Influence of Ultraviolet Radiation on the Morphological and Mechanical Properties of Carbon Fiber-Reinforced Polymers

It is clear that modern carbon fiber (CF) manufacturing methods will go beyond luxurious or limited-use of CF products toward a vast and unlimited commercial evolution of CF uses in multiple engineering applications. This expansion of the unlimited use of CF will be a major challenge for researchers to provide in-depth information to define the mechanical properties of CF products and the extent to which these properties are affected by various environmental factors. Therefore, defining the carbon fiber-reinforced polymer (CFRP) properties under different loading and environmental conditions is critical for extreme operating conditions. Sunlight, heat, and humidity have become a research focus to explore the impact of these parameters on the morphological and mechanical characteristics of the CFRP. This article investigates the influence of sunlight expressed in terms of UltraViolet (UV) light on the morphological and mechanical properties of two different layups of CFRP through tensile testing. The fracture modes were classified based on the ASTM standards to categorize the changes of CFRP with respect to the duration of UV exposure. Furthermore, the observed weight reduction of the exposed CFRP is related to the changes in the mechanical properties. The outcomes show that there is a reduction in tensile strength to approximately 18% for the 45° layup setting and 21% for the 90° layup setting by increasing the UV exposure time to 160 hr. Moreover, the fracture mode was also affected by the UV exposure time, showing more tendency of explosive catastrophic fracture in the center of the specimen at various places, which is known as XMV fracture mode according to ASTM standards.