Investigating the Synergetic Effect of Ultraviolet Radiation and Elevated Temperature on Mechanical and Thermal Properties of Glass Fiber–Reinforced Plastic Pipes

Glass fiber–reinforced plastic (GRP) pipe was aged in different environmental conditions to investigate its morphological structure, mechanical properties, and thermal behavior. In the oil field service, the durability of nonmetallic pipes is questioned considering exposure to different harsh operating conditions such as high temperature, ultraviolet radiation, and rain. The influences of different environmental condition parameters can affect the properties of GRP pipes and, consequently, impact their overall performance and service life. In this study, samples subjected to similar conditions of the desert field revealed a noticeable tendency of wet crude oil at sufficient water cut to cause degradation to the GRP tubing material. Scanning electron microscopy and thermographic analysis of samples subjected to long-term exposure in the aquifer water revealed the formation of salt crystals. The two-phase crude oil/water system under nonultraviolet radiation samples showed no significant diffusion by the chemical media. The tensile testing showed a slight change in tensile strength with aging in wet crude. In addition, samples exposed to ultraviolet radiation have revealed an evident change in modulus results, in which the polymer matrix of samples subjected to ultraviolet radiation and elevated temperature is most affected. Our results show that the mechanical properties of the composite pipe samples aged in wet crude were more deteriorated than those aged in harsh water, and for surface pipes ultraviolet radiation has an impact on the stability of the polymer matrix after a long exposure period.