A study on the nucleation mechanisms under critical micelle concentration (CMC) in emulsion polymerization of methyl methacrylate (MMA)

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• 作者：Yanping He ; Yanlin Sun ; Linhua Zhu ; Xiaoqin Xiao ; Bingwen Xu…
• 关键词：Emulsion polymerization ; Flocculation nucleation ; Methyl methacrylate ; Micellar nucleation ; Controllable particle number
• 刊名：Iranian Polymer Journal
• 出版年：2015
• 出版时间：November 2015
• 年：2015
• 卷：24
• 期：11
• 页码：935-944
• 全文大小：2,018 KB
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• 作者单位：Yanping He (1)
  Yanlin Sun (1)
  Linhua Zhu (1)
  Xiaoqin Xiao (1)
  Bingwen Xu (1)
  Tian Si (1)
  Hong Wang (2)
  
  1. School of Chemical Engineering, Kunming University of Science and Technology, Chenggong Campus, Kunming, Yunan, 650504, China
  2. Faculty of Science, Kunming University of Science and Technology, Chenggong Campus, Kunming, Yunan, 650504, China
  
• 刊物主题：Polymer Sciences; Ceramics, Glass, Composites, Natural Methods;
• 出版者：Springer Berlin Heidelberg
• ISSN：1735-5265

文摘

In this study, formulation of latex with methyl methacrylate (MMA) as a function of surfactant concentration ([S]) under critical micelle concentration (CMC) was investigated to explore the nucleation mechanism and the key to control the particle number (N _p) of latex in emulsion polymerization. Influences of surfactant concentration [S] on the conversion of monomer, particle size (PS), N _p, and surfactant surface coverage (θ) were studied, as well. Flocculation nucleation was considered as the main mechanism to generate particle nuclei when [S] was much less than CMC. The nucleation mechanism experienced an evolution of a flocculation nucleation-dominated region ([S] < 3.3 mmol L−1) to a micellar nucleation-dominated region ([S] > 3.3 mmol L−1). The contribution ratio of the flocculation nucleation was 86 % compared with the micellar nucleation. The particle number (N _p) was found to be controlled by the combination of micellar and flocculation nucleation-dominated regions under CMC, and the regulation range was about 1–6. The results can be used to guide the preparation of a bimodal high solid content (HSC) latex by creating a population of small particles in the presence of an initial population of larger ones in a controllable way. In this way, a controllable amount of large latex particles were prepared using a high emulsifier concentration, at first, and then the second population of small particles was formulated by secondary nucleation at a proper time through controlling surfactant concentration at a low level, followed by the growth of the two groups of the particles, and then the bimodal HSC latex can be prepared at low viscosity.