Abstract: A class of polymer precursor materials, which, under appropriate conditions, react to form cross-linked polymers, is disclosed. These materials contain a backbone segment, preferably a polyacrylate, and have pendant therefrom (1) reactive mono- or disubstituted olefinic groups, such as vinyl or allyl itaconate, and (2) water-solubilizing groups, such as the half ester of maleic acid. This class of materials, especially when combined with specifically-defined oxygen-activated catalyst systems, provides water-based paint compositions which exhibit film formation, strength and durability characteristics comparable to those of the best solvent-based paint formulations.