Jayakrishnan A, Thanoo B C
Polymer Chemistry Division, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Trivandrum, India.
J Biomed Mater Res. 1990 Jul;24(7):913-27. doi: 10.1002/jbm.820240709.
Spherical, highly porous beads of poly(2-hydroxyethyl methacrylate) (PHEMA) cross-linked with ethylene glycol dimethacrylate (EGDM) were prepared by suspension polymerization of HEMA in concentrated NaCl solutions in presence of toluene, poly(methyl methacrylate) (PMMA) in toluene, and poly(tetramethylene glycol) (PTMG). Magnesium hydroxide prepared in situ in the dispersion medium gave the best stabilization effect for the monomer droplets. In the presence of PTMG, beads having nearly 1.0 mm in diameter could be prepared, while toluene alone as the diluent produced beads of very small size. Removal of PMMA or PTMG from the beads after polymerization using suitable solvents gave rise to highly porous PHEMA microspsheres. Polymerization in the presence of PTMG produced microspsheres with better spherical geometry as compared to those generated in the presence of PMMA. The effect of various factors such as NaCl concentration, concentration of Mg(OH)2, and the concentration of PMMA or PTMG in the monomer phase on the stability of the suspension and the particle size distribution was investigated.
通过在甲苯、甲苯中的聚甲基丙烯酸甲酯（PMMA）和聚四亚甲基二醇（PTMG）存在下，于浓氯化钠溶液中悬浮聚合甲基丙烯酸2-羟乙酯（HEMA），制备了与乙二醇二甲基丙烯酸酯（EGDM）交联的聚（甲基丙烯酸2-羟乙酯）（PHEMA）球形高孔隙率珠粒。在分散介质中原位制备的氢氧化镁对单体液滴具有最佳的稳定效果。在PTMG存在下，可以制备直径接近1.0毫米的珠粒，而单独使用甲苯作为稀释剂则会产生非常小尺寸的珠粒。聚合后使用合适的溶剂从珠粒中除去PMMA或PTMG，得到了高孔隙率的PHEMA微球。与在PMMA存在下生成的微球相比，在PTMG存在下聚合产生的微球具有更好的球形几何形状。研究了各种因素，如NaCl浓度、Mg(OH)₂浓度以及单体相中PMMA或PTMG的浓度对悬浮液稳定性和粒径分布的影响。
