Epoxy nanocomposites holding molybdenum disulfide decorated with covalent organic framework: All-in-one coatings featuring thermal, UV-shielding, and mechanical properties

Abstract

Engineering polymer nanocomposites with a broad spectrum of functions are pivotal in real-life applications. However, characteristics of nanocomposites, such as mechanical, thermal, chemical stability, UV-shielding, and weathering properties, have conflicting requirements. Thus, the concurrent integration of these properties into one coating system has proved to be challenging. As such, herein, inspired by the nacre integration of organic and inorganic materials, nanohybrid units composed of molybdenum disulfate (MoS2) decorated with covalent organic frameworks (COFs) were developed, bestowing the desired multifunctionality on the coating. A broad spectrum of characterization techniques, including XRD, XPS, TEM, DMTA, Tensile, QUV, and contact angle, were utilized to certify the successful synthesis of the nanohybrid and evaluate the thermal/mechanical properties of the corresponding polymeric nanocomposites. As a result, with a small loading of the nanohybrid (0.15 wt%), the storage modulus, cross-linking density, glass transition temperature, and tensile strength of the loaded coatings were enhanced substantially by 33%, 230%, 42%, and 225%, respectively. Moreover, the thermal analysis demonstrated that after 3 min of exposure to flame, the loaded coatings had a 12% lower temperature compared to the neat epoxy coatings, implying that the nanocomposite coatings acted as a thermal barrier. Furthermore, the weathering test showed that after 170 h exposure to UV light, the generated nanocomposites experienced only a minor color change. Such an all-in-one design not only expands the durability of coatings but also cuts down maintenance and repair costs.