Preparation of Monodisperse Polymer Particle via an in situ charge neutralization-controlled particle coagulation mechanism in macroemulsion polymerization

Publication date: Available online 14 December 2019Source: Colloids and Surfaces A: Physicochemical and Engineering AspectsAuthor(s): Yiye Wang, Xueyan Luo, Ye Han, Baijun Liu, Yiwei Hu, Xiangchi LiuGraphical AbstractSchematic representation of in situ charge neutralization in emulsion polymerization of styrene controlled by pH conditions using AIBA as the initiator.AbstractStyrene 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 for in situ charge neutralization is proposed, and the effect of in situ charge 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 of in situ charge 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 ...
Source: Colloids and Surfaces A: Physicochemical and Engineering Aspects - Category: Chemistry Source Type: research
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