Despite several excellent properties including low shrinkage, good chemical resistance, curable at low temperatures and the absence of byproducts or volatiles, epoxy resins are susceptible to ultra violet (UV) damage and their durability is reduced substantially when exposed to outdoor environments. To overcome this drawback, UV absorbers have been usually used to decrease the rate of UV degradation. In this present study, the effects of UV light on the chemical, mechanical and physical properties of cured epoxy structure, as well as the effect of an organic UV absorber, Tinuvin 1130, on the epoxy properties were investigated. Chemical changes in a cured epoxy system as a result of the presence and absence of Tinuvin 1130 were determined using Fourier transform infrared spectroscopy (FT-IR) analyses. The effect of Tinuvin 1130 on the surface morphology of the epoxy systems was also investigated by scanning electron microscopy (SEM) imaging. Additionally, the glass transition temperatures (T_g) before and during UV radiation were measured. After an 800 h UV radiation, mechanical test results revealed that the lack of the UV absorber can lead to a ~30% reduction in tensile strength. However, in the presence of Tinuvin 1130, the tensile strength was reduced only by ~11%. It was hypothesized that the use of Tinuvin 1130, as an organic UV absorber in the epoxy-amine system, could decrease the undesirable effects, arising from exposure to UV light.

The aim of this study is to find a suitable substitution for diglycidyl ether bisphenol A (DGEBA) to avoid the devastating side effects of bisphenol A. Vanillin, an aromatic compound, was used as a renewable material to synthesize a bio-based epoxy resin. The structure of the vanillin-based epoxy resin was confirmed by Fourier transform infrared spectroscopy (FT-IR) analysis. The major drawback of bio-based epoxy resins is their poor mechanical properties preventing them from competing with petroleum based epoxy resins such as DGEBA. Herein, a prepared calcium nitrate solution as an inorganic accelerator was used to accelerate the curing reaction of bio-based epoxy resin which reduced curing times as well as improving significantly the mechanical properties e.g., tensile strength, pull-off strength, and Izod impact strength. Differential scanning calorimetry (DSC) analysis was used to investigate the curing process and thermal properties of the vanillin-based epoxy resin with and without inorganic accelerators and also DGEBA without accelerators. The results showed that in the presence of 2 wt% inorganic accelerator, the initial onset curing temperature of vanillin-based epoxy resin was reduced from 60.1 °C to 8.5 °C, while the initial onset curing temperature of DGEBA was 55.8 °C. In addition, tensile strength and Izod impact strength of the vanillin-based epoxy system in the presence of inorganic accelerators increased in comparison to the DGEBA system. Moreover, in order to study the effect of inorganic accelerators on the toughness of the synthesized vanillin-based epoxy resin, fracture surfaces from Izod impact strength tests were observed using scanning electron microscopy (SEM) which confirmed improving mechanical properties.

This review addresses the current potential of two-dimensional (2D) transition metal dichalcogenide (TMD) nanomaterials for multi-functional polymeric nanocomposites. The properties of TMDs, characterization techniques, the applicability of different synthesis methods along with the surface treatment/modification of TMDs, are comprehensively examined by largely focusing on TMD/polymer nanocomposite preparation. Moreover, a vast range of nanocomposite properties, including mechanical/tribological properties, thermal stability/flame retardancy, and electrical/electronic properties, was investigated. The incorporation of TMDs in both thermoplastic and thermoset matrices can lead to the improvement of the aforementioned properties as reported by many studies in the literature. TMDs can thus possibly be considered not only as a liable reinforcement for polymers to induce multi-functionalities to nanocomposites but also a good hybridizing agent for other types of nano reinforcements. Potential opportunities offered by TMDs in composites/nanocomposites have opened up new horizons in a vast range of applications in different fields, including transportation, electrical/electronic, filtration and biomedical. This review has also compiled publications on the research and developments of TMDs and TMD composites/nanocomposites, from 1970 to the present, with the special focus on molybdenum disulfide (MoS₂) and tungsten disulfide (WS₂).

Metal–organic frameworks (MOFs) have emerged as a new class of crystalline nanomaterials with ultrahigh porosities and high internal surface areas.