文摘
Surfactant-free emulsion polymerization for the synthesis of poly(methyl methacrylate)/poly(vinylamine) (PMMA/PVAm) amphiphilic core-shell polymer particles is investigated in this work. Particularly, the effect of the PVAm molar mass and the tert-butyl hydroperoxide (TBHP)/PVAm molar ratio on the kinetics of reaction and particle nucleation is studied, and the morphology of the polymer particles carefully analyzed. Interestingly, decreasing the TBHP/PVAm molar ratio leads to faster kinetics of the polymerization reaction. Decreasing the molar mass of PVAm also yields faster kinetics. The morphology of the PMMA/PVAm polymer particles is core-shell like, and the PVAm chains are located at the surface of the polymer particles acting as stabilizer. Thus, the pH affects their morphology and the PVAm chains are fully extended at low pH and hence are swollen by water and have large size, whereas at high pH, the PVAm chains shrink and particle sizes are smaller.