Mechanical performance of hybrid lignin/glass fibre epoxy bio-composites

Hybrid bio-composites integrating renewable lignin and synthetic glass fibres have emerged as sustainable alternatives to traditional composites, addressing the environmental concerns associated with non-degradable synthetic materials. This study investigates the synergistic effects of lignin and glass fibres on the mechanical properties of glass fibre-reinforced polymer composites (GFRPs). Composite samples were fabricated with varying weight percentages of lignin (0%, 2%, 4%, and 6%) and glass fibres (1%, 2%, and 3%), adhering to ASTM standards for tensile, bending, and impact tests. The findings reveal that lignin significantly enhances the tensile and bending properties at optimal concentrations. However, excessive lignin (>4 wt%) reduces the composite's performance due to interface disruptions. Flexural strength exhibited a similar trend, with a peak at lower lignin concentrations. Numerical simulations using ABAQUS software showed good agreement with experimental results, validating the computational approach. The results of this study demonstrate that lignin can serve as an effective reinforcing agent in hybrid composites, improving mechanical properties while reducing environmental problems.