Synthesis of Nanoscale Shell-core Titania Coated Silica Particles in the Presence of Polyether Polyamine and the Phase Transition  

作　　者：HUA Feng-jun SUN Jun HONG Ke GAO Lian YANG Yu-liang 

机构地区：[1]Key Laboratory of Molecular Engineering of Polymer,Fudan University,Shanghai 200433,P.R.China [2]State Key Laboratory of High Performance Ceramics and SuperfineMicrostructure,Shanghai Institute of Ceramics,Shanghai 200433.P.R.China

出　　处：《Chemical Research in Chinese Universities》2002年第1期70-74,共5页高等学校化学研究(英文版)

基　　金：Supported by the State Key L aboratory of Shanghai Institute of Ceram ics and State Key L aboratory of Surface Physicsin China

摘　　要：The nanoscale titania coated silica was prepared via a two-step precipitating approach, where the nanoscale silica nuclei were first prepared by passing an aqueous solution of sodium silicate through an ion-exchange resin bed, then coated with the precipitation from hydrolyzed butyl titanate in an ethanol-hexane mixture at a low pH value in the presence of poly(ethylene oxide) polyamine salt(PPA) at a high temperature of 90 ℃. In the second-step precipitating process, the spontaneously precipitated titania shell on the silica nuclei was stabilized in the suspension solution with the help of the adsorption of PPA on the particles. A possible precipitating mechanism was suggested. Furthermore, the amorphous titania shell could undergo crystallization from the amorphous to the anatase structure at a high temperature of 650 ℃, and a further phase transition from the anatase to the rutile structure in the different sintering processes at a rising temperature of 750 ℃.The nanoscale titania coated silica was prepared via a two-step precipitating approach, where the nanoscale silica nuclei were first prepared by passing an aqueous solution of sodium silicate through an ion-exchange resin bed, then coated with the precipitation from hydrolyzed butyl titanate in an ethanol-hexane mixture at a low pH value in the presence of poly(ethylene oxide) polyamine salt(PPA) at a high temperature of 90 ℃. In the second-step precipitating process, the spontaneously precipitated titania shell on the silica nuclei was stabilized in the suspension solution with the help of the adsorption of PPA on the particles. A possible precipitating mechanism was suggested. Furthermore, the amorphous titania shell could undergo crystallization from the amorphous to the anatase structure at a high temperature of 650 ℃, and a further phase transition from the anatase to the rutile structure in the different sintering processes at a rising temperature of 750 ℃.

关 键 词：Nanoscale particle Silica sol Titania coated silica 

分 类 号：O631[理学—高分子化学]