High-Temperature Radical Copolymerization of Dibutyl Itaconate with Butyl Acrylate, Methyl Methacrylate and Styrene

The feasibility of incorporating a significant fraction of the biorenewable monomer dibutyl itaconate (DBI) into acrylic resins produced by radical copolymerization is studied as a means to increase the sustainable content of coatings. Semibatch starved-feed copolymerizations with methyl methacrylate (MMA) and styrene (ST) are carried out at 110 °C and compared to previous published results for DBI copolymerized with butyl acrylate (BA). Significant composition drift, attributable to the influence of DBI depropagation, limits its incorporation to levels of 35 mol % (∼50 wt %) or lower with all three comonomers under these commercially relevant operating conditions. Copolymerization with MMA at any DBI level is not tenable due to the influence of depropagation. However, constant copolymer compositions are achieved with the addition of up to 35 mol % DBI to the monomer feed for copolymerizations with ST and BA. Reaction rates and polymer molar masses are comparable to the corresponding homopolymer systems, with the DBI/BA copolymerizations characterized by higher conversions but lowered molar masses compared to the DBI/ST system. A set of DBI/BA/ST terpolymerizations demonstrate the ability to tailor the compositions of the synthesized polymers while maintaining the level of biorenewable DBI at 50 wt %.