. The micellization of the graft copolymers was studied by GPC in aqueous-methanolic eluent. The aggregation behavior of the graft copolymers depended on their composition and chromatographic separation lead to the copolymers fractionation.