Preparation and Characterization of Emulsifier-free Cationic MMA/HEMA Copolymer Latex Particle

Using 2,2′-azobis isobutyramidine dihydrochloride(AIBA) as the initiator, hydrophilic monomer methylmethacrylate(MMA) and methacrylicacid 2-hydroyethylester(HEMA) copolymerized under microwave irradiation. The particles were characterized by using Transmission electron microscopy(TEM), Infrared spectroscopy(IR) and Differential thermal analysis(DTA). The results indicated that monodisperse copolymer particles were synthesized and their surfaces were clear. Increasing the concentration of HEMA, the particle size was decreased and then increased. The rate of copolymerization was very fast. All reactions finished within 20 min, which was the advantage of microwave irradiation. The electrolyte-resistance of latex stability was determined by critical coagulation concentration of electrolyte. The result was that the particles were emulsifier-free cationic particles and the latex stability was much better with the increase of the concentration of HEMA.