Synthesis of nanocomposites by macroRAFT-assisted emulsion polymerization

Abstract

The aim of this work is to prepare clay or silica-based nanocomposite latexes by aqueous emulsion polymerization, using the reversible addition-fragmentation chain transfer (RAFT) polymerization. Hydrophilic polymers (macroRAFT) composed of poly(ethylene glycol) (PEG), acrylic acid (AA) or N,N-dimethylaminoethyl methacrylate (DMAEMA) and comprising hydrophobic n-butyl acrylate (BA) units (in some cases) and trithiocarbonate terminal group were initially synthesized. Then, the interaction between the macroRAFTs and the inorganic particles was studied through the plot of adsorption isotherms. By acting as coupling agents and stabilizers, the macroRAFT agents were used in the emulsion copolymerization of methyl (meth)acrylate and BA by semi-continuous process in the presence of the inorganic particle. Hybrid latex particles with different morphologies were obtained and the results can be associated to the nature and concentration of the RAFT (co)polymers, to the pH of the dispersion, the glass transition temperature of the final copolymer and to the polymerization conditions. (AU)