Investigation of Porous Structure of Aerogel Prepared from Nanofibrillated Cellulose

Abstract

Cellulose aerogels were prepared through changing the concentration of TEMPO-oxidized cellulose suspension and applying high-pressure homogenization, followed by regular or rapid freeze drying methods. The prepared cellulose aerogel was studied by scanning electron microscopy, BET analysis (nitrogen gas adsorption), and mercury intrusion porosimetry to investigate the effect of variables on the porous properties. In the present study, the porous structure of cellulose aerogel was well obtained by varying concentration of NFC and applying rapid freeze drying approach. The specific surface area of prepared cellulose aerogels varied linearly with adjusting concentrations of NFC, and the highest surface area of cellulose aerogel was attained at 2.0% concentration of NFC in this study. Compared to regular freezing in the freezer, rapid freezing in the liquid nitrogen prepared cellulose aerogel has a lower BET value but more uniform structure with relatively narrow pore size distribution.