Liquid Desiccant Solvent Extraction of Alumina-Filled Thermoreversible Gels

摘要

A liquid desiccant solvent extraction technique is introduced to significantly reduce the amount of warping during drying in thermoreversibly gelcast alumina samples by eliminating capillary stresses during the initial solvent removal stage. This process is combined with a secondary drying step in a vacuum oven with an in-line solvent trap, allowing for the complete recovery of the alcohol solvent used in producing gels. Optimal concentrations and immersion times for poly(tert-butyl acrylate)-based and water-based liquid desiccants are determined, along with the osmotic stresses and equilibrium solvent concentrations of gels immersed in these desiccants. Solvent loss during the liquid desiccant solvent extraction step, volumetric shrinkage during drying and sintering, and sintered porosity are measured. It is determined that a -10 wt% poly (fert-butyl acrylate)/90 wt% isopropyl alcohol liquid desiccant is optimal.