Kinetic Factors in Miniemulsion Polymerization

细乳液聚合中的动力学因素

• 批准号: 8907600
• 负责人: Mohamed El-Aasser
• 金额: $ 24.34万
• 依托单位: Lehigh University
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-09-01 至 1993-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8907600&HistoricalAwards=false
• 关键词: Kinetic; Factors; Miniemulsion; Polymerization

Emulsion polymerization is used in industry for the production of polymer latexes for applications such as coatings, binders, adhesives, paints and foams. In this process, polymer particles are created in the presence of stabilizing emulsifiers with diffusion of monomer from large droplets (greater than approximately 10 microns in diameter) to the growing particles which are approximately 0.1 to 0.4 microns in diameter. An alternative to emulsion polymerization is miniemulsion polymerization in which the monomer phase is first dispersed into the aqueous phase in the form of small and stable droplets in the size range of approximately 0.05 to 0.4 microns in diameter through the use of a mixed emulsifier system. These miniemulsions are formed by the addition of a co-surfactant (for example hexadecane or cetyl alcohol) to the usual emulsion polymerization recipe, typically containing sodium dodecyl sulfate as surfactant. Initiation an polymerization then take place in the monomer droplets and the product polymer particles are approximately the same size as the initial monomer droplets. To gain a more fundamental understanding of the mechanisms involved in miniemulsion polymerizations, the PIs plan to: 1. Determine the effect of the composition of the particle/water interface and the monomer/polymer particle on the entry and exit rates of free radicals to and from the droplets/particles. 2. Test the existing methodologies for the determination of the entry and exit rate coefficients which have a direct bearing on the mechanisms of this heterogeneous polymerization. 3. Determine the relative importance of droplet/droplet, particle/droplet, and particle/particle instabilities and their influence on miniemulsion polymerization. 4. Examine the effect of the breadth in the particle/droplet size distributions through simulations of the miniemulsion polymerization kinetics, hereby approaching a more realistic description of an actual system.

乳液聚合在工业上用于生产 聚合物胶乳的应用，如涂料，粘合剂， 粘合剂、涂料和泡沫。 在这个过程中，聚合物 粒子是在稳定剂的存在下产生的 单体从大液滴扩散的乳化剂 （直径大于约10微米） 生长的颗粒约为0.1至0.4微米 直径。 乳液聚合的替代方案是 细乳液聚合，其中单体相是 首先分散到水相的形式小 和尺寸范围为约0.05至 0.4通过使用混合乳化剂， 系统 这些细乳液是通过添加一种 助表面活性剂（例如十六烷或鲸蜡醇）添加到所述表面活性剂中。 通常的乳液聚合配方，通常包含 十二烷基硫酸钠作为表面活性剂。 启动和 然后在单体液滴中发生聚合， 产物聚合物颗粒的尺寸与 初始单体液滴。 对机制有更根本的了解 参与细乳液聚合，PI计划： 1. 确定组合物的影响， 粒子/水界面和单体/聚合物 自由粒子的进入和退出速率 自由基进出液滴/颗粒。 2. 测试现有的确定方法 的进入和退出率系数，其中有 直接影响到这一机制， 多相聚合 3. 确定液滴/液滴的相对重要性， 粒子/液滴和粒子/粒子 不稳定性及其对细乳液的影响 聚合法 4. 检查宽度在 颗粒/液滴尺寸分布， 细乳液聚合模拟 动力学，从而接近一个更现实的 描述一个实际的系统。