Preparation of Monodisperse Polymer Particle via an in situ charge neutralization-controlled particle coagulation mechanism in macroemulsion polymerization
Preparation of Monodisperse Polymer Particle via an in situ charge neutralization-controlled particle coagulation mechanism in macroemulsion polymerization
复制标题
粗乳液聚合中通过原位电荷中和控制颗粒凝聚机制制备单分散聚合物颗粒
DOI：
10.1016/j.colsurfa.2019.124345
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Xiangchi Liu
中科院分区：
文献类型：
--
作者：
Yiye Wang;Xueyan Luo;Ye Han;Baijun Liu;Yiwei Hu;Xiangchi Liu
研究了以十二烷基硫酸钠为阴离子表面活性剂，在阳离子引发剂2，2′-偶氮二（2-甲基丙脒）二盐酸盐（AIBA）和2，2 ′-偶氮二（N，N′-二亚甲基异丁脒）二盐酸盐（ADIBA）存在下的苯乙烯乳液聚合。本文提出了原位电荷中和的一种解释，并讨论了原位电荷中和对最终聚合物颗粒粒径分布的影响。引发剂分解产生的阳离子自由基的电荷屏蔽了吸附在颗粒表面的表面活性剂分子的阴离子电荷，并在颗粒形成早期诱导颗粒凝聚。由于原位电荷中和作用的发生，引发剂自由基的胶束捕获速率提高，引发剂自由基的粒子数减少。因此，颗粒成核期缩短，并且使用这种简单的乳液聚合方法制备直径为~200 - 300 nm的单分散聚合物颗粒。此外，引发剂AIBA在不同pH条件下的水解用于控制粒度和稳定性。与传统的乳液聚合理论相比，原位电荷中和作用下的乳液聚合具有独特的动力学性质。
Styrene emulsion polymerizations using sodium dodecyl sulfate as an anionic surfactant and in the presence of cationic initiators 2, 2′- Azobis (2-methylpropionamidine) dihydrochloride (AIBA) and 2,2′-azobis(N,N′-dimethyleneisobutyramidine) dihydrochloride (ADIBA) were studied. In this work, an explanation forin situcharge neutralization is proposed, and the effect ofin situcharge neutralization on the particle size distribution of the ultimate polymer particles is discussed. Charges of cationic radicals from initiator decomposition shield the anionic charges of surfactant molecules adsorbed on the particle surface and induce particle coagulation during the early particle formation period. As the occurrence ofin situcharge neutralization, the particle number decreases and the rate of micelle capture for the initiator radical is enhanced. Thus, the particle nucleation period is shortened, and monodisperse polymer particles with a diameter of ~200−300 nm are prepared using this simple emulsion polymerization process. In addition, hydrolysis of the initiator AIBA at different pH conditions is used to control particle size and stability. Compared to conventional emulsion polymerization theories, the emulsion polymerization in the presence ofin situcharge neutralization presents unique kinetics.