Polyimide-Surface-Modified Silica Tubes: Preparation and Cryogenic Properties

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• 作者：Yihe Zhang ; Yuanqing Li ; Guangtao Li ; Haitao Huang ; H. L. W. Chan ; Walid A. Daoud ; John H. Xin ; Laifeng Li
• 刊名：Chemistry of Materials
• 出版年：2007
• 出版时间：April 17, 2007
• 年：2007
• 卷：19
• 期：8
• 页码：1939 - 1945
• 全文大小：537K
• 年卷期：v.19,no.8(April 17, 2007)
• ISSN：1520-5002

文摘

The silica tubes were synthesized by template self-assembly from D,L-tartaric acid and hydrolysis oftetraethoxysilane (TEOS), and their surfaces were modified by a 3-aminopropyltriethoxysilane couplingagent. Thereafter, a series of polyimide (PI)-surface modified silica tube (ST) hybrid films was preparedfrom PMDA-ODA in N,N-dimethylacetamide as a solvent using an in situ polymerization process combinedwith ultrasonic dispersion and multistep curing. The resulting silica tubes and the hybrid films werecharacterized using XRD, SEM, TEM, FTIR, and UV-vis. The cryogenic mechanical properties at 77K and dynamic mechanical properties of the hybrid films were studied. The results indicated that thestrength, modulus, and failure strain of the hybrid films were all increased compared with those of thepure PI film when the silica tube content was at 1-3 wt %. The cryogenic tensile strength and moduluswere generally higher than those at room temperature, whereas the cryogenic failure strain was lowerthan that at room temperature. The elastic modulus of the hybrid films exhibited a monotonically increasingtrend. The cryogenic failure strain of hybrid films with 1-3 wt % silica tube contents was greater thanwith 15 wt %, indicating a good ductility at 77 K. The glass-transition temperature of the hybrid filmsincreased with the increase in silica tube content.