New polymeric photoinitiators with pendant alpha-aminoacetophenone moieties, such as the homopolymers of 1-(4-morpholinophenyl)-2-benzyl-2-[N-methyl-N-(3-methacryloyloxypropyl)]aminopropan-1-one and of 1-(4-morpholinophenyl) -2-benzyl-2- [N-methyl-N-(3-methacryloyloxypropyl)]aminobutan-1-one have been prepared and fully characterized. Their photoinitiation activity has been also checked in the ultraviolet cure of a standard acrylic mixture, under irradiation over 380 nm, thus simulating the absorption conditions of a TiO2-pigmented coating formulation. The results have been compared with those found by using the corresponding low-molecular-weight structural models, purposely synthesized. The activity data obtained are discussed and related to the structural requirements of the above systems. 1997 John Wiley & Sons, Inc.