Challenges and Opportunities for Aging of Fiber‐Reinforced Polymer Under Intensive Solar Radiation

ABSTRACT The outdoor application of fiber‐reinforced polymer (FRP) composites can reduce their lifespan owing to the intensive solar radiation. The ultraviolet (UV) light and massive heat from the solar energy would trigger photo‐ and thermo‐degradative reactions in polymers, leading to the breakage (chain scission) and recombination (crosslinking) of molecular bonds in the polymer chemical structures. Consequently, this degradation process can cause aesthetic and mechanical deterioration, including yellowing, surface cracking, increased brittleness, and loss of mechanical strength. This review paper focuses on the engineering aspects, discussing the main degradation mechanisms in polymeric materials, regulation of mechanical properties in both neat polymers and FRP composites, and protective measures to resist intensive solar radiation.