title: Selective and Quantitative Oxidation of Xanthate End-Groups of RAFT Poly(n-butyl acrylate) Latexes by Ozonolysis.
abstract: Although various successful strategies have been reported in the past for the postpolymerization modification of the reversible addition-fragmentation chain transfer (RAFT) terminal group in homogeneous media, no solution is proposed for the tedious case of aqueous polymer dispersions where most of the thiocarbonylthio terminal group is buried into the core of the polymer particle. In this work, ozone is proposed to tackle this important academic and industrial challenge. After preliminary model ozonolysis reactions performed on a xanthate RAFT agent and a derived low molar mass poly(n-butyl acrylate) (PBA) in dichloromethane solution, it is shown that the hydrophobic nature and strong oxidant properties of ozone are responsible for its efficient diffusion in aqueous PBA latex particles obtained by RAFT and selective and complete transformation of the xanthate terminal group into a thiocarbonate end-group. In addition to the beneficial total discoloration of the final product, this chemical treatment does not generate any volatile organic compound and leaves the colloidal stability of the polymer particles unaffected, provided that a PBA latex with a sufficiently high Mn of 5000 g mol(-1) is selected.
authors.affiliation: LHFA, UMR CNRS 5069, Université Paul Sabatier Toulouse III, 118 route de Narbonne, F-31062, Toulouse, Cedex 9, France.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Matioszek
authors.affiliation: High Barrier Polymers, SOLVAY, Avenue de la République, F-39500, Tavaux, France.
authors.forename: Pierre-Emmanuel
authors.initials: PE
authors.lastname: Dufils
authors.affiliation: High Barrier Polymers, SOLVAY, Rue de Ransbeek 310, B-1120, Brussels, Belgium.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Vinas
authors.affiliation: IMRCP, UMR CNRS 5623, Université Paul Sabatier Toulouse III, 118 route de Narbonne, F-31062, Toulouse, Cedex 9, France.
authors.forename: Mathias
authors.initials: M
authors.lastname: Destarac
mesh_terms: D000179:Acrylates / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D007840:Latex / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D010126:Ozone / Q000737:chemistry*; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000179:Acrylates; D005609:Free Radicals; D007840:Latex; D011108:Polymers; C498324:poly(n-butyl acrylate); D010126:Ozone
keywords: controlled/living radical polymerization; emulsion polymerization; ozonolysis; reversible addition-fragmentation chain transfer; xanthates