Convective drying of gels: comparison between simulated and experimental moisture profiles obtained by X-ray microtomography

in Thorat, B. N. (Ed.) Drying 2008 - Proceedings of the 16th International Drying Symposium (IDS2008), Vol. C. (2008, November)

Evolution of mechanical properties and final textural properties of resorcinol-formaldehyde xerogels during ambient air drying

in Journal of Non-Crystalline Solids (2008), 354(10-11), 831-838

Porous carbon xerogels can be obtained by convective drying of resorcinol (R)-formaldehyde (F) hydrogels, followed by pyrolysis. Drying conditions have to be carefully controlled when crack-free monoliths ... [more ▼]

Porous carbon xerogels can be obtained by convective drying of resorcinol (R)-formaldehyde (F) hydrogels, followed by pyrolysis. Drying conditions have to be carefully controlled when crack-free monoliths with well-defined shape and size are required. The knowledge of the mechanical properties of the RF xerogels and their evolution with water content is essential to model their thermo-hygro-mechanical behavior during convective drying and avoid mechanical stresses leading to deformation and cracking of the sample. The shrinkage behavior and the mechanical properties of RF xerogels obtained with R/C ratio ranging from 300 to 1500 were investigated. R/C greatly influences the shrinkage and mechanical properties of the wet gel, on the one hand, and the mechanical and textural properties of the dried gel, on the other hand. The smaller the R/C, the higher the shrinkage, the stiffening, and the viscoelastic character of the xerogels. Water content has an influence on both the stiffness of the gels and the viscoelastic response. Generally, samples lose their mechanical viscous character and become more rigid when they are dried. Finally., mercury porosimetry measurements showed that the gels exhibit a marked lowering of their stiffness upon compression, interpreted as a result of the heterogeneity of the microstructure. (C) 2007 Elsevier B.V. All rights reserved. [less ▲]

Effect of sample size on the mechanical stresses induced during the convective drying of highly shrinking materials

in Proceedings of the joint conference of AFSIA and Drying Working group of EFCE at Casino Municipal Biarritz, France, 24th and 25th May, 2007 (2007, May)

Thermo-hygro-mechanical modelling of the convective drying of resorcinol-formaldehyde xerogel monoliths

in Proceedings of Carbon 2006 (2006, July)

Textural comparison of resorcinol-formaldehyde xerogels obtained by vacuum drying and convective drying

Poster (2005, July)

Production of resorcinol formaldehyde xerogels by convective drying

in Proceedings of the joint conference of AFSIA (Association Française pour le Séchage dans l’Industrie et l’Agriculture) and Working group on Drying of EFCE at INA P-G, Paris, 12th and 13th May, 2005 (2005, May)