Effect of anethole on the copolymerization of vinyl monomers†
Anethole, a monomer that can be extracted from bioresources, cannot homopolymerize. Its ability to copolymerize with other vinyl monomers depends on both steric hindrance and the electronic nature of the comonomer. Its copolymerization behaviour with acrylic acid, 2-ethylhexyl acrylate, styrene and methyl methacrylate was investigated. Reactivity ratios were determined by the nonlinear least squares method. Even though the presence of anethole strongly retards the rate of consumption of the comonomer, its incorporation in copolymer chains can be improved with semi batch polymerization. Finally, the side reactions that occur during the copolymerizations – e.g. formation of branches or low molecular weight chains – were investigated. We observed that anethole not only acted as a comonomer, but also as a chain transfer agent, likely due to the presence of labile hydrogen.