Study on the Formation and Variation of Monodisperse Nano-sized Polystyrene Beads by Suspension Polymerization with Hydrophilic Polymer as a Stabilizer

摘要

We found that monodisperse polymeric particles with diameters in the range of a few hundred nanometers can be prepared by suspension polymerization with water as its dispersing medium. The ratio between monomer and water was selected to be 10 and polymerization conducted at 70°C. Azobisisobutyronitrile was employed as an initiator and a polymer with strong hydrophilic end groups as a stabilizer. Particle diameter was found to vary between 100 and 200 nm depending on reaction conditions. An increase in monomer concentration contributes to an increase in particle diameter and deviation from monodispersity. The weight average molecular weight of polystyrene beads was found to be dependent on the reaction temperature and initiator concentration. Glass transition was determined to be between 100 and 105°C.