The compositional dependence of the polymerization kinetics of multiacrylate copolymers with acrylic acid (AA) was examined. The multiacrylates considered were di- or triacrylate eaters of oligo(ethylene glycol) (OEG). The multiacrylate polymerization rate increased with the OEG chain length in the absence of added AA. This monomer size dependence was due to mobility-related effects on the pendant double-bond reactivity. AA-containing systems exhibited a slight rate enhancement at high conversions, relative to multiacrylate homopolymer formulations, reflecting changes in the fractional concentration of pendant double bonds. These effects were captured in a free volume-based model of the diffusion-controlled polymerization kinetics.