Thermo-mechanical and viscoelastic behavior of microwave-processed sisal and banana hybrid composite laminates

The growing demand for sustainable and high-performance materials has led to the exploration of natural fiber-reinforced composites. However, the optimal manufacturing techniques for enhancing their mechanical and thermal properties are still under-explored. The present study addresses this gap by utilizing microwave-based processing at 2.45 GHz to fabricate hybrid composites of linear low-density polyethylene (LLDPE) reinforced with sisal and banana fibers. The thermo-mechanical characterization was used to explore the performance of the various fabricated samples, such as LLDPE, sisal/sisal, banana/banana, and sisal/banana composite laminates. FTIR analysis was performed to study interfacial interactions within composites. The sisal/banana hybrid composite laminates demonstrated impressive properties with an Archimedes density of 0.9684 g/cc and exhibited superior mechanical and dynamic properties. Specifically, the sisal/banana hybrid composite had the highest tensile strength, flexural strength, and impact strength of 22.82 MPa, 15.87 MPa, and 254.35 J/m, respectively. Additionally, it had a storage modulus of 851.1 MPa. The Cole–Cole plot illustrated the heterogeneity within the composites, highlighting the strong interfacial adhesion between the fiber and the matrix. The fracture analysis of specimens shows that almost all specimens exhibit failure at the top location, likely due to the progressive formation of a structural feature known as a chap. Scanning electron microscopy analysis of fractured surfaces shows that fiber pullout, voids, and broken fibers are the common failure modes.

Graphical Abstract