Production of biodegradable superabsorbent aerogels using a supercritical CO2 assisted drying

Superabsorbent polymers (SAPs) are organic materials possessing high capacity to absorb and retain large volumes of water, saline and physiological solutions (at least 10-20 times their weight). The most commonly used SAPS are acrylated-based polymers that are not biodegradable or recyclable. To overcome these limits, carboxymethylcellulose (CMC) with hydroxyethylcellulose (HEC) hydrogels were synthetized in this work and dried using a supercritical assisted process at 200 bar and 45 degrees C. The solvent exchange procedure influenced the final aerogel morphology and, thus, the aerogel swelling ratio (SR). A solvent exchange starting from 50 % v/v ethanol, preserved the native gel nanofibrous morphology, producing a SR up to 20 times larger than the ones reported in the literature using the same process, corresponding to a water uptake larger than 500 times the weight of the dried aerogel. (C) 2019 Elsevier B.V. All rights reserved.