以聚苯乙烯为壁材的聚硫橡胶微胶囊制备与表征

Preparation and Characterization of Polystyrene-shelled Polysulfide Rubber Microcapsules

聚硫橡胶特殊的分子结构使其具有优异的密封、防腐、力学性能与粘接能力,但使用过程中暴露出的流动性强、活性期短、装配工艺繁琐等问题,极大地限制了其装配水平与工业应用.为解决上述问题,本工作以液体聚硫橡胶为芯材、聚苯乙烯为壁材,通过溶剂蒸发法研制出尺寸均匀、表面光滑的微胶囊,使黏度较大的聚硫橡胶实现从液体到固体的转变.此外,根据壁材在液体聚硫橡胶液滴表面吸附机理、演化过程及固化机制,考察乳化体系、反应温度、搅拌速率、芯壁质量比等条件对微胶囊形貌与分布的影响,实现微胶囊尺寸与成分的可调控性.实验结果表明,以PVA和NaOA的混合溶液作为乳液体系可获得均匀程度更好的微胶囊,该乳化条件不仅能显著提升微胶囊中聚硫橡胶的含量(芯材含量可增至60 wt%),而且可大幅降低微胶囊的尺寸,平均粒径可低至2.23μm.以上研究为新一代微胶囊基密封剂的工程化应用奠定良好基础,在密封剂装配自动化领域具有研发意义和应用价值.

The special molecular structure of polysulfide rubber made it have excellent sealing,anticorrosion,mechanical properties and bonding ability.However,the problems exposed in the use process,such as strong fluidity,short active period and complicated assembly process,greatly limited the assembly level and industrial application of polysulfide rubber.In order to solve the problems above,in this work,liquid polysulfide rubber was used as the core material and polystyrene as the shell material.Microcapsules with uniform size and smooth surface were prepared by solvent evaporation method,so that the viscous polysulfide rubber can be transformed from liquid to solid.According to the adsorption mechanism,evolution process and curing mechanism of wall materials on the surface of polysulfide rubber droplets,the effects of emulsion system conditions,reaction temperature,stirring rate and core-wall mass ratio on the morphology and distribution of microcapsules were investigated to realize the adjustability of microcapsule size and composition.The experimental results showed that the microcapsules with better uniformity can be obtained by using the mixed solution of PVA and NaOA as the emulsion system.This emulsification condition can not only significantly increase the content of polysulfide rubber in the microcapsules(the core content can be increased to 60 wt%),but also greatly reduce the size of the microcapsules,and the average particle size can be as low as 2.23μm.The above research laid a good foundation for the engineering application of the new generation microcapsule-based sealant,which was of great significance and application value to the assembly automation of sealants.