Monolithic composites of silica aerogel with poly(methyl vinyl ether) and the effect of polymer on supercritical drying

Abstract

Novel monolithic and crack-free poly(methyl vinyl ether) (PMVE)-silica aerogel composites were synthesized using a modified sol gel procedure. The presence of PMVE in solid network of the composite samples was confirmed by a variety of techniques including IR spectroscopy, TGA and BET. Extraction of ethanol from alcogel composite rods using scCO(2) was investigated both by experiments and simulations. Partial differential equations representing mass transfer within the composite alcogel phase and in the flowing scCO(2) phase were developed and solved using finite difference method. Mass of ethanol removed from the samples as a function of time were found to be in good agreement with model results using mass transfer coefficients regressed from the experimental data. Effect of the polymer content on the drying could be estimated by taking into account of porosity change with polymer incorporation. Drying time of the alcogel increased with increasing weight fraction of polymer in the silica network and gel thickness.