Tensile Strength and Microstructure Analysis of Coconut Frond Fiber Composite Based On Polyester Resin With Fiber Orientation Variation

Abstract

 The exploration of eco-friendly composite materials incorporating agricultural biomass waste has intensified to reduce reliance on synthetic components. This study evaluated the tensile mechanical behavior and micromorphological failure characteristics of coconut frond fiber-reinforced composites in a polyester matrix, using five fiber orientation angles (0, 30, 45, 60, and 90 degrees). Specimens were fabricated using the hand lay-up method and tested for tensile strength following ASTM D638, followed by microstructural failure characterization using Scanning Electron Microscopy (SEM) under ASTM E986. Results show that fiber orientation had a significant, non-linear effect on the mechanical response of the material. The lowest average tensile strength was found in the 30-degree specimens at 8.53 MPa, caused by dominant interlaminar shear stress at the fiber-matrix interface. In contrast, the best mechanical performance occurred at 60-degree orientation, reaching an ultimate tensile strength of 22.18 MPa, driven by effective mechanical interlocking between fibers and efficient load transfer. SEM observations confirmed that brittle fracture dominated the failure mode, accompanied by micro-voids, interfacial debonding, and fiber pull-out. These findings indicate that coconut frond fiber composites oriented at 60 degrees hold strong potential as a lightweight, environmentally friendly structural alternative to synthetic timber boards.