Thermal, Structural and Biodegradability Properties of Bio-Based Kenaf/PMMA Composites Reinforced with Chitosan

Abstract

This study investigates the incorporation of chitosan into kenaf/poly(methyl methacrylate) (PMMA) hybrid composites to enhance thermal, physical, and biodegradability properties. Kenaf fibers were alkali-treated, ground, and mixed with PMMA, while chitosan was incorporated at 10 g and 20 g concentrations in PMMA. The composites were fabricated via hot pressing method and characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), Thermogravimetric Analysis (TGA), water absorption and soil burial analyses. FTIR spectra revealed intensified –OH and –NH stretching peaks (~3351 cm-1), indicating strong hydrogen bonding and compatibility between chitosan and the PMMA matrix. SEM micrographs showed improved fiber–matrix adhesion with reduced void formation in the 20 g chitosan composite. TGA results demonstrated enhanced thermal stability, with char residue increasing from 1.43% (0 g chitosan) to 2.07% (20 g chitosan) and degradation temperatures shifting toward higher ranges. Water absorption tests showed a reduction of up to 28% in moisture uptake in chitosan-modified samples compared to the control. Soil burial analysis confirmed improved biodegradability, with weight loss increasing by nearly 35% after 30 days for the highest chitosan-loaded sample. EDX analysis further confirmed successful chitosan incorporation with increased oxygen and carbon elemental signals. Overall, chitosan significantly improved the interfacial bonding, thermal stability, durability, and environmental responsiveness of the kenaf/PMMA hybrid composites, making them viable candidates for sustainable applications such as biodegradable panels and green furniture.