An overview of recent advances in polymer composites with improved UV-shielding properties

Owing to their competitive price, ease of processability, and rust resistance, polymers are the most extensively used materials in everyday life. However, consistent exposure to ultraviolet (UV) radiation can lead to the degradation and discoloration of polymeric materials. Various polymer composites containing inorganic and organic nanoparticles (NPs) have been developed to improve the UV-shielding properties of neat polymers. However, the most used UV-shielding inorganic NPs are prone to photocatalytic processes, leading to further polymer chain degradation. To overcome this challenge, organic NPs have been used; however, they easily agglomerate, decreasing the UV-shielding performance of the polymer composites. Herein, we critically report the fundamentals of the UV-shielding mechanism and the synthesis methods, surface modification, and characterization of the most important inorganic and organic UV-shielding NPs. We then summarize the various processing techniques used to disperse NPs in polymer matrices to obtain polymer composites with improved UV-shielding properties. Finally, we propose a broader understanding of how the NP characteristics, their interaction with polymer matrices, and the various processing methods affect the UV-shielding performance of the obtained polymer composites. In addition, various applications of inorganic and organic NPs-containing UV-shielding polymer composites have been reported.