Preparation Of Carbon-based Spheres Using Aromatic Ring-bridged Polybissilsesquioxanes

As a family of the organic-inorganic hybrid silicas, polybissilsesquioxanes are formed by introducing organic groups into the silica framework through two covalent bonds. They possess considerable mechanical strength from the inorganic silica and flexibility from the organic moiety, respectively. Meanwhile, the organic groups provide new active reaction center to the materials. Therefore, they have wide applications in catalyst supports, drug delivery, adsorption and separation. In this thesis, varieties of carbon-based spheres were fabricated from core-shell structured silica@polybissilsesquioxane composite spheres. The main work was shown as following:Firstly, silica spheres were prepared through a classic st?ber method. They were used as hard templates, and 4,4’-bis(triethoxysilyl)-1,1’-biphenyl was used as organic precursor.Core-shell structured silica@polybissilsesquioxane composite spheres were obtained by covering a layer of 4,4’-biphenylene-bridged polybissilsesquioxane on the surface of the silica spheres.Secondly, after the core-shell structured silica@polybissilsesquioxane spheres were treated by carbonizing under different temperature, magnesiothermic reducing and etching,respectively, three kinds of samples were obtained, including:(1) hollow carbonaceous hemispheres(or spheres) with high specific surface area,(2) hollow silicon carbide/carbon spheres and hollow crystallized silicon carbide spheres,(3) core-shell structured silicon@silicon carbide/carbon composites which showed good cycling performance in lithium ion batteries.Finally, micron-sized silica@4,4’-biphenylene-silica spheres were also prepared by covering 4,4’-biphenylene-bridged polybissilsesquioxane on the surface of commercial silica spheres. This material could be used as stationary phase for HPLC column, and exhibit high separation ability for benzene and its derivatives.