Preparation and Characterization of Polymer Core/Shell Latex Particles

Seed latex with narrow particle size distribution was first prepared by emulsion polymerization with styrene and butyl acrylate as monomers and varying amounts of emulsifiers and initiators,which was then used to achieve stable core/shell latex with second stage monomers consisting of methyl methacrylate,ethyl acrylate and methacrylic acid(MAA),by batch and semi-continuous emulsion polymerization.Particles size and morphology of the latexes prepared by the two processes were compared.The effects of methacrylic acid amount on latex properties were studied.Experiment results show that monodisperse core-shell latex particles is obtained when the mass ratio of core/shell is kept at 5 ∶2 with MAA mass content between 3% and 5% in the shell formation monomers.And the particle size distribution of the latexes prepared by semi-continuous technique is narrower than those prepared by batch process.With increasing the amount of MAA in polymerization,the stability of latex deteriorates,and particle size and size distribution increase with more strawberry latex particles.