Free-Radical Homopolymerization Kinetics of Biobased Dibutyl Itaconate

Free-radical polymerization of dibutyl itaconate (DBI), a monomer sourced from renewable feedstocks, was studied to determine the possibility of its incorporation into commercial acrylic resins as a route to improve the sustainability of coating materials. Batch experiments in deuterated and protonated toluene at 50 and 80 °C with different initial monomer and initiator contents were conducted. A kinetic model was developed to guide the experimental studies. Samples were analyzed using 1H NMR and size-exclusion chromatography to determine conversion profiles and polymer molar mass distributions, with the experimental results compared with the simulation to validate the model and improve estimates of key kinetic rate coefficients. Both the polymerization rate and polymer molar masses are influenced by depropagation as the reaction temperature is increased from 50 to 80 °C, demonstrating an inherent limitation to the commercial production of poly(itaconate) homopolymer. However, the first results indicate that semibatch operating conditions close to current industrial practice can be used to incorporate a substantial fraction of the bioderived monomer into acrylic copolymer resins.