Enhancement of Saline Absorbency in CMC/Starch-Based Superabsorbent Polymers by Incorporation of Sodium Bicarbonate; [중탄산나트륨 첨가에 따른 CMC/전분 기반 고흡수성 고분자의 염수 흡수 특성 향상]

초록

Carboxymethyl cellulose (CMC)/cationic starch (CS)-based superabsorbent polymers (SAPs) were prepared with different sodium bicarbonate (NaHCO3) contents to improve saline absorption behavior while maintaining structural stability. The effects of NaHCO3 addition on network structure, swelling behavior, rheological properties, and mechanical stability under load were systematically investigated. A small amount of NaHCO3 (2.5 wt% on CMC and CS) significantly enhanced saline absorption, which was attributed to partial relaxation of electrostatic interactions between CMC and cationic starch and the formation of additional diffusion pathways. SEM analysis revealed the development of internal porous structures induced by weak foaming associated with CO2 generation during drying. However, increasing NaHCO3 content led to a reduction in gel strength, gel fraction, absorption under load (AUL), and centrifuge retention capacity (CRC) due to decreased effective crosslink density. These results demonstrate that controlled NaHCO3 addition provides an effective strategy to balance saline absorption performance and mechanical stability in eco-friendly polysaccharide-based SAPs. © 2026 Korean Technical Assoc. of the Pulp and Paper Industry

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