Green Interfacial Engineering via Carbon Dot Grafting for Strong and Aging-Resistant Fiber–Elastomer Interfaces

Fiber-reinforced elastomer composites are indispensable structural materials for transportation and industrial applications, yet their performance is fundamentally limited by inefficient stress transfer across fiber-elastomer interfaces and the lack of efficient and sustainable interfacial engineering approaches. Herein, we report a green interfacial engineering strategy based on carbon dot (CD) grafting to regulate surface chemistry and morphology of polyethylene terephthalate fibers. A microwave-assisted reaction simultaneously generates and covalently anchors CDs onto the fiber surface, constructing functionalized and roughened surfaces. Experimental results combined with theoretical calculations reveal the molecular interactions between CD-derived functional groups and the impregnation layer, elucidating the mechanism of interfacial reinforcement. The engineered interface enables more efficient stress transfer and markedly enhanced interfacial adhesion while retaining the radical-scavenging capability of CDs, which improves thermo-oxidative aging resistance. By integrating CD-grafted fibers with an eco-friendly impregnation system, the composites achieve markedly enhanced interfacial performance, with a 137% higher peel strength compared with unmodified fibers, highlighting the effectiveness of CD grafting for green processing. This work establishes an efficient interfacial engineering strategy for fiber-reinforced elastomer composites, offering both mechanistic understanding and practical guidance for designing durable and sustainable fiber-elastomer interfaces.