Preparation of bulk sodium carboxymethyl cellulose aerogels with tunable morphology

• Bulk carboxymethyl cellulose aerogels with low density and high porosity were obtained by a novel and facile process.
• By adjusting the mass fraction of Fe3+, granular, three-dimensional network and rod-like morphology were obtained, in reflection of different coordination numbers, responding to the profile of SEM.
• With the addition of Fe3+, the crystal degree and thermal stability were decreased, because of both the coordination between iron ion and carboxylate ion and iron ions penetrated into crystal lattice.

Homogeneous and bulk carboxymethyl cellulose hydrogel and aerogel were prepared by a novel process, using Fe3+ and d-(+)-gluconic acid-lactone as cross-linker and releasing agent, respectively. The results showed that the mass fraction of Fe3+ has a great effect on CMC aerogels’ structure, crystallization and morphology. By adjusting the mass fraction of Fe3+, granular, three-dimensional network and rod-like morphology were obtained, responding to varying density and porosity. The aerogel had low density (low to 0.0568 g/cm3) and high porosity (up to 90.45%). Meantime. Combination patterns between carboxylate ion and iron ion were checked by FTIR. Furthermore, with the addition of Fe3+, lattice mismatch of CMC emerged and led to decreasing crystalline degree and thermal stability. This work would play an important role in the handy and extensive application of CMC aerogels