Synergistic effect of glycerol and ionic strength on the rheological behavior of cellulose nanocrystals suspension system

To broaden the application of cellulose nanocrystals (CNCs) in the field of biopolymer nanocomposites, a systematic assessment of the viscoelastic properties of CNC suspensions in the presence of glycerol (Gly) and/or sodium chloride (NaCl) was conducted. The viscosity, storage modulus (G'), and loss modulus (G '') increased with increasing concentrations of CNCs and Gly, respectively. Dramatically, the G' and G '' values were raised and tan delta (<1) decreased with the increasing addition of NaCl, indicating that the elastic properties of CNCs in NaCl solutions continuously strengthened, thereby the gel-like response of the network was enhanced. Moreover, the addition of 40% Gly significantly increased the values of G' and G '' for CNCs in NaCl solutions. This work demonstrates new findings related to the rheological properties of CNC gels with Gly/NaCl, and accounts for the interaction mechanisms between CNCs and CNCs/Gly/NaCl, with electrostatic interactions, hydrogen bonds, van der Waals forces, and Na+ bridging. We wish our study could better serve for future works based on design of CNCs in biomedical and packaging materials industries. (C) 2017 Elsevier B.V. All rights reserved.