Preparation of Monodisperse, Micron-Sized Polystyrene Particles with an Amphoteric Initiator in Soapfree Polymerization.

Synthesis of micron-sized polymeric particles in soap-free emulsion polymerization using oil-soluble initiators and electrolytes

“…On the other hand, soap-free emulsion polymerization, which has been used for the preparation of submicron-sized particles [6], is gentle on the environment because the polymerization is performed in water without surfactants. However, in recent research, micron-sized polymeric particles were synthesized using 2,2′-azobis [N-(2-carboxyethyl)-2-2-methylpropionamidine] hydrate (VA057) as a water-soluble initiator, even in soap-free emulsion polymerization [7][8][9].…”

Synthesis of highly monodisperse polystyrene microspheres via dispersion polymerization using an amphoteric initiator

“…Recently, the micron-sized monodisperse PS and PMMA particles have been synthesized using amphoteric initiators via emulsion polymerization in aqueous media by means of successive addition of monomer or by controlling pH or ionic strength of the system [12][13][14][15][16][17]. Since amphoteric initiators bear both positively and negatively ionizable groups, the polymerization characteristics and the properties of the particles produced in this way are sensitively affected by the pH and ionic strength of the reaction system [12].…”

Soap-free synthesis for producing highly monodisperse, micrometer-sized polystyrene particles up to 6 μm

“…Since the dissociation degree of the ionizable groups depends on the pH, the electric surface potential of the particles can be varied with a pH change, which controls particle coagulation, eventually affecting final particle sizes. A previous report verified that highly monodisperse, micrometer-sized polymer particles could be produced by this method [25]. A simple method for further enlarging the sizes of polymer particles is monomer addition during the polymerization.…”