Synthesis of polystyrene suspensions in the conditions for obtaining an emulsifier at the interface

Abstract

Emulsion polymerization of styrene was investigated using salts of stearic and lauric acids with cations of different metals (K+, Li+, Ba2+, Ca2+, Zn2+) as emulsifiers. Emulsifier was injected in two ways: using prepared salts introduced into the aqueous phase (1) or salts formed at the monomer/water phase boundary at the moment of polymerization (2). The second method of the emulsifier introduction proved to be more effective. In this case, there was a significant reduction in the interfacial tension promoting the intense microemulsification of a monomer. The kinetics of the polymerization was studied by the method of dilatometry. Interfacial tension at the monomer/water phase boundary was measured by stalagmometric method. Sizes of the particles of polymer suspensions were determined by electrophoretic light scattering.

It has been shown that the polystyrene suspension having a narrow particle size distribution and a diameter of 0.2 microns can be obtained using 0.5% of lithium stearate as an emulsifier in the conditions of its synthesis at the phase boundary, with a volume ratio of the monomer/aqueous phase 1:10 and the concentration of the initiator 1%. Monodispersed granules of polystyrene suspensions with a diameter of 0.2 micron are highly promising as carriers of protein cell to create diagnostic kits for various diseases.