Preparation of functional macroporous ZrO2/Ti nanocomposites by Pickering Emulsion
| Autor: | Kai-Ting Hsu, 許凱婷 |
|---|---|
| Rok vydání: | 2014 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 102 This study prepares macroporous ZrO2/Ti composite foams from using surfactant-modified hydrophobic ZrO2 and hydrophilic Ti particles in water via the Pickering emulsion route. Surface potential is positive for the ZrO2 particles in water. This facilitates preferential adsorption of anionic AOT molecules on the ZrO2 particle surface so that the initially hydrophilic ZrO2 becomes hydrophobic with contact angle changing from 20o to 105o. When solids concentration of the ZrO2 suspension is varied, we observe that the ZrO2 particles reside stably at the air-water interface when the solids content was 5vol%. Further adjusting the AOT concentration to 0.5 cmc, we’ve found holes existing at the air-water interface; to which, porosity is about 89~92% by mercury intrusion porosimetry and three-point bending test reveals the bending strength of the foams in a range of 30~45 kPa. Gelcasting is used to quick set the composite foam by adding agar. The setting time is shorten to 5 minute when the agar concentration is 1.0wt% with the AOT modified ZrO2 stably reside at the air-water interface during the emulsion process. Adding different ratios of the Ti particles in the ZrO2 colloid, we’ve found that the macroporous composite microstructure varies when adjusting the ZrO2 fractions in the colloid, resulted in distribution of the ZrO2 and Ti in the cell wall. The porosity is characterized by the mercury intrusion porosimetry to be at 77~81%, and the three point bending test reveals the bending strength in a range of 370~630 kPa. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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