Bioepoxy based advanced lightweight hybrid composites from hemp fibers: Towards greener production

Abstract

Over the past few decades, the widespread use of composite materials has become prominent, particularly following the industrial revolution. In response to environmental concerns, natural fiber polymer composites have found extensive applications, notably in the automotive industry and various versatile applications. However, pure natural fiber polymer composites face challenges in matching the performance of synthetic fiber-reinforced polymer composites. To address this issue, natural fibers are hybridized with synthetic fibers to enhance the performance characteristics. In this study, hemp fibers were hybridized with Innegra fibers through a stacking sequence and subjected to weathering. Both the weathered and unweathered composites underwent mechanical, thermal, and viscoelastic analysis to assess their performance under harsh environmental conditions. The mechanical analysis revealed that the tensile strength of the composite with Innegra as the skin layer was 76.56 MPa, reducing to 67.73 MPa after the weathering process. The flexural strength showed values of 111.01 MPa and 101.61 MPa before and after the weathering process, respectively. Thermomechanical analysis indicated that pure hemp composites exhibited lower thermal expansion at 1.45%, with the composite featuring hemp fibers in the outer layer performing better at 2.34% compared to hybrid composites. Additionally, SEM images demonstrated good interfacial adhesion between fibers and the matrix. Overall, the results suggest that the developed composites have the potential for use in lightweight semi structural applications.