Composite Polymer Nanoparticles via Transitional Phase Inversion Emulsification and Polymerisation

Summary: A new route was employed to produce composite polymer nanoparticles. First, a model polymer (a low molecular-weight polyisobutene) was dissolved in a model monomer (styrene) and then the solution was emulsified in water containing a pair of nonionic surfactants via a transitional phase inversion route. After phase inversion, which produced an oil-in-water miniemulsion, polymerisation of the vinyl monomer gave composite polymer particles. Low temperature emulsification was not practical because the inverted oil-in-water emulsions reinverted to water-in-oil emulsions upon raising the temperature to the reaction temperature. Miniemulsions prepared at the reaction temperature with low monomer content in the oil phase showed good stabilty in the course of polymerisation and produced latexes with a particle size similar to the size of drops in the initial miniemulsions.     

On the evolution of particle size average and size distribution in suspension polymerization processes

The dispersion of methyl methacrylate (MMA) and its suspension polymerization were used as models to elaborate the evolution of particle size average and size distribution in the course of suspension polymerization. The underlying mechanisms for the occurrence of the dynamic and static steady states in the population of drops were defined and their effects on the evolution of drop/particle size average and size distributions were examined. The characteristic intervals of suspension polymerizations (transition, steady-state, growth, and identification) were elaborated. The formation of satellite droplets and their evolution in the course of polymerization were also discussed.