Block copolymers as polymeric surfactants in latex and microlatex technology

Polystyrene-poly(ethylene oxide) PS-PEO di- and triblock copolymers were us ed as non-ionic stabilizers in the emulsion polymerization of styrene and s tyrene-butyl acrylate for the preparation of 'hairy latexes'. The efficienc y of these polymeric surfactants was correlated with the molecular characte ristics of the block copolymer. It was shown that the efficiency decreased with increasing molecular weight and PS content of the block copolymer. Acr ylic microlatexes with a particle size below 50 nm could be obtained with P S-PEO and PMMA-PEO diblock copolymers. Crosslinking of these microlatexes l eads to the formation of microgels dispersible with adjustable swelling in organic solvents. 'Hairy' latexes are also prepared with poly(methyl methac rylate)-poly(acrylic acid) PMMA-PAA diblock copolymers as ionic surfactants . The swelling of the PAA fringe of the latex by neutralization is demonstr ated. (C) 1999 Elsevier Science B.V. All rights reserved.