In-situ growth strategy of ZIF-8 nanocrystals on carbon fibers achieved high-efficient interface enhancement

The unique imidazole bridge structure of ZIF-8 nanocrystals makes it flexible and low elastic modulus, which can withstand more flexible crystal deformation and have superior bearing capacity and anti-wear effect. In this work, an in-situ growth strategy of ZIF-8 nanocrystals on the surface of carbon fibers (CFs) was used for the enhancement of interfacial combination and out-of-plane properties between CFs and Poly(hexahydrotriazine)s (PHT) matrix. The introduction of ZIF-8 nanocrystals functionalized CFs to disperse and transfer more load and energy, and the interface performance between two phases were characterized via mechanical and tribological tests. The results indicated that the tensile strength of ZIF-8 grafted on CFs increased due to the improved rough surface, bonding area and active chemical groups of CFs. The fracture mechanism of ZIF-8 based composites were investigated by morphology observation on the interface. In addition, the wear rate of ZIF-8 based composites reduced by 43.7% when compared to neat CF. The improvement of mechanical and tribological properties depends on the introduction of ZIF-8 which improves the interfacial adhesion between CFs and resin matrix, and further facilitates the load transfer from interface to CFs.