Study On Fabrication And Properties Of Composites Coated On The Modified Polystyrene Spheres

A novel approach to fabricate polystyrene/silver/polypyrrole (PS/Ag/PPY) nanocomposites is developed in this paper. The PS microspheres with the average size of 740 nm are prepared by dispersed polymerization and sulfonated in order to be used as templates for the synthesis of PS/Ag/PPY nanocomposites. Then, [Ag(NH3)2]+ ions are adsorbed onto the surface of sulfonated PS core-shell gel spheres via electrostatic attraction. Subsequently, [Ag(NHs)2]+ions are reduced by pyrrole monomers and oxidative polymerization of pyrrole is simultaneously carried out to obtain PS/Ag/PPY nanocomposites. The final products exhibit excellent catalytic properties both in efficiency and recyclability for the reduction of organic dyes, indicating that the nanocomposites will have promising applications in catalysis. Monodisperse PS microspheres applied as templates were immersed in concentrated sulfuric acid in order to graft-SO3H groups on the surface of the particles. Afterward, these core-shell spheres were dispersed in ethanol and then a freshly prepared aqueous solution of [Ag(NH3)2]+ was added into the above dispersion at room temperature to prepare PS/[Ag(NH3)2]+ spheres, which were washed twice with deionized water. Finally, on the surface of the templates, [Ag(NH3)2]+ ions were reduced to Ag nanoparticles and pyrrole monomers were oxidized to polypyrrole simultaneously to form PS/Ag/PPY nanocomposites.A novel method to fabricate silica hollow spheres was presented in the paper. Silica particles were first coated onto the sulfonated polystyrene core-shell template spheres, and then the template spheres were’dissolved’ in ammoniacal ethanol solution to prepare silica hollow spheres directly. During the formation of silica hollow spheres, the additional calcination process was not needed in the method to remove the templates. Moreover, the dissolution conditions were very mild, rather than high temperature and long time. The PS particles prepared by dispersion polymerization were sulfonated first in concentrated sulfuric acid in order to be utilized as templates for the synthesis of silica nanoshells. With the ammonia-catalyzed hydrolysis and condensation of TEOS, the silica forms a shell on the surface of the sulfonated PS particles because of the well compatibility between-SO3H groups and -OH groups. However, the negative charged-SO3H and -OH can create a repulsive force to prevent the formation of SiO2/PS composite spheres. To solve the problem, the approach to control the degree of sulfonation is taken to reduce the repulsive force so that the compatibility of the polar groups plays a leading role in the synthesis of SiO2/PS composite particles. Ultimately, sulfonated PS spheres are ’dissolved’ in ammoniacal ethanol solution at 60℃ to obtain silica hollow spheres...