Tough and recyclable carbon-fiber composites with exceptional interfacial adhesion via a tailored vitrimer-fiber interface
Md Anisur Rahman, Menisha S. Karunarathna, Christopher C. Bowland, Guang Yang, Catalin Gainaru, Bingrui Li, Sungjin Kim, Vivek Chawla, Natasha Ghezawi, Harry M. Meyer, Amit K. Naskar, Dayakar Penumadu, Alexei P. Sokolov, Tomonori Saito
Abstract
Carbon-fiber-reinforced polymers (CFRPs) offer improved energy efficiency in aerospace and automobile applications due to lightweight and mechanical robustness but face challenges with limited recyclability and frequent fiber-polymer delamination caused by inadequate interfacial adhesion. Here, we report an effective design of tough and closed-loop recyclable carbon-fiber-reinforced vitrimers (CFRVs) with exceptional interfacial adhesion through the synergy of a boronic ester-modified commodity polymer, multidiol cross-linker, and diol-functionalized carbon fibers (CFs). The dynamic covalent bonding between the vitrimer and fiber interface results in 43% higher interfacial adhesion than that of CFRVs with pristine CFs. Moreover, CFRVs with diol-CFs exhibit ∼731-MPa tensile strength, 26% higher than unmodified CFRVs and 49% higher than conventional epoxy CFRPs. Importantly, the dynamic boronic ester exchange enables CFRV closed-loop recyclability, repairability, fast thermoformability, self-adhesion, and multicycle processability without compromising mechanical performance. The designed dynamic fiber-matrix interaction will open up a new paradigm of multifunctional CFRPs while providing a path toward closed-loop structural materials.