RAFT Polymerization of a Renewable Ricinoleic Acid-Derived Monomer and Subsequent Post-Polymerization Modification via the Biginelli-3-Component Reaction

The search for renewable monomers for radical polymerization techniques is of current interest due to the awareness of sustainability requirements in the chemical sciences. Herein, the synthesis and reversible addition-fragmentation chain-transfer (RAFT) polymerization of a renewable methacrylate monomer based on ricinoleic acid as sustainable starting material is presented. In addition, the hydroxy moiety of the ricinoleic acid is converted to an acetoacetate in order to allow for a post-polymerization modification (PPM) using the Biginelli-three-component reaction (B-3CR), rendering the presented monomer a renewable and highly flexible reactant for the synthesis of polymer materials. Consequently, RAFT polymerization yields macromolecules with a molecular weight of up to 15 000 g mo$^{-1}$l and expectedly narrow molecular weight distributions with Ðs around 1.13. The feasibility of chain extension and block copolymer synthesis is demonstrated. Eventually, the PPM of the acetoacetate moiety of the polymer repeating units using the B-3CR is proven to be efficient with conversions of up to 95% of the acetoacetates, while the modification allows for a pronounced increase of the glass transition temperature to approximately room temperature compared to the unmodified polymers (T$_{g}$ = −50 °C).