Covalent organic framework (COF)-decorated NH2-functionalized MXene sheets for thermomechanical and UV-shielding performance of epoxy nanocomposite coatings

Designing a multi-purpose epoxy nanocomposite with promising mechanical and weathering properties is yet a challenge to be explored. Meeting all above mentioned properties in one nanocomposite requires a rational design of hybrid nanomaterials benefiting from their synergistic effect. To this end, a robust imine-based COF was synthesized on an MXene substrate, forming an inorganic-organic assembly as filler for a multi-functional epoxy coating. As a proof of concept, the tensile strength of the loaded coating was almost twice the unloaded one, confirming the efficient stress transfer due to mechanically robust MXene and compatibility improvement of the hybrid assembly in the presence of the COF. Furthermore, the physical barrier of MXene, along with the nitrogen-rich structure of COF, resulted in efficient thermal insulating properties of the fabricated nanocomposite coatings. Moreover, the weathering test illustrated that the conjugated structure of the COF enhanced the epoxy film weathering stability after 7 days of UV exposure, which is promising among competitors. This high yield, facile processing, and rational design provide new insight into the application of MXene-conjugated COF in epoxy nanocomposite coatings.