Microencapsulation of TiO₂ Nanoparticles with Polymer by Rapid Expansion of Supercritical Solution

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• 作者：Kiyoshi Matsuyama ; Kenji Mishima ; Ken-ichiro Hayashi and Hideto Matsuyama
• 关键词：supercritical carbon dioxide ; RESS ; nanoparticles ; microencapsulation ; cosolvent
• 刊名：Journal of Nanoparticle Research
• 出版年：2003
• 出版时间：2003
• 年：2003
• 卷：5
• 期：1/2
• 页码：87-95
• 全文大小：273 KB

文摘

A novel preparation method is reported for the microencapsulation of TiO₂ nanoparticles by rapid expansion of supercritical solution with a nonsolvent. A suspension of TiO₂ nanoparticles in carbon dioxide containing a cosolvent and dissolved polymer is sprayed through a nozzle to atmospheric pressure. After rapid expansion, polymer microspheres were obtained. The microspheres do not tend to agglomerate, since the pure cosolvent is a nonsolvent for the polymer. The structure and morphology of microspheres were investigated by SEM, TEM and XRD. The obtained polymer microspheres are microcapsules of TiO₂ nanoparticles. The mean particle diameter and particle size distribution of microcapsules, could be controlled by changing the polymer concentration, pre-expansion pressure, temperature and injection distance. The polymer feed compositions are more effective than other factors on the control of particle size.