Investigating the thermo-mechanical and UV-shielding properties of a nano-porous Zr(IV)-type metal-organic framework (MOF) incorporated epoxy composite coating

Abstract

In the present work, the effects of UIO-66 nanoparticles on the epoxy-polyamide composite coating thermal resistance, mechanical features, and weathering (UV) resistance were explored. The nanoporous UIO-66 particles were developed by the common solvothermal procedure. The final particles were identified by Brunauer–Emmett–Teller (BET), Fourier transform infrared (FT-IR) spectroscopy, and Raman analysis. Also, the thermal properties, as well as the mechanical characteristics of the epoxy nanocomposites loaded with 0.2, 0.4, 0.8, and 1.2 wt% of the UIO-66 particles were studied by thermal gravimetric analysis (TGA), tensile, and dynamic mechanical thermal analysis (DMTA) methods. Besides, the UIO-66 particles containing composite coatings UV resistance at various loadings were studied after 500 h exposure to UV-A irradiation (320–400 nm range) via spectrophotometer analysis, contact angle test, surface roughness analysis, and micro-hardness investigation. BET surface area analysis illustrated a surface area (SA) of 820 m2 g−1 for the constructed metal-organic framework (MOF) particles. TGA outcome exhibited that the temperature related to the weight loss of 80% in the presence of nanoparticles (NPs) increased up to approximately 60 °C. On the other hand, the tensile analysis outcomes indicated that the toughness and strain values related to the breaking of the film increased about 2.1 and 1.5 times (at 1.2 wt% filler loading), in comparison with the pure (un-filled) epoxy matrix, respectively. The DMTA test outcomes demonstrated significant improvements of the UIO-66 particles loaded epoxy coatings storage modulus in the glassy region (especially at 1.2 wt%) and crosslinking density (especially at 0.8 wt%). Results proved that the thermal and mechanical characteristics of the nanocomposite were promisingly improved compared to the pure epoxy. Results proved significant epoxy film UV-shielding properties enhancement in the presence of 1.2 wt% UIO particles.