Abstract Seed dispersion polymerization of methyl methacrylate (MMA) in the presence of monodisperse PMMA particles was carried out in an aqueous methanol using poly(methacrylic acid) stabilizer. The polymerization using 2. 5 μ. m-sized seed particles gave monodisperse PMMA particles in the diameter up to 4. 9 μm. The solvent composition and monomer concentration greatly affected the polymerization behavior. Under appropriate conditions, monodisperse PMMA particles in the diameter up to 8. 9 μ, m was prepared from 4. 6 μm-sized seed particles. The seed dispersion polymerization of styrene in the presence of the seed particles produced monodisperse PMMA-polystyrene particles in the micron range. The particles were supposed to have a structure consisting of PMMA-core and polystyrene-shell from ESCA analysis. 相似文献
Polystyrene (PS) colloidal particles were prepared in aqueous solution by a quick emulsifier-free emulsion polymerization (EFEP) method. The scanning electron microscopy (SEM) images indicate that the as-synthesized particles have good sphericity and uniform size (dispersion coefficient Cv is less than 5%). The monodisperse PS microspheres with different diameter were obtained easily by varying the monomer concentration. The atomic force microscopy (AFM) images show that the PS microspheres were self-assembled into three-dimensional ordered structure on micas by dropping-casting method. The self-assembly method is simple and quick. Based on the experimental results, a possible self-assembly mechanism was proposed. 相似文献
Crosslinked monodisperse microspheres of a diameter 3–10 μm were synthesized by a method of heterophase copolymerization of ethylene glycol dimethacrylate or styrene with divinylbenzene and methacrylic acid on seed nuclei produced by dispersion polymerization of styrene. The diameter and distribution of the microspheres by size, their morphology and surface structure were analyzed by SEM. Factors that control these characteristics of the microspheres in the polymerization process were determined. Swelling ability of the microspheres in toluene and dimethylformamide was evaluated using optical microscopy. 相似文献
We prepared monodisperse polystyrene microspheres by dispersion polymerization using sodium polyaspartate (PAspNa) as a dispersion
stabilizer in an ethanol/water medium. The influence of reaction parameters, i.e., the volume fraction of ethanol in the medium,
stabilizer concentration, and the monomer concentration, on the average diameter of the prepared polystyrene microspheres
and its distribution were investigated. Polystyrene microspheres were successfully prepared, and the average diameter of the
prepared monodisperse polystyrene microspheres was controlled by adjusting the reaction parameters. The zeta potential of
the microspheres and the time course of conversion, the particle diameter and its distribution, and particle numbers were
also examined. It was found that PAspNa as a dispersion stabilizer provides an environmentally benign process for the preparation
of monodisperse polymer microspheres by dispersion polymerization. 相似文献
PDMAAm microspheres have been obtained by inverse suspension, inverse emulsion, and dispersion polymerization. Conventional inverse suspension polymerization in toluene/trichloroethene is modified by the use of ultrasound. The resulting hydrogel microspheres are examined by dynamic light scattering and scanning electron microscopy to afford the morphology, dispersity, and size of the microspheres. Inverse suspension polymerization yields 100‐µm particles, while those obtained by inverse emulsion polymerization are 0.13–1 µm in diameter. While the inverse techniques produce particles of broad size distribution, monodisperse microspheres are obtained by the Kraton G 1650‐stabilized dispersion polymerization of DMAAm in a toluene/heptane medium. The particle size and polydispersity could be controlled by the addition of water into the dispersed phase, and by varying the cellulose acetate butyrate or Kraton G 1650 concentration and the toluene/trichloroethene or toluene/heptane ratio.