Cellulose, the most abundant renewable resource on earth, has characteristics of safety, hydrophilicity, biocompatibility and biodegradability. Gathering the advantages of cellulose as well as high mechanical strength feature of organic aerogels, cellulose aerogels, generally prepared by gelation of cellulose solution followed by drying with supercritical CO2, have been attracting more and more attention. Generally, a non-solvent such as ethanol is used as a gelation bath in which cellulose solution held in a small vessel is immersed to induce a gelation process. The problems caused by volatile ethanol as the non-solvent are concerned with the safety, environmental aspect and high cost.  In this work, inorganic salts were added into the cellulose solution to induce the gelation to get the gel for cellulose aerogel. With 4wt% cellulose dissolved in 7wt% NaOH/12wt% urea aqueous solution, which was kept hermetically at room temperature, the gelation took place in 2 hours when a small quantity of inorganic salts in the solution, while the cellulose solution without the additive salt kept liquid status for more than two weeks. At elevated temperatures, the gelation of the cellulose solution can be achieved simply by staying hermetically in several hours, which we call as a thermally induced gelation, while the addition of inorganic salts remarkably accelerated the gelation process. At a certain temperature, both category and amount of the additive salt affected significantly on the gelation speed. Based on the salt-induced gelation, cellulose aerogels were prepared in a more efficient way. According to the SEM and N2adsorption measurements, there was no obvious structure difference between the cellulose aerogels made through the salt�induced gelation, the thermally induced gelation and the non-solvent gelation.

Salt-induced gelation for cellulose aerogel preparation

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.