Eco-friendly Superabsorbent Polymers from Bambusa vulgaris and Musa paradisiaca L.: A Comparative Study

Abstract

Background: Developing bio-based superabsorbent polymers from agricultural residues may provide a renewable route for producing water-absorbing cellulose-derived materials. Aims: To isolate cellulose from Bambusa vulgaris and Musa paradisiaca L. stem wastes, synthesise carboxymethyl cellulose (CMC)-based superabsorbent polymers through alkaline carboxymethylation and citric acid crosslinking, and evaluate the effects of synthesis parameters on water absorbency and viscosity. Study Design: Experimental comparative study involving controlled variation of sodium hydroxide concentration, monochloroacetic acid concentration, reaction time, reaction temperature, and particle size, with comparative evaluation of Bambusa vulgaris and Musa paradisiaca L. cellulose-derived CMC-based superabsorbent polymer. Place and Duration of Study: Nepal, July 2025 – February 2026. Methodology: Cellulose was isolated from B. vulgaris and M. paradisiaca L. stem wastes and converted into CMC through alkaline carboxymethylation using sodium hydroxide and monochloroacetic acid. The resulting CMC was crosslinked with citric acid to prepare CMC-based superabsorbent polymers. The effects of sodium hydroxide concentration, monochloroacetic acid concentration, reaction time, reaction temperature, and particle size on water absorbency were evaluated using the centrifuge method. Viscosity was measured using a Brookfield viscometer. Fourier-transform infrared spectroscopy and X-ray diffraction were used to characterise the functional groups and structural properties of the synthesised materials. Results: B. vulgaris showed higher absorbency and viscosity than M. paradisiaca L. The maximum water absorbencies were 74.82% for B. vulgaris and 68.76% for M. paradisiaca L. Fourier-transform infrared spectroscopy analysis showed characteristic –OH, –CH₂, –COO⁻, and C–O–C vibrations, consistent with carboxymethylated cellulose. X-ray diffraction analysis indicated predominantly amorphous structures in the CMC-based materials. The synthesis parameters and particle size influenced the water absorbency and viscosity of the resulting materials. Conclusion: Stem wastes of B. vulgaris and M. paradisiaca L. can serve as renewable feedstocks for producing bio-based superabsorbent polymers. B. vulgaris showed greater potential for producing materials with higher water-absorption and viscosity properties. Further optimisation of crosslinking conditions, biodegradability, and mechanical stability is recommended to improve their practical applicability.