Production of biodegradable superabsorbent aerogels using asupercritical CO2 assisted drying

tSuperabsorbent polymers (SAPs) are organic materials possessing high capacity to absorb and retainlarge volumes of water, saline and physiological solutions (at least 10-20 times their weight). Themost commonly used SAPs are acrylated-based polymers that are not biodegradable or recyclable. Toovercome these limits, carboxymethylcellulose (CMC) with hydroxyethylcellulose (HEC) hydrogels weresynthetized in this work and dried using a supercritical assisted process at 200 bar and 45oC. The solventexchange 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.