PARTICLE MORPHOLOGY IN VINYL-ACETATE BUTYL ACRYLATE EMULSION COPOLYMERS

Vinyl acetate (VA)-butyl acrylate (BA) emulsion copolymers with various comonomer ratios have been prepared by different emulsion polymerization pathways (conventional batch, semi-continuous addition, with and without emulsifer, composition-controlled batch, core-shell copolymerization) with a view to investigating synthesis-structure-property relationships. Special attention has been paid to the characterization of particle morphology as a function of monomer feed composition and polymerization process. Evidence of particle morphology can be accessed by combining a detailed analysis of emulsion polymerization kinetics of this system with a thorough characterization of the molecular (glass transition temperature, monomer sequence distribution) and colloidal (polarity of particle surface, morphology) properties of the copolymer latexes. In addition, dynamic mechanical measurements have been performed on films cast from these latexes ; their behavior was compared with computer simulated moduli variation vs. temperature and frequency providing useful information on the film morphology in relation with that of particles.