Monovalent salt and pH-induced gelation of oxidized cellulose nanofibrils and starch networks: Combining rheology and small-angle X-Ray scattering

Hossain, Kazi M. Zakir, Calabrese, Vincenzo, Da Silva, Marcelo A., Bryant, Saffron J., Schmitt, Julien, Ahn-Jarvis, Jennifer H., Warren, Frederick J., Khimyak, Yaroslav Z., Scott, Janet L. and Edler, Karen J. (2021) Monovalent salt and pH-induced gelation of oxidized cellulose nanofibrils and starch networks: Combining rheology and small-angle X-Ray scattering. Polymers, 13 (6). ISSN 2073-4360

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Abstract

Water quality parameters such as salt content and various pH environments can alter the stability of gels as well as their rheological properties. Here, we investigated the effect of various concentrations of NaCl and different pH environments on the rheological properties of TEMPO-oxidised cellulose nanofibril (OCNF) and starch-based hydrogels. Addition of NaCl caused an increased stiffness of the OCNF:starch (1:1 wt%) blend gels, where salt played an important role in reducing the repulsive OCNF fibrillar interactions. The rheological properties of these hydrogels were unchanged at pH 5.0 to 9.0. However, at lower pH (4.0), the stiffness and viscosity of the OCNF and OCNF:starch gels appeared to increase due to proton-induced fibrillar interactions. In contrast, at higher pH (11.5), syneresis was observed due to the formation of denser and aggregated gel networks. Interactions as well as aggregation behaviour of these hydrogels were explored via ζ-potential measurements. Furthermore, the nanostructure of the OCNF gels was probed using small-angle X-ray scattering (SAXS), where the SAXS patterns showed an increase of slope in the low-q region with increasing salt concentration arising from aggregation due to the screening of the surface charge of the fibrils.

Item Type: Article
Uncontrolled Keywords: cellulose nanofibrils,rheology,saxs,salt,starch,ph,chemistry(all),polymers and plastics ,/dk/atira/pure/subjectarea/asjc/1600
Faculty \ School: Faculty of Science > School of Pharmacy
Related URLs:
Depositing User: LivePure Connector
Date Deposited: 09 Apr 2021 23:49
Last Modified: 13 May 2021 16:21
URI: https://ueaeprints.uea.ac.uk/id/eprint/79659
DOI: 10.3390/polym13060951

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