Abstract
Porous polymer microspheres of poly(methyl methacrylate-co-trimethylolpropane triacrylate)[P(MMA-co-TMPTA)] were prepared by in-situ polymerization using the multiple emulsion (W/O/W emulsion), which was prepared by the two-step emulsification method. TMPTA was added as the cross-linking agent to increase the mechanical strength and the organic solvent-resistant. It was investigated how the conditions at the first step emulsification (W/O), the kinds and concentrations of surfactant in the oil phase and the concentration of salt in the inner water phase affected the morphology and the hollow degree of microspheres. From these results, it was found that oil soluble glycerol surfactant (OSGS) was effective as a surfactant for preparing the W/O emulsion and the finer internal structure of polymer microspheres was formed with the concentration of OSGS in the oil phase. Furthermore, by addition of NaCl into the inner water phase and increasing the concentration of NaCl, the entrapment efficiency of the inner water phase and the hollow degree of microspheres were found to be increased. Furthermore, it was found that the higher hollow degree of polymer microsphere was able to be obtained by increasing the volume ratio of the inner water phase and the stability of the W/O dispersion.
