Synthesis of fluorinated gradient copolymers by RAFT emulsifier-free emulsion polymerization and their compatibilization in copolymer blends

The gradient copolymers of styrene and fluorinated acrylate were synthesized by reversible addition-fragmentation transfer (RAFT) emulsifier-free emulsion polymerization under the control of amphiphilic RAFT agent. The polymerization conditions were studied in detail. Molecular weights were traced by gel permeation chromatography (GPC) during the polymerization process. The copolymer structures were characterized by H-1 NMR, Fourier transform infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC). These results proved that the copolymer had a gradient chain structure. The gradient copolymer was used as a compatibilizer to improve the compatibility of the polystyrene/fluoropolymer blend. The effects of molecular weight and adding content of the gradient copolymer on the compatibilization were studied.