Pengaruh Arah Serat Komposit Sandwich Hybrid Serat Sabut Kelapa Carbon Fiber Metode Vacuum Infusion

Abstract

Currently, the use of industrial materials heavily relies on non-renewable metals, necessitating alternative materials that are more cost-effective and of high quality. Composites possess better mechanical properties, strength, and rigidity than metals, making them suitable alternatives. To create new and more useful materials, composites combine two or more materials at a macroscopic level, or directly visible level. Composites consist of a matrix and fibers; the matrix functions to bind the fibers and keep them in place. The matrix also has properties that allow it to easily change shape according to design. Typically, resin materials act as adhesives for fiber materials and strongly hold the fiber batts together. Natural and synthetic fibers are used in composites. Natural fiber composites are highly effective in reducing the use of non-renewable and petroleum-based materials. Natural composites consist of various materials such as hemp, bamboo, banana, palm, and others. Fiber reinforcement composites are used instead of glass. The conducted research is experimental and aims to determine the tensile strength and characteristics of coconut husk fiber-carbon fiber sandwich composites. In this study, sandwich composite specimens were created using vacuum infusion techniques. The production of sandwich composite specimens involved coconut husk fiber in 0°, 90°, random alkalization, and random non-alkalization fiber orientations, with an epoxy resin matrix. The coconut husk fibers were soaked in a NaOH solution for 30 minutes. Afterward, the fibers were arranged according to the desired fiber orientations. The manufacturing of the sandwich composites involved carbon fiber - coconut husk fiber - carbon fiber, which was then processed using the vacuum infusion method. The highest tensile strength value obtained was 54.07 MPa in the 90° fiber orientation. The lowest tensile strength value was 33.23 MPa, which was achieved with the 0° fiber orientation. This is influenced by the effect of fiber orientation aligned with the direction of load and force, resulting in greater tensile strength. Conversely, a transverse fiber orientation with the direction of load and force leads to lower tensile strength. The micro-observation of the composite characteristics revealed numerous imperfect fiber-matrix interface bonds. This can be seen from the presence of fiber failures, such as fiber pullout.