Structural modification of pineapple leaf fiber by Chemical and Mechanical methods

Abstract

Pineapple leaf fibre (PALF) emerges as a sustainable alternative to synthetic fibres, yet its inherent hydrophilicity and biocompatibility limitations necessitate surface modifications for broader applications. This study investigates the effects of chemical treatments—alkali (NaOH) and bleaching (H₂O₂)—on PALF’s structural, mechanical, and crystalline properties. Fibers extracted from Ghanaian pineapple leaves underwent decortication, urea pretreatment, and variable NaOH concentrations (2M and 6M), followed by peroxide bleaching. Fourier Transform Infrared Spectroscopy (FTIR) confirmed the effective removal of lignin and hemicellulose in chemically treated samples, while X-ray Diffraction (XRD) revealed enhanced crystallinity (peaks at 2θ ≈ 22° and 16°) due to delignification. Mechanical processing retained amorphous content, underscoring the superiority of chemical methods. Alkali-treated PALF exhibited tensile strengths up to 1620 MPa, though excessive NaOH compromised fiber integrity. Bleaching improved whiteness but reduced tensile strength, highlighting trade-offs. The findings demonstrate that optimized chemical treatments (2M NaOH, 60% H₂O₂) enhance PALF’s compatibility with polymer matrices, enabling applications in composites, aerospace, and biomedical fields. This work advances sustainable material science by valorizing agricultural waste while addressing critical gaps in natural fiber modification.