Rheological properties of hydrogels produced by cellulose derivatives cross-linked with citric acid, succinic acid, and sebacic acid

Authors: Xu, Jingyuan - James; BODDU, VEERA - ENVIRONMENTAL PROTECTION AGENCY (EPA); Liu, Sean

Submitted to: Cellulose Chemistry and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2022
Publication Date: 2/23/2022
Citation: Xu, J., Boddu, V.M., Liu, S.X. 2022. Rheological properties of hydrogels produced by cellulose derivatives cross-linked with citric acid, succinic acid, and sebacic acid. Cellulose Chemistry and Technology. 56 (1-2), 49-54. https://doi.org/10.35812/CelluloseChemTechnol.2022.56.04.
DOI: https://doi.org/10.35812/CelluloseChemTechnol.2022.56.04

Interpretive Summary: Cellulose is the most plentiful biopolymer on earth and a natural, biodegradable and inexpensive resource for biomaterials such as hydrogels. Hydrogels have many applications such as water absorption coating materials for agricultural seeds, drug delivery systems, wound-healing substances, and cosmetic gels. ARS researchers at Peoria, Illinois, developed cellulose-based hydrogels by reacting the cellulose derivatives with three organic acids (citric acid, succinic acid, and sebacic acid), which served as cross-linkers. In order to identify potential applications of these cellulose-based hydrogels, the flow behaviors (rheological properties) were investigated. We explored the effects of concentration on the rheological properties of the cellulose-based hydrogels. We found that the flow behaviors of these biodegradable hydrogels can be manipulated with different cross-linkers and hydrogel concentrations. Therefore, by applying such adjustments, we can prepare various inexpensive biodegradable cellulose-based hydrogels and tailor them according to different uses, for example as hair gels or wound-healing materials.

Technical Abstract: Cellulose is the most plentiful biopolymer in our world, and a natural, biodegradable and inexpensive resource for biomaterials. This work prepared cellulose-based hydrogels by cross-linking cellulose derivatives using citric acid, succinic acid, and sebacic acid and explored the rheological properties of the three cellulose-based hydrogels. We found that the viscoelastic properties of cellulose-based biodegradable hydrogels can be manipulated by hydrogel concentration and using different cross-linkers. The cellulose-based hydrogels cross-linked with citric acid (CHCCA) or succinic acid (CHCSUA) exhibited nearly identical rheological behaviors (both linear and non-linear) due to the similar structure of the citric acid and succinic acid. Both CHCCA and CHCSUA showed similar viscoelastic solid gel-like behaviors, and the viscoelastic properties were stronger when hydrogel concentrations were greater. The CHCCA and CHCSUA also displayed nearly identical shear thinning behaviors among all measured shearing rates. The cellulose-based hydrogels cross-linked with sebacic acid (CHCSEA) exhibited viscoelastic liquid or fluid-like behaviors, which are clearly different from those for the CHCCA and CHCSUA. The CHCSEA showed shear thinning characteristic during high shearing rates but a Newtonian region at low shearing rates. This work paves the way for developing various inexpensive biodegradable cellulose-based hydrogels with desired rheological properties specific to applications such as cosmetic gels and wound-healing materials.