Synthesis and Properties of Flexible Silica Aerogels as a Precursor for Si-O-C Aerogels

Abstract

This bachelor thesis is about the production of flexible aerogels as a precursor for Si-O-C aerogels. Two organo-modified silica sources, MTMS and GPTMS, as well as a coupling agent were chosen for reaction. The first part deals with the synthesis and characterization of flexible MTMS/GPTMS aerogels. Well known compositions of MTMS, GPTMS and DETA become flexible by the use of certain amounts of water and methanol. The procedure of preparing the gels as well as washing and drying is described. Two series of samples were produced. One had a higher content of water and the other had a higher content of methanol. After supercritical drying the aerogels obtained were characterized. Specific surface area, density, Young's modulus and microstructure are a few of the properties measured. The second part deals with the pyrolysis and the characterization of the pyrolyzed samples. Again specific surface area, density, Young's modulus, microstructure and other properties were measured. FTIR spectra were taken trying to determine the chemical bonds of the pyrolyzed aerogels.