Controlled Radical Polymerization of Fluorinated Methacrylates in Supercritical CO2: Synthesis and Application of a Novel RAFT Agent

A novel fluorinated reversible addition-fragmentation chain transfer agent, S,S-di-pentaflourobenzyl trithiocarbonate (DPFBTTC), was designed and synthesized. DPFBTTC and dibenzyl trithiocarbonate (DBTTC) were applied in the polymerization of dodecafluoroheptyl methacrylate (DFHMA), hexafluorobutyl methacrylate (HFBMA), and trifluoroethyl methacrylate (TFEMA) in scCO(2). The polymerization processes were monitored using a high-pressure in-situ NIR, through which the polymerization kinetics was investigated and the controllability of DPFBTTC was evaluated. It is found that the controllability of DPFBTTC presented in the order of DFHMA>HFBMA>TFEMA, indicating that DPFBTTC may fit for the controlled polymerization of the highly fluorinated methacrylates. Moreover, the controllability of DPFBTTC is verified to be better than that of DBTTC, possibly resulting from the enhanced accessibility/miscibility of DPFBTTC to the fluorinated monomer used. We believe that the employment of DPFBTTC and the resulted introduction of stable pentafluorobenzyl end groups to the polymer are expected to distinctly improve performances of the polymer, and thus will meet the special application requirements. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 825-834