Mechanical and morphological evaluation of jute fiber reinforced epoxy composites for sustainable structural and automotive applications

This study investigates jute fibre reinforced epoxy composites fabricated using a controlled vacuum bag moulding process, with emphasis on establishing reliable structure property relationships relevant to sustainable engineering applications. To address limitations in earlier jute/epoxy studies such as generic claims, limited processing transparency, and weak correlation between impact behaviour and fracture mechanisms laminates containing 5, 10, 15, 20, and 25 wt.% jute fibre were produced and systematically characterized. Tensile strength and modulus increased with fibre content, reaching peak values of 95 MPa and 4.5 GPa at 20 wt.%, while reduced elongation at break indicated enhanced stiffness. Flexural strength and modulus exhibited similar trends, attaining maximum values of 150 MPa and 4.8 GPa, respectively, consistent with improved load transfer and crack-bridging mechanisms. Hardness and low-velocity impact energy absorption were also optimized at 20 wt.% fibre loading due to strengthened fibre matrix interfacial bonding and more uniform stress distribution. A decline in mechanical performance at 25 wt.% was attributed to fibre agglomeration, micro-void formation, and localized interfacial debonding. Scanning electron microscopy revealed matrix-dominated fracture at low fibre contents 5 to 10 wt.%, optimal dispersion and interfacial integrity at intermediate contents 15 to 20 wt.%, and severe clustering at higher loading. These findings identify 15 to 20 wt.% jute fibre as the optimal range for achieving a balanced combination of stiffness, strength, and impact resistance, supporting potential application in lightweight, non-critical structural and automotive components.