Synthesis of Polymer Colloids Using Polymerizable Surfactants

Abstract

A series of new anionic surfactants were prepared by reacting a polymerizable alcohol with either maleic or succinic anhydride, as well as sulfosuccinic anhydride, resulting in either bireactive or monoreactive surfactants, either carboxylated or sulfonated. The synthesis presented and the critical micelle concentration (CMC) determined. These compounds were engaged in the emulsion polymerization of styrene in batch and also in semi-batch seeded copolymerization producing core-shell latexes. The core was a polystyrene seed prepared using sodium dodecyl sulfate (SDS), thoroughly purified through ion exchange resins. The seed was then swollen overnight with a small amount of a 1 : 1 mixture of styrene and butyl acrylate, and finally fed with the same mixture together with the reactive surfactant. The amount of monomer was calculated so that, from a seed with a diameter of 100 nm, a core-shell latex of 150 nm was obtained. The amount of surfactant was such that a coverage of 80% was aimed for. The calculated solid content was 9%. Using 3.5 wt.-% of surfactant (versus monomer), the conversion reached about 90%, the floc being limited most often to less than 2%. The target diameter of the core-shell latex was nearly obtained. The latexes were stable only with limited amounts of added electrolytes and failed the test of freeze-thawing. About 40–50% of the surfactant were located on the surface.