SiO_2大分子单体的合成

Preparation of Silica Macromonomer

采用两步法将可聚合的乙烯基单体键接到S iO2纳米粒子表面合成大分子单体。用过量的甲苯-2,4-二异氰酸酯(TD I)对S iO2粒子表面进行化学修饰合成出表面带有高反应活性—NCO基团的功能化S iO2粒子(S iO2-TD I),再利用S iO2-TD I与丙烯酸羟丙酯(HPA)反应将碳-碳双键键接到S iO2粒子表面合成出大分子单体。考察了反应条件对TD I与S iO2反应的影响。此外,利用红外光谱、热失重和透射电子显微镜测试技术对大分子单体进行表征。结果表明,S iO2大分子单体能均匀地分散在甲苯溶液中,没有发生明显团聚。

A two-stage process was developed to synthesize the silica-based maeromonomer through the surface-modification of silica with polymerizable vinyl groups. The silica surface was first treated with excess toluene-2,4-diisocynate（TDI）, after which the residual isocyanate groups were converted into polymerizable vinyl groups by reaction of the above mixture with hydroxypropylacrylate（HPA）. The main effecting factors on the reaction of silica with TDI were studied by determining the reaction extent of hydroxyl groups at the surface of silica particles. FTIR spectroscopy and TG were employed to characterize the macromonomer. TEM images showed that the silica particles remained unaggregated after surface modification.