PREPARATION OF MICROSPHERES BY RADIATION-INDUCED POLYMERIZATION .1. MECHANISM FOR THE FORMATION OF MONODISPERSE POLY(DIETHYLENE GLYCOL DIMETHACRYLATE) MICROSPHERES

Monodisperse microspheres of poly(diethylene glycol dimethacrylate) with diameters in the size range 0.4-4.8-mu-m were prepared by the radiation-induced polymerization. Effects of solvent viscosity and monomer solubility were investigated for various kinds of solvents. The number of the nuclei, produced in the early stage of the polymerization, was found to be constant during the remainder of the polymerization. The nuclei grow to be monodisperse polymer particles without aggregation. This is attributed to the low mobility of the growing polymer particles.