Abstract: In the emulsion polymerization process, organic polymers carrying functional groups are involved in the elaboration of the hybrid latex in order to improve the chemical bonding between the organic and inorganic components.The organic-inorganic hybrid nanoparticles were synthesized by using 3-trimethoxysilyl propyl methacrylate (MPS) in the authors’ work.In the emulsion polymerization process of MPS and styrene, SiOR groups are hydrolyzed and condensed simultaneously with free radical polymerization when they contact with water.The emulsion stability and the organic-inorganic hybrid microstructures are largely dependent on the hydrolysis-condensation rates, and the competition between free radical polymerization rate and hydrolysis-condensation rate determines the final microstructure of the hybrid materials.Hydrolysis-condensation rate coefficients were measured at different pH values by ²⁹Si liquid-state NMR.It was found that the hydrolysis rate coefficient was the lowest when pH=7.0, and increased significantly in both acidic and basic conditions, while the condensation rate coefficient was the lowest when pH=4.0.An equation was presented to estimate the hydrolysis and condensation rate coefficients at different pH values.

摘要： 在甲基丙烯酸-3-三甲氧基硅丙酯（MPS）和苯乙烯的乳液共聚合反应中，MPS与水接触时其SiOR基团会发生水解缩合反应，其反应速率对乳液体系的稳定有很大的影响，而且所得产物的杂化结构也由SiOR基团的水解缩合反应速率决定.通过²⁹Si核磁共振谱，测定了不同pH值下MPS的水解-缩合速率常数.发现MPS的水解速率常数在pH=7时最小，无论是在酸性条件还是碱性条件都使其迅速增大.而MPS的缩合速率常数则在pH=4时达到最小，而在相对较高pH值和更低的pH值时，其缩合速率常数也都迅速增大.并得到了不同pH值时水解-缩合速率常数估算式.为进一步研究MPS乳液聚合的过程机理、反应过程动力学模型的求解以及通过模型对反应结果的预测提供了依据和基础数据.