Zhongyu Fu

Preparation of monodisperse, sub-micrometer polymer particles by one-step emulsion polymerization under particle coagulation

The particle coagulation technology in emulsion polymerization is a novel and facile approach to prepare large-scale, narrowly dispersed latex particles. However, the formation of narrowly dispersed latex particles under particle coagulation at a high zeta potential is surprising. To elucidate this observation, a detailed investigation on the relationship between particle coagulation and particle size distribution was carried out. Unlike the conventional emulsion polymerization, a rapid decrease in the particle number and an increase in the particle size were clearly observed during the polymerization. The results confirm the occurrence of particle coagulation. The width of zeta potential and particle size distribution also decreased with particle coagulation, resulting in large-size, narrowly dispersed latex particles. These phenomena were explained by the competitive growth mechanism.

Facile synthesis of large sized and monodispersed polymer particles using particle coagulation mechanism: an overview

Highly uniform polymer latex particles with controlled particle size have been widely applied in many fields such as nanotechnology, drug delivery, biomedical separation, and material templates. Since the particle size plays a critical role in determining the application fields, various technologies such as two-stage swelling method and dynamic swelling method have been used to control the particle size in the polymerization process. However, these methods usually need a multi-step polymerization reaction and long reaction time. This review focuses on a method of controlling particle size, that is, particle coagulation technology. Particle coagulation technology can be used to produce large sized, monodispersed polymer particles by soap-free emulsion polymerization, macroemulsion polymerization, and dispersion polymerization. In this review article, an overview of the concept of particle coagulation is given, followed by the description of the particle coagulation process in different polymerization systems. Some representative publications about particle coagulation were also reviewed, especially the effect of reaction parameters on the particle coagulation extent and time. Finally, the relationship between the particle coagulation and particle size distribution is reviewed extensively.

Effect of Polymer Characteristics on Particle Formation and Growth in Batch Emulsion Polymerization

This article is an extensive investigation on particle coagulation growth in emulsion polymerization proposed by our team (Colloid and Polymer Science, 2013, 291, 2385–2398). Monodispersed, large-scale, high-solid content poly (butyl acrylate) latex was obtained by varying the reaction procedures in previous studies. However, the present method, which could be used in other monomer systems such as styrene, methyl methacrylate, or the copolymerization of different monomers, has not been reported to date. In this article, the particle formation and growth behaviors of different monomer compositions were investigated in regard to the range of application and to clarify the effect of monomer characteristics on particle coagulation. Experimental results indicated that polymer characters such as hydrophilicity play an important role in particle coagulation, which was increased with increasing monomer hydrophilicity. Moreover, particle coagulation could improve reaction system stability and enhance the likelihood of obtaining a high solid content. The optimal systems for styrene, methyl methacrylate, and butyl acrylate were 40, 50, and 60 wt%, respectively, due to variation in monomer hydrophilicity. GRAPHICAL ABSTRACT