One-pot synthesis of poly(vinylidene fluoride) methacrylate macromonomers via thia-Michael addition
This study presents a new synthetic route to prepare original PVDF macromonomers and PVDF-based architectures. A poly(vinylidene fluoride), PVDF, synthesized using MADIX controlled polymerization in the presence of O-ethyl-S-(1-methoxycarbonyl)ethyldithiocarbonate was chemically modified via two strategies and fully characterized. Using a one-pot procedure, the xanthate end-groups of the PVDF were converted into thiols which were immediately added onto the acrylate moieties of 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHPMA) via regioselective thia-Michael addition to form new PVDF-MA macromonomers. Two methods of elimination of the thiocarbonylthio group were tested and compared: aminolysis, and elimination using sodium azide. These reactions were thoroughly examined via1H and 19F NMR spectroscopy and SEC-HPLC. The aminolysis procedure was shown to give better coupling efficiency and better-defined macromonomers. The PVDF-MA macromonomers with the highest functionality were further polymerized by RAFT. The RAFT homopolymerization of PVDF-MA revealed that a non-negligible amount of macromonomers did not react. In contrast RAFT copolymerization of PVDF-MA and MMA resulted in the total conversion of the macromonomers and allowed the synthesis of novel methacrylic copolymers and block copolymers.