单分散、大粒径聚苯乙烯微球的制备

PREPARATION OF MONODISPERSE POLYSTYRENE MICROSPHERES WITH LARGE SIZE

以聚乙烯基吡咯烷酮为分散剂、偶氮二异丁腈为引发剂、醇／水混合物为分散介质进行了苯乙烯的分散聚合，讨论了初始单体浓度、分散剂用量、引发剂浓度、分散介质组成和反应温度等反应条件对所得聚合物颗粒直径和直径分布的影响．通过大量的试验，筛选出了较为理想的分散聚合的条件及配方，制备出了粒径为４８μｍ的单分散聚苯乙烯微球．然后，以分散聚合所制得的聚合物颗粒为种子，用动力学溶胀法制成了粒径增大近四倍的单分散、大粒径聚苯乙烯微球。

dispersion polymerization of styrene was carried out in ethanol/water medium in the presense of polyvinylpyrrolidone using azobisisobutyronitrile as initiator. The effects of initial mononer concentration, stabilizer concentration, initiator concentration, medium composition and reaction temperature on the size and size distribution of polymer particles were investigated through condition experiments. An ideal recipe was found out from which monodisperse polymer particles of 4 8 μm in diameter were accessible. Then the seed particles of polystyrene produced by dispersion polymerization were further swollen to about four times in diameter by means of dymanic swelling method. And the effects of water adding rate and the amount of dispersion agent added in the swollen system on swelling process were studied. Finally, the large size monodisperse polymer microspheres were obtained by polymerizing the monomen swollen particles.