中文摘要：

以三羟甲基丙烷三丙烯酸酯（TMPTA）为交联剂,甲基丙烯酸甲酯（MMA）为共聚单体,偶氮二异丁腈为自由基引发剂,以乙醇或乙醇-水混合物作溶剂,在2 wt%的单体浓度下通过沉淀聚合制备了交联聚合物微球.探究了聚合时间、混合溶剂的含水量以及交联剂TMPTA用量对聚合过程及聚合产物的影响.结果表明,增加TMPTA用量可提高单体转化率和微球产率;所得微球的粒径则随着TMPTA用量的增加而减小.TMPTA用量占单体总量40 wt%至80 wt%,反应时间不少于6 h时可制得高度单分散聚合物微球,产率达到80%以上.在反应介质中加入水可明显提高单体转化率和微球产率,当混合溶剂中水的体积分数为35%时,仍可制得高度单分散聚合物微球,产率可达94%;但当混合溶剂中水的体积分数达40 vol%时,所得微球的多分散系数增大.

英文摘要：

Uniform polymer microspheres of diameters between 1 p,m and 2 μm were prepared through precipitation polymerization of trihydroxymethyl propane triacrylate （TMPTA） and methyl methacrylate （MMA） at 2 wt% of monomer concentration in ethanol or in its mixture with water. 2,2-Azobis-isobutyronitrile was used as the free radical initiator. Effects of polymerization conditions, including polymerization time, amount of the cross-linker monomer TMPTA and water content in the mixed solvent, on the polymerization process and the size and the uniformity of the microspheres were studied. The results indicated that, during polymerization,a large amount of polymer was present as oligomers of low molecular ＇weight and remained dissolved in the solvent,which made the monomer conversion and the yield of the microspheres increase not at the same time：monomer conversion showed a fast increase at start of the polymerization, leading to a high amount of oligomers with quite low amount of polymer particles. At a later stage of polymerization （ 〉 2 h）, when the monomer conversion reached to its highest value in the polymerization and became almost constant, the yield of the microspheres was keeping to increase at a much higher rate than the monomer conversion, owing to a direct adsorption of the oligomers by the microspheres or/and the continuous polymerization of the oligomers with the double bonds on the surface of the microspheres. Monomer conversion and microsphere yield were increased with increasing the TMPTA amount and the water proportion in the binary solvent; whereas the size of microspheres was decreased on the same time. While polymer microspheres were well formed for TMPTA-MMA polymerization with TMPTA/MMA mass ratio of 6/4, providing that the water amount in the solvent was controlled at 42 vol% or lower in the mixed solvent, highly uniform microspheres （Dw/Dn≤ 1.01 ） were obtained only when the water amount was kept between 30 vol% and 40 vol%. With the water amount in ethanol-water fixed at 35 v