Effect of intermolecular interactions on the kinetics of nonyl acrylate radical polymerization

Very high sensitivity of the polymerization rate to dilution of the reaction medium, which is not characteristic of radical polymerization, was found in the polymerization of nonyl acrylate in various solvents (heptane, acetic acid, ethyl alcohol), when chain termination is not diffusion controlled. The role of the solvent was studied under the conditions of diffusion-controlled chain termination, which is achieved in copolymerization of nonyl acrylate with acrylamide or acrylic acid, when interchain interaction becomes stronger due to formation of hydrogen amide-amide or carboxyl-carboxyl bonds. It is suggested that the effect of the solvents is related to the decrease in the rate of chain propagation due to the decomposition of associates with a kinetically favorable arrangement of monomer molecules, and the increase in the rate of chain termination due to the dissociation (upon dilution) of the junctions of the physical network stabilizing the growing polymer chains.