The Use of High‐Temperature Semi‐Batch Radical Polymerization to Synthesize Acrylate Based Macromonomers and Structured Copolymers

Abstract

AbstractA high‐temperature starved‐feed semi‐batch operating policy is developed to produce p(acrylates) with high macromonomer content, taking advantage of side reactions inherent to acrylate radical polymerization. This operating strategy results in significantly higher macromonomer content for the polymerization of isobornyl acrylate (iBoA) versus n‐butyl acrylate (BA) under identical operating conditions. This is because steric hindrance favors fragmentation (i.e., terminal double bond (TDB) formation) over addition (i.e., short‐chain or long‐chain branch (LCB) formation), thus increasing the p(iBoA) TDB content and decreasing polymer dispersity. The p(iBoA) macromonomer solution serves as an excellent addition‐fragmentation agent to polymerize a second monomer in a single pot process controlled by sequential feeding, as demonstrates by the production of iBoA‐BA block and comb copolymer structures at different temperatures and macromonomer concentrations. The incorporation of the p(iBoA) macromonomer into a copolymer product is verified by various techniques, including polymer fractionation followed by TDB, composition, and molar mass analyses. Reaction temperature plays a key role in determining whether a blocky versus comb copolymer structure is produced. The ability to synthesize block and comb copolymers by radical polymerization without a mediating agent offers the potential to efficiently produce structured copolymers for industrial applications.