Quantification of Homopolymer Impurities in Structured Acrylate Copolymers Produced by High‐Temperature Semi‐Batch Radical Polymerization

ABSTRACT Starved‐feed semi‐batch radical polymerization of isobornyl acrylate (iBoA) at high temperatures is used to produce a high macromonomer content polymer without a mediating agent. The p(iBoA) macromonomer solution serves as an addition‐fragmentation agent to synthesize acrylate blocky copolymers via a single‐pot sequential feeding process, as has been demonstrated using n ‐butyl acrylate (BA) as the second monomer. While previous studies confirmed macromonomer incorporation, the copolymer yield was not quantified. In this work, post‐polymerization crosslinking is used to quantify macromonomer incorporation and the impact of reaction temperature and monomer feed ratio. Reaction temperature has little effect on the fraction of copolymer product (70 wt.% at 140°C and 160°C), but strongly influences the relative amount of block versus comb copolymer structure. Maintaining a 50/50 feed ratio of the two monomers is, however, necessary to achieve copolymer levels greater than 60 wt.% in the final product. The ability to synthesize a structured copolymer product by radical polymerization without a mediating agent and control the amounts of block versus comb structure offers the potential to efficiently produce polymeric dispersants for industrial applications.