Preparation of Monodisperse PMMA Microspheres by Emulsifier-free Emulsion Polymerization with Cu~(2+) System

Monodisperse poly(methyl methacrylate)(PMMA)microspheres were successfully prepared through emulsifier-free emulsion polymerization with Cu2+system,using methyl methacrylate(MMA)as the monomers,and potassium persulfate(KPS)as the initiator.The structural and surface morphological properties were investigated by Fourier transform infrared spectroscopy(FTIR)and scanning electron microscopy(SEM).The effects of the reaction parameters,such as the monomer concentration in the systems,the initiator dosage,the Cu2+concentration and the adding time of Cu2+on the monomer conversion,surface morphology,the particle size and the size distribution were systematically studied.The results show that the size of PMMA microspheres is not uniform,and it leads to a wider size distribution of PMMA microspheres while adding Cu2+at the beginning of the reaction.It is also found,however,that the monodisperse PMMA microspheres with a uniform particle size about 300 nm are obtained by adding Cu2+after 2hof polymerization.