Microemulsion Polymerization of Styrene: The Effect of Salt and Structure
Microemulsion Polymerization of Styrene: The Effect of Salt and Structure
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苯乙烯微乳液聚合：盐和结构的影响
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
J. E. Puig
中科院分区：
文献类型：
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作者：
A. Full;E. Kaler;J. Arellano;J. E. Puig
研究了苯乙烯在阳离子表面活性剂十二烷基三甲基溴化铵或十二烷基三甲基氯化铵制成的水包油型微乳液中的聚合反应，考察了无机电解质（KBr、KCl或K2SO4）浓度对聚合反应的影响。所得微胶乳是稳定的，但随着电解质浓度的增加，平均半径和聚合物分子量都降低。电解质的存在减慢了聚合速率并减少了最终转化率，如随后的重量分析法、渗透率测定法和量热法所示。这两个粒子的半径，由准弹性光散射，和分子量，仅显示有限的增长，苯乙烯转化率的增加，这表明连续成核的胶乳颗粒和终止链转移到单体。小角中子散射（SANS）的未稀释的母体和聚合的微乳液表明，单峰人口的溶胀胶束演变成双峰人口的空胶束共存的大聚合物颗粒。结构细节
The polymerization of styrene in oil-in-water microemulsions made with the cationic surfactants dodecyltrimethylammonium bromide or chloride is studied as a function of inorganic electrolyte (KBr, KCl, or K2SO4) concentration. The resulting microlatex is stable, but as the electrolyte concentration increases, both the average radius and the polymer molecular weight decrease. The presence of electrolyte slows the polymerization rate and diminishes final conversion as followed by gravimetry, dilatometry, and calorimetry. Both particle radius, determined by quasielastic light scattering, and molecular weight show only limited growth as styrene conversion increases, suggesting continuous nucleation of latex particles and termination by chain transfer to monomer. Small-angle neutron scattering (SANS) of undiluted parent and polymerized microemulsions shows that a unimodal population of swollen micelles evolves into a bimodal population of empty micelles coexisting with large polymer particles. Structural detai...