关键词: 多孔微球, 泡沫, 相分离, 溶剂, 聚合物

Abstract: A novel, simple and efficient method were reported to prepare polystyrene microspheres in foam phase. The key step of the method is that oil droplets were entrained into the foam phase, which was then driven to separate the phases to form porous structures through evaporation of volatile solvent at evaluated temperature. The results showed that the pore morphologies and the particle sizes were influenced by the ratio of polystyrene to porogen (R_-PS/HT), the PVA concentration and the agitation speed. When R_-PS/HT was extremely low, the internal structure of the microspheres became hollow. The particle size of the polystyrene microspheres decreased from 52μm±23μm to 23μm±20μm by increasing the PVA concentration from 1% to 3% and that decreased from 107μm±40μm to 45μm±20μm by increasing the agitation speed from 300r/min to 700r/min respectively. In addition, the porous morphologies were different with different foaming conditions. The reported method also showed a higher yield than the conventional methods of preparing the porous polymer microspheres in water system, especially when the ratio of oil/water phase is more than 1.

Key words: porous microspheres, foam, phase separation, solvents, polymers