Nano-Ga/PMMA Composites Synthesized Ultrasonically In Situ In Emulsion Polymerization

Preparation and dispersion technology of nano-Ga particles, preparation and characterization technology of polymer nanoparticles and of nano-Ga/polymer composite particles were mainly studied by ultrasonic wave in this paper. The forming mechanism of nano-Ga/polymer composite particles was initially researched.The homodispersing nano-Ga particles were prepared by ultrasonic crushing method with plasmosan(PVP) used as dispersing and stabilizing agent. And the effects of ultrasonic time and concentration of PVP on stability of dispersing system were studied. The results suggested that nano-Ga particles that were rabdoid with 40-50nm were made by ultrasonic after 30 minutes.The special effects of ultrasonic wave including dispersion, emulsification, initiation and so on, make emulsion polymerization of metheyl methacrylate(MMA) into poly(metheyl methacrylate) nanoparticles. Effects of kinds of factors on conversion rate of MMA monomer and molecular weight of polymer were studied in detail. The size of PMMA emulsion particles was characterized by means of TEM, and the results showed that the size of the particles was about 45-60nm;the distribution of the PMMA emulsion particles from the results of Laser Graininess testing was about normal distribution and the number percent of paticle between 35nm and 70nm was 86% in number average distribution. The microstructure of PMMA was characterized by FT-IR and thermal performance by TG-DTA.The nano-Ga/poly(metheyl methacrylate) composite particles were formed by ultrasonic wave. The effect of nano-Ga paticles on conversion rate of MMA and the stability of polymer eumulsion were studied. The microstructure of composite particles were characterized by TEM, FT-IR, TG-DTA and XPS. The experimental results showed that nano-Ga particles were coated by PMMA and the composite particles with 60-100nm had typical core/shell structure, and the microlevel recombination was realized because there were physical package and chemical action between metal nanoparticles and polymer layer. The forming mechanism of nano-Ga/PMMA composite particles was discussed in the paper.