Cellulose–silica aerogels

• Published in: Carbohydrate polymers 2015-05, Vol.122, p.293-300
• Main Authors: Demilecamps, Arnaud, Beauger, Christian, Hildenbrand, Claudia, Rigacci, Arnaud, Budtova, Tatiana
• Format: Article
• Language: English
• Subjects: Adsorption; Aerogels; Cellulose; Cellulose - chemistry; Engineering Sciences; Gels; Hydrophobic and Hydrophilic Interactions; Nanostructured composites; Nitrogen - metabolism; Silica; Silicon Dioxide - chemistry; Specific surface area; Thermal Conductivity
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2015.01.022

•Improved method of making cellulose–silica aerogels is proposed.•Formation of interpenetrated organic–inorganic network of aerogels is confirmed.•Composite aerogel has very high specific surface area due to mesoporous silica.•Composite aerogels are stiffer than each of reference aerogel.•Thermal conductivity of composite aerogel is lower than that of cellulose aerogel. Aerogels based on interpenetrated cellulose–silica networks were prepared and characterised. Wet coagulated cellulose was impregnated with silica phase, polyethoxydisiloxane, using two methods: (i) molecular diffusion and (ii) forced flow induced by pressure difference. The latter allowed an enormous decrease in the impregnation times, by almost three orders of magnitude, for a sample with the same geometry. In both cases, nanostructured silica gel was in situ formed inside cellulose matrix. Nitrogen adsorption analysis revealed an almost threefold increase in pores specific surface area, from cellulose aerogel alone to organic-inorganic composite. Morphology, thermal conductivity and mechanical properties under uniaxial compression were investigated. Thermal conductivity of composite aerogels was lower than that of cellulose aerogel due to the formation of superinsulating mesoporous silica inside cellulose pores. Furthermore, composite aerogels were stiffer than each of reference aerogels.