Preparation and application of UV absorber functionalized siloxane: A transparent and high ultraviolet shielding performance polydimethylsiloxane film

Through a silane-hydride addition reaction, the ultraviolet (UV) absorber 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole (BHEM) was introduced into the hydrogenated polysiloxane (PMHS) side chains, resulting in the preparation of a UV-absorber-functionalized siloxane (PM/BH). The effect of the molar ratio of vinyl to Si H in the grafting reaction on the molecular characteristics and rheological behavior of PM/BH was analyzed. PM/BH was then used in the fabrication of polydimethylsiloxane (PDMS) films, successfully producing a PDMS composite film (PD-PM/BH) with both high transparency and excellent UV shielding performance. Further investigation was conducted on how different grafting reaction molar ratios of PM/BH affected the mechanical properties, transparency, and UV shielding performance of the composite films. The results indicated that all composite film samples maintained high transparency and outstanding UV shielding capabilities, with visible light transmittance exceeding 85 %. The PM/BH prepared by grafting at a vinyl-to-Si-H molar ratio of 0.1 imparted the composite film with the best mechanical properties.