Photocatalyzed Covalent Interfacial Modification of Sulfhydryl‐Modified Graphene Oxide for Enhanced Mechanical and Anti‐Aging Natural Rubber Composites

ABSTRACT Thermal oxidative aging, the primary cause of natural rubber degradation during storage or use, can be effectively mitigated by designing covalent cross‐linking interfaces between nanofillers and rubber, which provides a simple and highly efficient way to prolong service life. In this work, the active thiol groups were modified on the surface of graphene oxide (GO, radial dimension: ~10 μm) through photochemical grafting to facilitate the covalent interface cross‐linking effect between GO and natural rubber (NR). The photocatalyzed thiol‐vinyl‐mediated click reaction between –SH and –C═C– of NR was established at the interface. The thiol groups modified GO (GS), used as filler, were uniformly dispersed in the NR matrix and formed beneficial covalent interactions with the NR chains. The obtained GS modified NR (NR/GS) composite exhibited excellent mechanical properties and aging resistance in air after the vulcanization process. The tensile strength of the NR/GS composite could reach up to 26.99 MPa, while its heat resistance index reached as high as 176.6°C. Additionally, the composite exhibited significantly improved resistance to thermal oxidizing aging properties. This synthetic strategy provides a robust method for the improvement of covalent interfacial interactions between NR and the GS sheets during the latex stage.