Construction of an epoxy composite coating with exceptional thermo-mechanical properties using Zr-based NH2-UiO-66 metal-organic framework (MOF): Experimental and DFT-D theoretical explorations

In this study, for the first time, the influence of the nanoporous Zr-based NH2-UiO-66 metal-organic frameworks (MOFs) on the tensile strength and fracture toughness of the epoxy coating was investigated. In addition, the impacts of the UiO particles' functionality (i.e., NH2 or GMA) on the MOFs/epoxy interfacial bonding and nanoparticles dispersion quality in the epoxy resin were examined by the tensile test, dynamic mechanical thermal analysis (DMTA) and field emission-scanning electron microscope (FE-SEM). The NH2-UiO-66 and GMA-UiO-66 MOFs chemical structures were investigated by FT-IR, BET, and FE-SEM approaches. The FE-SEM investigation of the fracture morphology (at the cross-section of the epoxy composites) and EDS-mapping analysis results evidenced the uniform dispersion of the Zr-based GMA-UiO-66 particles in the epoxy matrix. TGA achievements revealed that by introducing 0.2 wt% GMA-UiO-66 and NH2-UiO-66 nanoparticles into the epoxy coating, the thermal stability of the coating was improved about 80% and 48%, respectively compared with the neat epoxy sample. The tensile test results evidenced about 80% and 70% improvements in the energy at the break, and 64% and 41% improvements in the tensile strength, of the GMA-UiO-66 and NH2-UiO-66 loaded nanocomposites, respectively. The final results declared that the GMA-UiO-66 could effectively toughen the epoxy coating much higher than the NH2-UiO-66 particles.