Mechanism and modelling of photo-mediated RAFT step-growth polymerization

Here, we report the modelling of photo-mediated RAFT step-growth polymerization kinetics of maleimide and acrylate monomers with bifunctional RAFT agents bearing tertiary carboxyalkyl stabilized fragementable R groups. We demonstrate that the kinetics for both photo-iniferter and PET-RAFT step-growth polymerizations display a three-half order dependence on monomer conversion. Modelling photo-iniferter RAFT step-growth for both monomer classes discloses that acrylate monomers exhibit lower k_app values compared to maleimide monomers; however, modelling PET-RAFT step-growth indicates that acrylate monomers exhibit higher k_app values compared to maleimide monomers. Furthermore, with the kinetics of thermally-initiated RAFT step-growth, we compare and summarize the kinetic trends based on monomer class, solvent selection, and initiation methods.