Structure-Property Relationships in Porous 3D Nanostructures as a Function of Preparation Conditions: Isocyanate Cross-Linked Silica Aerogels

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• 作者：Mary Ann B. Meador ; Lynn A. Capadona ; Linda McCorkle ; Demetrios S. Papadopoulos ; Nicholas Leventis
• 刊名：Chemistry of Materials
• 出版年：2007
• 出版时间：May 1, 2007
• 年：2007
• 卷：19
• 期：9
• 页码：2247 - 2260
• 全文大小：1684K
• 年卷期：v.19,no.9(May 1, 2007)
• ISSN：1520-5002

文摘

Sol-gel-derived silica aerogels are attractive candidates for many unique thermal, optical, catalytic,and chemical applications because of their low density and high mesoporosity. However, their inherentfragility has restricted use of aerogel monoliths to applications in which they are not subject to any load.We have previously reported cross-linking of the mesoporous silica structure of aerogels withdi-isocyanates, styrenes, or epoxies reacting with amine-decorated silica surfaces. These approaches havebeen shown to significantly increase the strength of aerogels with only a small effect on density or porosity.Though density is a prime predictor of properties such as strength and thermal conductivity for aerogels,it is becoming clear from previous studies that varying the silica backbone and size of the polymercross-link independently can give rise to combinations of properties that cannot be predicted from densityalone. Herein, we examine the effects of four processing parameters for producing this type of polymercross-linked aerogel on properties of the resulting monoliths. We focus on the results of ¹³C CP-MASNMR, which gives insight to the size and structure of polymer cross-link present in the monoliths andrelates the size of the cross-links to microstructure, mechanical properties, and other characteristics ofthe materials obtained.