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 H-1 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.