a1 Department of Chemistry, Jilin University, Changchun, People's Republic of China, 130023
a2 Department of Chemistry, Drexel University, Philadelphia, Pennsylvania 19104
A bulk sol-gel process has been developed to prepare monolithic silica materials at room temperature. The process involves an acid-catalyzed hydrolysis of tetraethyl orthosilicate in tetrahydrofuran containing aqueous HC1 catalyst, followed by neutralization with carbonate salts, extraction with aliphatic nonpolar solvents, molding, gelation, and drying. This method shortens the processing time from weeks for the conventional sol-gel process to several days. The silica objects prepared from the process are transparent, crack-free, and of relatively low volume shrinkage (e.g., 52%) and high silica content (e.g., 82%).
(Received May 27 1999)
(Accepted July 12 1999)
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