Asian Journal of Research in Chemistry

Hydrogels have demonstrated an array of potential as a medium throughout the last century for a range of applications. Synthetic polymers currently dominate hydrogel fabrication research and industry. It turns out that these synthetic polymers are not biodegradable posing serious environmental problems therefore finding a sustainable substitute for polysaccharide-based high-performance hydrogel synthesis is imperative. Utilising biopolymers produced from polysaccharides to produce high-performance hydrogels reduces environmental pollution and manufacturing costs. The most common organic polymer found in nature, cellulose has a wide range of applications despite being poorly soluble in most organic solvents including water. A cellulose pulp was produced by pre-treating the waste papers with double alkali and acid hydrolysis, which eliminated the lignin and hemicellulose, respectively. This pulp was then characterised using a Scanning Electron Microscope (SEM) and Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR). The cellulose pulp’s FT-IR spectrum showed no peak at 2957, 2886, 1513, and 1430 cm^-1, confirming that there was neither lignin nor hemicellulose present. The resulting cellulose pulp was dissolved in an 8:6.5:8 weight percent solution of sodium hydroxide, urea, and thiourea to form a self-standing cellulose hydrogel without the requirement for a cross-linker. Carboxymethyl cellulose (CMC) was then added as an agent for gelling and refrigerated at -20°C. ATR-FTIR and SEM were used to characterise the uncross-linked cellulose hydrogel (UCH) that was generated. To improve the mechanical, swelling, and stability properties of UCH, cross-linked cellulose hydrogel (CCH) was made by crosslinking the UCH with glutaraldehyde (GA). The CCH was evaluated using FT-IR and SEM-EDX. The analysis of ATR-FTIR and SEM micro-image data added to the evidence supporting the existence of a chemical cross-linking reaction between GA and cellulose. A preliminary test was carried out utilising the tea-bag method at a predetermined time to investigate the impact of cellulose alteration on each hydrogel’s capacity to swell.