Preparation of a xanthate-terminated dextran by click chemistry:: Application to the synthesis of polysaccharide-coated nanopartides via surfactant-free ab initio emulsion polymerization of vinyl acetate

Stable monodisperse poly(vinyl acetate) (PVAc) submicronic latex particles were synthesized by ab initio batch emulsion polymerization using a dextran derivative from renewable resource as an efficient steric stabilizer. The dextran end-functionalized by a xanthate moiety was synthesized by Huisgen's 1,3-dipolar cycloaddition (click chemistry). It was applied as a macromolecular RAFT (reversible addition fragmentation chain transfer) agent in surfactant-free emulsion polymerization of vinyl acetate to form in situ an amphiphilic block copolymer able to efficiently stabilize the latex particles. The method afforded the preparation of high solids content (27%) latices coated by dextran. Both the kinetic study and the molar mass analyses confirmed the involvement of the dithiocarbonate group in the emulsion polymerization process. (c) 2008 Wiley Periodicals, Inc.