Formation of monodisperse polyacrylamide particles by radiation-induced dispersion polymerization: particle size and size distribution.

Polyacrylamide microparticles were directly produced by radiation-induced dispersion polymerization in aqueous alcohol media using poly(N-vinylpyrrolidone) as a steric stabilizer at room temperature. The hydrodynamic diameter of a polymer particle and its distribution were measured on a dynamic laser light-scattering spectrometer. This method takes advantages of the specialties of radiation induction, and highly uniform polymer microspheres were obtained with high conversion. The number of the particle produced in the early stage of the polymerization was found to be constant during the remainder of the polymerization. The effects of various polymerization parameters, such as absorbed dose rate, monomer concentration, stabilizer content, medium polarity, and polymerization temperature on the particle size and size distribution were systematically investigated.