溶剂挥发法制备大孔聚合物微球

Preparation of macroporous polymer microspheres by a solvent evaporation method

以乙基纤维素(EC)和具有pH敏感性的聚丙烯酸树脂Ⅳ(PAR)为原料,通过溶剂挥发法制备大孔聚合物微球。聚合物浓度和乳化剂聚乙烯醇(PVA)的浓度影响聚合物微球的粒径大小,聚合物浓度减小或乳化剂浓度增大有利于形成较小的微球。研究了pH和PAR/EC质量比对微球孔结构、比表面积的影响,分析了微球多孔结构形成的机理。溶液的pH可改变PAR的亲疏水性,影响微球的孔结构:酸性环境中得到的微球表面出现致密的大孔,内部是复杂的多孔网络结构,碱性环境中则得到表面无孔的微球。因此,可通过调节溶液PAR/EC质量比和pH来调控微球的孔结构。

Macroporous polymer microspheres were prepared using ethyl cellulose(EC) and pH-sensitive polyacrylic resin Ⅳ(PAR) by a solvent evaporation method. The particle size of polymer microspheres was affected by the concentrations of polymers and emulsifier polyvinyl alcohol(PVA). The reduction of polymer concentration or the increase of emulsifier concentration was beneficial for the formation of microspheres with smaller size. The effects of pH and PAR/EC mass ratio on the pore structure and specific surface area of microspheres were studied. The results show that the change of solution pH affects the hydrophilicity of PAR, which results in different pore structures of microspheres. The microspheres synthesized in acidic solution have dense surface macropores and complex inner porous network structures, while nonporous microspheres can be obtained in alkaline environment. Therefore, the pore structure of microspheres can be regulated by adjusting PAR/EC mass ratios and solution pH.