单分散窄分布PMMA微球的制备工艺研究

通过分散聚合法,以甲基丙烯酸甲酯为单体,以聚乙烯基吡咯烷酮(PVP)为分散剂、偶氮二异丁腈(AIBN)为引发剂、甲醇/水为分散介质,并二次滴加单体与分散介质混合液,制备微米级单分散聚甲基丙烯酸甲酯微球.通过傅里叶转换红外分析,场发射扫描电镜,激光粒度分析等对微球进行表征.研究反应时间、初始单体浓度、分散剂浓度和引发剂用量等因素对微球粒径及粒径分布的影响.引发剂浓度和分散剂用量是影响聚合物微球粒径主要因素.分散剂浓度增大,引发剂浓度减小,均使微球粒径减小,分布变窄.最佳工艺条件为PVP用量1.5%、AIBN用量1%、单体用量10%、甲醇用量为60%、反应时间为6h、温度为75℃、制得的微球粒径为1.8μm.

Research on preparation of monodisperse and narrow distribution PMMA microspheres

The monodisperse micro grade poly （methyl methacrylate） microspheres obtained by dispersion polymerization. The PMMA microspheres were characterized by Fourier-transform infrared （FT-IR）, Field emission scanning electron microscopy （SEM） , Laser particle size analysis（SPAN）. The optimum reaction conditions for synthesizing monodisperse, micron-sized PMMA microspheres had been found through the studies of the effects of reaction time, monomer concentration, stabilizer concentration and initiator concentration on the size and size distribution of particles. The main factors which effeeted diameter of PMMA mierospheres were monomer and stabilizer concentration. When stabilizer concentration increased, initiator concentration decreased, the diametter decreased and the distribution narrowed. Mierosphere particle size of 1. 8 μm was obtained by the optimal conditions with the PVP content of 1.5%, the AIBN content of 1%, the monomer content of 10%, the methanol amount of 60%, constant temperature on 75 ℃, the reaction time of 6 h.