Water superabsorbent composites of dialdehyde cellulose from various cellulosic sources: a comparative study

In the context of global water shortages, there is an urgent need to implement effective strategies for the management of water resources. The objective of our research is to synthesize superabsorbent polymers to efficiently utilize water resources in agriculture, with a particular focus on the impact of cellulose sources and properties on absorption capacity. A hybrid superabsorbant polymer (SAP) hydrogel was prepared by combining 5% (wt) cellulose pulps or their dialdehyde cellulose (DACs) with a poly (acrylic co-itaconic) copolymer acid through radical chain polymerization. The crosslinker used was N,N-methylene-bis-acrylamide (MBA), while potassium persulfate (KPS) was employed as the polymerization initiator. The bleached pulps, DACs, and superabsorbent composites (SAPs) hydrogels were characterized by FTIR, XRD, SEM, and TGA. The results showed that an increase in the periodate equivalent relative to the glucose residue resulted in an increase in aldehyde content and a decrease in crystallinity, accompanied by a change in the morphological properties of the obtained oxidized fibers. Moreover, SAPs containing dialdehyde cellulose exhibited greater porosity compared to SAPs without DACs. The swelling capacity of the hydrogels was determined using the tea bag method. The SAPs of DAC extracted from banana fibers demonstrated a higher water absorption capacity of 1300 g g⁻¹ compared to other SAPs due to the specific hydrophilic properties of the DAC derived from banana, especially its lower crystalline index.

Graphical Abstract