Fabrication of highly porous starch monoliths and their application as green desiccants

Starch monoliths with oriented porous structures were developed from starches and glycerin as a plasticizer using unidirectional freeze-drying technology. The morphology of the porous starch monoliths made from different starches was determined by scanning electron microscopy (SEM), and the porosity, mechanical properties and moisture absorption of the porous materials were evaluated. The results show that porous starch monoliths made from oxidized starch with 15% glycerin had good mechanical strength with the best moisture absorption. Increasing the starch concentration significantly improved their strength and increased the moisture absorption rate as well. The moisture absorption of the porous monolith made from oxidized starch is comparable with commonly used desiccants. The porous starch monoliths can successfully remove water from 95% ethanol to produce absolute ethanol due to their selective absorption for water. Copyright © 2011 John Wiley & Sons, Ltd.