Sulfur Quantum Dots for Natural Rubber: Vulcanization and Enhanced UV Aging Resistance

Incorporating sulfur quantum dots (SQDs) into natural rubber (NR) latex produces eco-friendly nanocomposites with enhanced UV resistance. SQDs simultaneously function as nanovulcanizing agents, UV blockers, and fluorescence enhancers. The nanocomposite containing 3 phr SQDs (N-3) exhibited a tensile strength of 2.23 MPa and an elongation at break of 1221.31%, attributed to a continuous cross-linked network formed via sulfur radical reactions (cross-link density: 116.50 × 10–4 mol cm–3). After 72 h of UV exposure, N-3 retained 74% of its initial tensile strength, markedly outperforming pure NR. Density functional theory (DFT) calculations confirmed the radical-trapping mechanism of SQDs, with an alkyl radical binding energy of 88.26 kcal mol–1. Furthermore, SQDs/NR-based triboelectric nanogenerators (S-TENGs) achieved high electrical output (48.01 V, 0.52 mW m–2), enabling self-powered biomechanical monitoring. This work advances the understanding of SQDs’ role in rubber vulcanization and antiaging and promotes their application in high-performance elastomers, flexible electronics, and energy harvesting.