DOI: https://doi.org/10.55373/mjchem.v27i5.110

Keywords: Oil palm empty fruit bunches; N, N'-methylene bisacrylamide; glutaraldehyde; crosslinking agent, hydrogel

Abstract

The structure, swelling behaviour, and stability of hydrogels derived from oil palm empty fruit bunches (OPEFB) hemicellulose are strongly influenced by the type and amount of crosslinkers used. This study investigates the effects of varying amounts of N,N'-methylene bisacrylamide (MBA) and glutaraldehyde (GA) on the swelling, physicochemical and thermal properties of hemicellulose-based hydrogels. Hemicellulose was extracted from OPEFB using microwave-assisted alkali treatment at 130°C for 30 minutes and was subsequently used to prepare hydrogel with different amounts of MBA and GA as crosslinking agents. The results demonstrated that hydrogels crosslinked with 0.01 g MBA exhibited the highest swelling ratio at 615%, attributed to the formation of dense and rigid network structures. In contrast, GA-crosslinked hydrogels achieved a swelling ratio of up to 1.64 (164%) and exhibited more balanced swelling behaviour, maintaining flexibility while ensuring structural stability. Field emission scanning electron microscopy showed a more uniform and dense network structure in MBA-crosslinked hydrogels. Furthermore, thermogravimetric analysis demonstrated enhanced thermal stability in the presence of MBA, with higher decomposition temperatures compared to GA-crosslinked samples. These findings highlight the greater effectiveness of MBA as a crosslinking agent in improving the properties of hemicellulose-based hydrogels, supporting their suitability for agricultural applications such as soil conditioners or controlled-release fertilisers.