Synthesis and Characterization of Superabsorbent Cellulose-Based Hydrogel for Agriculture Application

Hydrogels are 3D network formed by linear (or branched) hydrophilic polymer molecules that are chemically or physically crosslinked. Hydrogels can absorb a prominent amount of water and biological fluids and release them at a controlled rate. This study deals with the synthesis and characterization of carboxymethylcellulose sodium salt (CMCNa) and hydroxyethyl cellulose (HEC)-based biodegradable hydrogels using citric acid (CA) as a crosslinker. The chemical analysis of synthesized hydrogels is performed using Fourier transform infrared spectroscopy. The cellulose nanocrystals (CNCs) are synthesized by an acid hydrolysis process and are incorporated into the hydrogel matrix and the effects of CNCs on hydrogel properties are assessed. The effects of the CA on hydrogels swelling properties are also studied and about 600% swelling is observed for the hydrogel synthesized using 2% of the CA crosslinker. Using CNCs as reinforcing agents for hydrogel composites decreases the tensile strength of hydrogels because of poor CNC dispersion within the hydrogel matrix is observed that can be seen in the scanning electron microscope images. The optimum use of crosslinkers and proper distribution of CNCs in the hydrogel matrix can provide a promising hydrogel material that can absorb and release water in a controlled manner to improve utilization of available water resources for agricultural applications.