SWELLING OF POLYBUTADIENE AS LATEX-PARTICLES AND CAST FILMS BY STYRENE AND ACRYLONITRILE MONOMERS

During emulsion polymerization, the diene structure of butadiene leads to the formation of a network by crosslinking on the residual double bonds. Investigation of the swelling of polybutadiene particles and films cast from latexes, by styrene and acrylonitrile, was carried out in order to get more information on polymer structure and behaviour in the presence of monomers. A thermodynamic approach has permitted us to determine several parameters, such as the average number of butadiene units between two crosslinking points, which represents the crosslink density and was compared with data from simulation of butadiene emulsion polymerization. Swelling by monomer mixtures of various compositions has shown a preferential solvation of styrene as a function of comonomer composition. Comonomer composition in the particles is important in the final structure of an acrylonitrile-butadiene-styrene particle prepared by emulsion polymerization of styrene-acrylonitrile on a polybutadiene seed. Diffusion coefficients of monomers were determined after a kinetic study.