Thermoplastic and thermosetting properties of polyphenylsilsesquioxane particles prepared by two-step acid-base catalyzed sol-gel process |
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| Authors: | Kenji Takahashi Kiyoharu Tadanaga Atsunori Matsuda Akitoshi Hayashi Masahiro Tatsumisago |
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| Institution: | (1) Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai Osaka, 599-8531, Japan;(2) Department of Materials Science, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi Aichi, 441-8580, Japan |
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| Abstract: | Polyphenylsilsesquioxane (PhSiO3/2) particles were synthesized by a two-step acid-base catalyzed sol-gel process, in which phenyltriethoxysilane used as a starting
alkoxide was hydrolyzed and condensed in the first step under two different acid-catalyzed conditions. The PhSiO3/2 particles prepared under an acid-catalyzed process without using a solvent were thermally hardened after the first heating
up to 200°C. In contrast, the PhSiO3/2 particles prepared under an acid-catalyzed process with ethanol as a solvent were thermally softened with the repeated heating
processes up to 200°C. From the gel permeation chromatography measurements, it was found that the average molecular weight
of the particles prepared with the use of ethanol was decreased in comparison with that of the particles prepared without
using ethanol. The addition of ethanol in the sols during hydrolysis and condensation reaction under the acid-catalyzed process
caused the decrease in the average molecular weight, which should result in the changes of thermal property of PhSiO3/2 particles from thermosetting to thermoplastic. |
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| Keywords: | Sol-gel method Polyphenylsilsesquioxane Glass transition Particles |
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