Microwave assisted preparation of monodisperse polymeric microspheres and its morphologies and kinetics

The emulsifier-free emulsion polymerization of N-hydroxymethyl acrylamide (NMA), methyl methacrylate (MMA) and styrene (St) was successfully carried out under microwave irradiation, and monodisperse polymeric microspheres were prepared. The experimental results show that the emulsifier-free emulsion polymerization under microwave irradiation has more rapid reaction rate, higher conversion and shorter induction time than the copolymerization with conventional heating. The apparent activation energies are 61.04 and 83.75 kJ/mol, respectively; the microspheres have spherical morphology, and the microspheres prepared by emulsifier-free emulsion polymerization under microwave irradiation are smaller, more uniform than those obtained with conventional heating.