Thermal, Morphological, and Structural Properties of Biodegradable Unripe Banana Starch (Musa sapientum L.) Composites Reinforced with Pineapple Leaf Fibres, (Ananas comosus L. Merr.)

Growing interest in the creation of biodegradable composites is a result of the growing demand for sustainable substitutes for synthetic polymers. The main aim of this study is to characterize and contrast biodegradable composites composed of unripe banana starch reinforced with pineapple leaf fiber. Two composite formulations were created: Sample B (10 g of unripe banana starch, 5 mL of glycerol, 100 mL of distilled water, and 5 g of fiber) and Sample A (10 g) of unripe banana starch, 5 mL of glycerol, 100 mL of distilled water, and no added fiber). 
Strong intermolecular interactions were confirmed by Fourier Transform Infrared Spectroscopy (FTIR) analysis, as evidenced by the carbonyl (C=O) and hydroxyl (-OH) absorption peaks present in both samples. Significantly, Sample B showed more intense peaks, which suggested that the fiber and starch interacted better and had a stronger hydrogen bond. Surface structure variations were clearly visible using scanning electron microscopy (SEM). While Sample B displayed better fiber dispersion, stronger adhesion between the fiber and starch matrix, 
with a more uniform texture (signs of improved stress distribution). Sample A had a rough, brittle appearance with visible microcracks. Changes in the material's elemental composition were verified by Energy Dispersive X-ray Spectroscopy (EDX). The fiber was successfully incorporated into the matrix, as evidenced by Sample B's higher carbon content. Sample B had higher crystallinity, according to X-ray diffraction (XRD) analysis, suggesting that fiber reinforcement had improved molecular alignment and increased structural integrity. Overall, the results suggest that pineapple leaf fibre significantly improves the structural, morphological, and mechanical characteristics of the composite. These OKUNZUWA and UKWESAN/BJPS, 2(2), December, pg. 13-28 (2025) 14 enhancements support its potential as a sustainable and eco-friendly alternative to conventional polymers. With better fibre-matrix bonding, improved molecular structure, and greater mechanical stability, these biodegradable composites hold promise for use in areas such as sustainable packaging, lightweight construction, and environmentally responsible consumer products.