Absorption Properties of pH-Responsive Carboxymethyl Cellulose Hydrogels Crosslinked with Epichlorohydrin and Citric Acid; [ 에피클로로히드린과 시트르산으로 가교된 pH 감응성 카르복시메틸셀룰로오스 하이드로겔의 흡수 특성]

초록

In this study, pH-responsive hydrogels were prepared from carboxymethyl cellulose (CMC) using epichlorohydrin (ECH) or citric acid (CA) as crosslinkers to compare their swelling and water-retention properties. CMC solutions containing varying concentrations of either crosslinker (0–1.5% (w/w)) were oven-dried to form their corresponding films, which were used to prepare the hydrogels. As observed, all solutions exhibited shear-thinning behaviors, with viscosity increasing more significantly for the ECH-containing solution than for the CA-containing one. Fourier-transform infrared analysis confirmed the formation of an ether bond between the ECH and CMC hydroxyl groups and an ester bond between the CA carboxyl groups and CMC hydroxyl groups. The zeta potential for all prepared hydrogels shifted from near neutral at pH 3 to strongly negative at pH 11. Concurrently, the swelling capacity decreased sharply at a crosslinker concentration of more than 0.5%, while the centrifuge retention capacity (CRC) increased. The ECH-crosslinked hydrogels exhibited slightly lower swelling but higher CRC compared with the CA-crosslinked ones. These results indicate that the pH-responsive performance of CMC-based hydrogels can be tailored for smart-absorbent applications by adjusting the crosslinker type and concentration. © 2025, Korean Technical Assoc. of the Pulp and Paper Industry. All rights reserved.

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