Synthesis of Core-Shell Latex Particles Through One-Step Emulsion Polymerization

Abstract

Polystyrene/polyacrylate acid (PSt/PAA) core-shell latex particles were obtained through a one-step emulsion polymerization by making use of controlled distribution of the reaction monomer at different temperatures. The polymerization conversion and stability were characterized to find appropriate synthetic conditions. The results show that the mixed solution of certain proportions of St, AA, and distilled water were inhomogeneous at lower temperature, e.g. 25°C, but the mixed solution would become more and more homogeneous with increasing temperature. The mixed solution became completely homogeneous at 75°C. After this, according to the results of uniformity degree change, the pre-emulsion temperature was set at 75°C, and the polymerization temperature was 65°C. α,α-Azobisisobutyronitrile was used as initiator. Stable latex and latex particles, with obvious core-shell structure, were obtained. The composition of the mixed solution was characterized by UV-vis spectrophotometry. The morphology of latex particles was observed using transmission electron microscopy and scanning electron microscopy. The research provides a new method to obtain polymer particles with a core-shell structure.