Graft Copolymers from Poly(vinylidene fluoride-co-chlorotrifluoroethylene) via Atom Transfer Radical Polymerization

We report the grafting of polystyrene (PS) and poly(tert-butyl acrylate) (PtBA) from poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-co-CTFE)) via atom transfer radical polymerization (ATRP). The initiating sites on P(VDF-co-CTFE) for the graft copolymerization are the secondary chlorines, indicated by the model reactions using poly(chlorotrifluoroethylene) (PCTFE) oligomer and the control experiment using poly(vinylidene fluoride) (PVDF). The formation of graft copolymers, P(VDF-co-CTFE)-g-PS and P(VDF-co-CTFE)-g-PtBA, was confirmed by 1H NMR, size exclusion chromatography (SEC), differential scanning calorimetry (DSC), and atomic force microscopy (AFM) measurements. The hydrolysis of PtBA grafts in P(VDF-co-CTFE)-g-PtBA resulted in amphiphilic graft copolymers with hydrophilic poly(acrylic acid) (PAA) side chains. The synthetic approach reported here offers a convenient way to modify commercial fluoropolymers containing CTFE units. The resultant graft copolymers may find potential applications such as materials for filtration membranes.