Fabrication and characterization of coir/carbon-fiber reinforced epoxy based hybrid composite for helmet shells and sports-good applications: influence of fiber surface modifications on the mechanical, thermal and morphological properties

Coconut-coir, a natural fiber, strong and lightweight, abundantly in India and Vietnam, can be an excellent choice to produce polymer composites. Due to the higher specific modulus and durability, these composites have a myriad of applications. This article provides a novel experimental research study on the fabrication and investigation of mechanical as well as thermal behavior of coir fiber/woven-carbon fiber/epoxy resin hybrid composite. The composite samples were formulated with distinct fiber weight percentages viz. 30%, 20%, and 10% using the vacuum bagging technique. Mechanical behavior (tensile, compressive, flexural, and impact strength) and thermal behavior (Thermogravimetric analysis) of coir fiber/carbon fiber/epoxy resin hybrid composites were studied according to the ASTM standards. Moreover, Scanning Electron Microscopy (SEM) was performed to examine the morphological characterization of tensile fractography specimens and analyze the properties of the fiber/matrix bonding of the surface before and after alkaline treatment. The treated fiber shows good matrix binding and less fiber pull-out as compared with untreated fibers. The result also revealed that the hybrid composite has more robust properties under mechanical loading than single fiber-reinforced composite.