Poly(vinyl acetate-b-vinyl alcohol) surfactants derived from poly(vinyl ester) block copolymers

A study was conducted to demonstrate syntheses poly(vinyl acetate) (PVAc-b-PVA) amphiphilic block copolymers (ABC) with variable compositions and narrow polydispersities and their micellization in aqueous media. It was demonstrated that the polydispersity of the resulting polymerized vinyl chloroacetate (PVClAc) decreased considerably with increasing concentration of xanthate due to the increased rate of degenerate transfer, also consistent with prior observations for vinyl ester RAFT polymerizations. It was found that sequential block copolymerization of VAc followed by VClAc yielded PVAc-b-PVClAc diblock copolymers, with slightly broader polydispersities due to the relatively electron-rich nature of the PVAc-RAFT agent that slowed macromolecular chain transfer agent initialization. Representative size exclusion chromatography (SEC) traces of PVAc-b-PVClAc-2 and PVClAc-b-PVAc-4 demonstrated that these highly efficient chain extension reactions produced unimodal polymers with narrow molecular weight distributions.