RT Journal Article
T1 Multiscale Quantitative Rheological Analysis of Composition−Temperature Relationships in Borate-Guar Hydrogels
A1 Martín Alfonso, María José
A1 Martínez Boza, Francisco José
A1 Luckham, Paul F.
AB Borate-cross-linked guar gum gels exhibit complex viscoelasticity driven by reversible covalent interactions between borate ions and cis-diol groups. Despite their widespread industrial use, limited knowledge of their thermorheological behavior makes it difficult to predict their performance at high temperatures. Here, 0.50 wt % guar gum dispersions with borax-to-guar ratios ranging from 1:1 to 1:8 (i.e., 0.5000−0.0625 wt % borax) were characterized from 25 to 140 °C using oscillatory rheometry. At 25 °C, gels displayed predominantly elastic behavior (G′ ≫ G″); above 120 °C, viscous behavior dominated due to thermally induced cross-link dissociation. Time−temperature superposition was valid up to 120 °C, and Arrhenius analysis yielded activation energies of 72−85 kJ mol−1 for junction relaxation and −10 to −21 kJ mol−1 for modulus decay. A borax threshold near 0.1250 wt % delineated weak from strong gel regimes. Steady shear measurements revealed a three-region flow curve, including shear-thickening and shear-thinning regions that depended on temperature and cross-link density. All formulations deviated from the Cox−Merz rule at high shear. These findings support predictive design of thermoresilient borate-guar gels for energy and high-temperature applications.
PB American Chemical Society
SN 2637-6105 (electrónico)
YR 2025
FD 2025
LK https://hdl.handle.net/10272/27646
UL https://hdl.handle.net/10272/27646
LA eng
NO Martín-Alfonso, M. J., Martínez-Boza, F. J., & Luckham, P. F. (2025). Multiscale Quantitative Rheological Analysis of Composition−Temperature Relationships in Borate-Guar Hydrogels. ACS Applied Polymer Materials, 7(23), 15896–15905. https://doi.org/10.1021/acsapm.5c02807
NO This work is part of the projects PID2023-151306OB-I00 and PID2023-149701OA-I00 funded by MICIU/AEI/10.13039/501100011033 (Spanish Ministry of Science and Innovation) and by the European Regional Development Fund (ERDF) of the European Union (“A way of making Europe”). Funding for open access charge: Universidad de Huelva/CBUA.
DS Repositorio Institucional de la Universidad de Huelva
RD 1 jun 2026