Preparation of Hydrophobic TiO2 Powders by Silane Coupling Agent Treatment Using Alkyltrimethoxysilane Agents
| Autor: | Hiroshi Majima, Masahide Miyano, Toshihiro Yoshinaga, Sumiko Sanuki |
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| Rok vydání: | 2002 |
| Předmět: | |
| Zdroj: | Journal of the Surface Finishing Society of Japan. 53:688-693 |
| ISSN: | 1884-3409 0915-1869 |
| DOI: | 10.4139/sfj.53.688 |
| Popis: | Oligomer formation reactions during the preliminary treatment of a solution system consisting of ATMS-EtOH-H2 O were investigated using alkyltrimethoxysilane (ATMS) agents. Also, the preparation of hydrophobic TiO2 powders with ATMS agents was examined. The main findings of this study were as follows: (1) The amount of monomer of ATMS decreased during hydrolysis and condensation polymerization and the consumption rate at the initial stage up to 20% slowed in accordance with a decrease in the carbon number of the alkyl group of ATMS. However, the consumption rate exhibited a minimum value at a carbon number of 4-6 when the reaction proceeded further. (2) The average molecular weight of the oligomer determined from GPC elution curve increased with the duration of preliminary treatment. Condensation polymerization rates increased in the order n-DTMS, i-BTMS, n-PTMS, n-BTMS, and n-HTMS. (3) M value, which is a parameter of hydrophobic degree, increased with the increase in carbon number of the alkyl group of n-ATMS, ranging from 75% to 55%, while that of i-BTMS was 45%. (4) M values of TiO2 powders treated with each optimal amount of n-PTMS, n-BTMS, and i-BTMS increased with the duration of preliminary treatment, however, the time required to reach maximum M values took longer in the order i-BTMS, n-BTMS, and n-PTMS. By contrast, maximum M values were obtained with n-HTMS and n-DTMS without preliminary treatment of ATMS-EtOH-H2O solution, providing a hydrophobic property to TiO2 powders by mixing TiO2 and solution containing silane coupling agent, followed by heat treatment. (5) Average polymerization degrees promised maximum M values for TiO2 using n-PTMS, n-BTMS, n-HTMS, i-BTMS, and n-DTMS were 3.0, 2.1, 1.7, 1.4 and 1.0, respectively. |
| Databáze: | OpenAIRE |
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