EMULSION COPOLYMERIZATION OF STYRENE WITH A NONIONIC STYRENIC POLYMERIZABLE SURFACTANT

Among the variety of possible structures for polymerizable surfactants, it seems clear that the most interesting should be those with the reactive group located in the hydrophobic part of the molecule. We report here a study based on such a surfactant. Its general formula is CH2=CH-C6H4-CH2-O(CH2)(n)- O(CH2CH2-O)(m)-H A set of surfactants has been produced with m varying from 23 to 48 and n 6 or 12. The compounds have been characterised by H-1-NMR (nuclear magnetic resonance), size exclusion chromatography, surface tension measurements and turbidimetry. These surfactants have been copolymerized with styrene in emulsion polymerization. The coagulum is rather important, except if m is large enough. Although the incorporation of the surfactant in the latex particles remains limited, the surface tension of the latex is rather high. Most of the anchored surfactant remains at the surface and is not too buried inside. The particle size decreases with both the amount of surfactant and the length of its hydrophilic part. The use of these polymerizable surfactants leads to an excellent stability of the latex against the addition of electrolytes, and also against freeze-thawing constraints.