A Systematic Study on Bio-Based Hybrid Aerogels Made of Tannin and Silica

Materials

Nicola Huesing¹  Ann-Kathrin Koopmann¹  Thomas Sepperer²  Wim J. Malfait³ 

[1] Department of Chemistry and Physics of Materials, Paris-Lodron University of Salzburg, 5020 Salzburg, Austria;Salzburg Center for Smart Materials, 5020 Salzburg, Austria;Swiss Federal Laboratories for Materials Science and Technology, Empa, 8600 Dübendorf, Switzerland;

关键词: porous materials;    aerogels;    tannin;    silica;   

DOI  :  10.3390/ma14185231

来源: DOAJ

【 摘 要 】

Tannin-silica hybrid materials are expected to feature excellent mechanic-chemical stability, large surface areas, high porosity and possess, after carbothermal reduction, high thermal stability as well as high thermal conductivity. Typically, a commercially available tetraethoxysilane is used, but in this study, a more sustainable route was developed by using a glycol-based silica precursor, tetrakis(2-hydroxyethyl)orthosilicate (EGMS), which is highly water-soluble. In order to produce highly porous, homogeneous hybrid tannin-silica aerogels in a one-pot approach, a suitable crosslinker has to be used. It was found that an aldehyde-functionalized silane (triethoxysilylbutyraldehyde) enables the covalent bonding of tannin and silica. Solely by altering the processing parameters, distinctly different tannin-silica hybrid material properties could be achieved. In particular, the amount of crosslinker is a significant factor with respect to altering the materials’ properties, e.g., the specific surface area. Notably, 5 wt% of crosslinker presents an optimal percentage to obtain a sustainable tannin-silica hybrid system with high specific surface areas of roughly 800–900 m² g⁻¹ as well as a high mesopore volume. The synthesized tannin-silica hybrid aerogels permit the usage as green precursor for silicon carbide materials.

【 授权许可】

Unknown