Suspension Photopolymerization of Methyl Methacrylate and ATRP Grafting of Thermo-Responsive Polymers Using a Perylediimide Derivative Photoinitiator

The first aim of this study is to develop a photo-ATRP process using methyl methacrylate (MMA) by employing a novel perylenediimide derivative (PDI) as photoinitiator. The analysis of the MMA photopolymerization process kinetics is performed in solution and in bulk, demonstrating control over the reaction progress even if the polymerizations display a slow initiation step. The photo-ATRP process for MMA in suspension is also developed and the obtained PMMA particles are further used to reinitiate the ATRP polymerization of thermoresponsive polymers (different molecular weights poly(ethylene glycol) methyl ether methacrylate and poly(N-isopropylacrylamide)) (PNIPAM) in solution and surface-initiated processes. The synthesized polymers by surface-initiated process display a bimodal molecular weight distribution with a clear modification of the signal areas ratio depending on the grafted monomer and on the reaction conditions. The grafting process can take place on the surface of the polymer particles (Mn2), or it can also involve polymer chains located further at the interior of the polymer particles (Mn1). The lower critical solution temperature (LCST) transition is demonstrated for the PNIPAM functionalized polymer particles. A perylene diimide derivative is synthesized and used as photoinitiator for atom transfer radical polymerization of methyl methacrylate. Surface-initiated polymerization confirms the controlled characteristic by exploiting the presence of terminal bromine on the surface of the particles obtained by suspension. The poly(N-isopropylacrylamide) grafts on the surface of the particles lead to an increase of the lower critical solution temperature transition.image