Thermoresponsive gelling behavior of concentrated alumina suspensions containing poly(acrylic acid) and PEO-PPO-PEO copolymer

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• 作者：Akira Kondo^a ; ^{a-kondo@jwri.osaka-u.ac.jp} ; Hui Xu^b ; Hiroya Abe^a ; Makio Naito^a
• 关键词：Ceramics ; Solid free forming ; Physical gel ; PEO&ndash ; PPO&ndash ; PEO copolymer ; Poly(acrylic acid)
• 刊名：Journal of Colloid and Interface Science
• 出版年：2012
• 期刊代码：125_00219797
• 类别：ch
• 出版时间：1 May, 2012
• 卷：373
• 期：1
• 页码：20-26
• 文件大小：767 K

摘要

Thermoresponsive gelling behavior of concentrated alumina suspensions with poly(acrylic acid) (PAA) and triblock copolymer (PEO₁₀₁-PPO₅₆-PEO₁₀₁, Pluronic F127) was investigated as a function of PAA concentration (0.4-1.2 mass%) for ceramic solid free forming. The copolymer species assemble into micelles at temperatures above 15 掳C, yielding aqueous physical gel . In this study, the concentrated alumina aqueous suspensions (蠁 = 35 vol%) were first prepared using the anionic dispersant of PAA, and then the copolymer species (10 mass%) were dissolved at a cooled temperature at 10 掳C. The addition of the copolymer species had a negligible influence on the adsorption state of PAA onto the alumina surfaces. The PAA concentration needed for the saturation adsorption on the alumina surfaces was 鈭?.6 mass%. When the PAA concentration was this value or slightly less, the suspension became gel state at 30 掳C from low viscous state at 10 掳C. The thermally induced alumina gel had excellent viscoelastic properties, and thereby the three dimensional periodic ceramic structures were successfully fabricated by a direct colloidal printing method that using the gels as 鈥渟olid鈥?inks at the room temperature. On the other hand, when it exceeded the saturation adsorption limit, the gelling behavior was not observed, indicating that the non-adsorbing PAA species may partly suppress the micellization of the copolymer on the heating.