Modification of natural rubber composite by way of in situ growth for UV-shielding property

Titanium dioxide nanoparticles (nano-TiO₂) and silicon dioxide (SiO₂) could endow the natural rubber (NR) with great UV-protection. However, their application in UV-resistant rubber remains challenging due to the poor compatibility with NR matrix and the photocatalytic activity of nano-TiO₂. Polydopamine (PDA) is a novel melanoid bionic material with free radical trapping function, which has strong light-absorbing properties and protects the NR matrix from free radical damage. Herein, PDA was introduced to the surface of NR (NR-PDA), then Nano-TiO₂ and SiO₂ were grown in-situ on the surface of PDA under acidic media to generate an inorganic shell layer. The prepared composites NR-PDA-TiO₂-SiO₂ have enhanced mechanical properties and excellent UV-shielding ability. The tensile strength is up to 9.78 MPa, which is about 1.2 times higher than that of NR, while its tensile strength retention after UV irradiation is up to 96.15%, which is 2.4 times higher than that of unmodified NR. This effective approach will particularly extend the service life of rubber products and expand the application of NR in UV-shielding materials.