The present study investigates the synthesis and characterization of undoped and Fe-doped (with 2%, 4%, and 6 wt%) CeO2 thin films using a facile spray pyrolysis method. X-ray diffraction analysis revealed the polycrystalline nature with a fluorite structure (FCC) and confirmed the successful doping of iron into the ceria lattice without secondary phases. Raman analysis confirmed that Fe doping in CeO2 primarily affects lattice vibrations by creating oxygen vacancies, leading to changes in shifts in Raman phonon modes. Scanning electron microscopy (SEM) showed presence of cracks in both undoped and Fe-doped CeO2 thin films, increasing Fe concentration reduced the number and size of cracks. Energy dispersive X-ray spectroscopy (EDS) analysis indicates the successful incorporation of Fe into the CeO2 lattice. A decrease in crystallite size was observed with Fe incorporation in all sample using Transmission Electron Microscopy analysis (TEM). Optical measurements showed that the bandgap of the material decreased from 3.11 eV to around 2.80 eV with increasing Fe doping, this reduction in bandgap was attributed to the formation of oxygen vacancies (Vo) resulting from the doping. Magnetic behavior of the samples was studied using Vibrating Sample Magnetometer (VSM) which show a ferromagnetic property of films were explained based on oxygen vacancies and a reduction in the valence state of Ce+4 to Ce+3. The photocatalytic degradation rate demonstrated improved degradation rates with increasing iron doping level up to 6%, attributed to the presence of Fe3+ ions, which promote electron/hole pair generation.

Continuing our investigation into the synthesis and applications of new epoxy resins, we developed a new octafunctional epoxy resin based on octaglycidyl ether tetra-aniline para methylene dianiline (OGTAPMDA) and investigated its rheological and thermal properties after being reinforced with carbon nanotubes. After manufacturing the resin, we measured its viscometric and rheological properties with an Ubbelohde-type capillary viscometer and a RHM01-RD Haaks rheometer, respectively. To create new nanocomposite materials, the resin was cross-linked thermally with methylene dianiline (MDA) in the presence of carbon nanotubes (CNTs). The thermogravimetric study results allowed us to assess and understand the nature of the heat degradation of these new macromolecular composites. It demonstrates that the thermal stability of the base matrix increases in proportion to the fraction of CNTs. It also shows an increase in the density of the nanocomposites when large amounts of CNTs are utilized, resulting in an increase in polymer viscosity. Rheological investigations of our nanocomposites, on the other hand, show that their thermal and rheological properties are similar. This describes how CNT particles improve the thermal and rheological properties of nanocomposites. The produced nanocomposites' morphology was also examined using the scanning electron microscopy (SEM). The images obtained demonstrate that the carbon nanotubes are evenly distributed in the polyepoxide matrix.

In this paper, the synthesis of a new trifunctional sulfur and phosphorus epoxy architecture based on hydroxy diphenyl sulfone bis para-ester phosphoric triglycidyl ether (TGEHDSEP) is presented. The viscometric properties of the synthesized resin using an Ubbelohde type capillary viscometer were investigated and were thermally crosslinked using the hardener methylene dianiline (MDA). The viscosity values of the new trifunctional epoxy resin TGEHDSEP increased as the pre-polymer mass concentrations increased, as expected, and as the sample temperature increased, the viscosity of the system (TGEHDSEP/ethanol) decreased. A new nanocomposite composed of the prepared resin, TGEHDSEP, and carbon nanotubes (CNT) was developed using a variety of formulations to optimize the rheological behavior and thermal stability of the epoxy matrix. The effect of the CNT filler in admixture with the TGEHDSEP/MDA system in this series of formulations on the nanocomposites rheological properties was studied. The rheological and thermal properties of the formulated materials were assessed using the RHM01-RD Haaks rheometer and the thermogravimetric analysis (TGA) in the dynamic regime, respectively. The results showed that the G′ (storage modulus) and G′′ (loss modulus) of various nanocomposites increase as the filler CNT content increases. Over the entire frequency range studied, the storage modulus G′ is much higher than the loss modulus G′′ for methylene–dianiline crosslinked nanocomposites formulated with varying percentages of CNT. The storage modulus G′ of all prepared nanocomposites increases as the percentage of CNTs increases. These results also show that the addition of carbon nanotubes to the epoxy matrix improves its thermal properties significantly. The morphology of the prepared nanocomposites, analyzed by scanning electron microscopy (SEM), varies significantly with the percentage of carbon nanotube filler incorporated into the studied matrix, and the carbon nanotube filler is uniformly distributed in this epoxy resin. Finally, we utilized the Materials Studio software package to investigate the mechanical and thermal conductivity properties of TGEHDSP and single-walled carbon nanotube (SWCNT). The material exhibited the following mechanical properties: Young's modulus: 7.1508 GPa, shear modulus: 2.6169 GPa, bulk modulus: 8.9116 GPa, Poisson's ratio: 0.3663. Additionally, its compressibility is approximately 105.9918 TPa. On the other hand, the epoxy resin, TGEHDSP, performs relatively well as a heat conductor among epoxy-based materials, while SWCNT's high thermal conductivity highlights its exceptional heat transfer capabilities, characteristic of nanoscale structures.

ABSTRACT The ability of Natural Muscovite Clay (NMC) to adsorb Methylene Blue (MB) as a dye widely used in the industrial sector was investigated, and the adsorption process was interpreted at the molecular scale through computational modelling. After the characterisation of NMC, the effect of adsorbent mass (5–40 mg), contact time (1–60 min), solution pH (3.7-11.78), stirring speed (100–900 rpm), initial MB concentration (15–80 mg.L-1), and temperature (293.15-333.15 K) on the adsorption efficiency were inspected in the batch mode. The results showed that the basic pH, high stirring speed, and low temperature were the favourable conditions for the MB adsorption onto NMC. The adsorbed quantity Qe,exp of MB dye was found to be 59.828 mg.g-1 for the initial concentration of 80 mg.L-1 at 293.15 K using an NMC mass of 20 mg. The obtained values of thermodynamic parameters suggested that the removal of the MB dye was exothermic, and physical in nature. The adsorption isotherm of the MB/NMC system was analysed according to the statistical physics approach using the Levenberg-Marquardt iterating algorithm and showed a best fitting with the monolayer model with one energy. The analysis of kinetic data showed that the external diffusion and intra-particle diffusion steps have occurred simultaneously and contributed to the control of the adsorption rate of the MB dye onto NMC. The computational modelling of interactions between the MB molecule and the muscovite, kaolinite, and quartz minerals were examined according to the Monte Carlo simulation (MCS) and showed an ability of the dye molecule to be adsorbed onto the surface of these minerals. The calculated adsorption energies ranged between -2.23×104 and -1.10×104 Kcal.mol-1 reflected the stability and the spontaneity of the adsorption process. So, the surface of clay minerals (i.e. muscovite and kaolinite) was more favourable to the adsorption of the MB molecule.

Cyclotriphosphazenes, a variety of inorganic rings together with a curing ingredient, 4,4′-methylene dianiline (MDA), are mainly used to enhance the thermal conductivity and mechanical characteristics of epoxy resin (DGEBA). Three DGEBA@MDA, HGCP@MDA, and thermosets were produced, and their curing behaviors were investigated. Using a molecular dynamics (MD) approach, the impact of cyclotriphosphazene on the characteristics of DGEBA composites is thoroughly explored in this paper. Results indicated that the glass transition temperatures (Tg) of DGEBA containing HGCP had slightly decreased compared to DGEBA. With the addition of HGCP to DGEBA, epoxy resin (DGEBA@HGCP@MDA) has a high thermal conductivity of 0.215284 W/m·K, with an increase of 116.04% more than pure DGEBA (0.185524 W/m·K). Moreover, the DGEBA@HGCP@MDA composite has high mechanical strength with a specific Young’s modulus of 5.4902 GPa. In order to forecast and analyze certain performances directly associated with the microstructure characteristics of the various cross-linked resin systems and their composite materials, an MD simulation approach will be quite valuable.

Objective of this study is to develop a highly effective and durable phosphorus based epoxy resin as anticorrosive coating material for carbon steel in 3% NaCl medium. The hexaglycidylN,N ',N ''-tris (4,4 '-ethylene dianiline) phosphoramide (HGTEDPA) was characterized using spectral methods. The anticorrosive formulation (HGTEDPA-MDA) was synthesized using HGTEDPA curing with 4,4 '-methylenedianiline (MDA). The formulation (HGTEDPA-MDA) coated steel specimens were exposed to UV radiation for a specific durable (189 days) and durability of the formulation was tested along with its inhibition effectiveness. The anticorrosive property of the formulation was evaluated using electrochemical (electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP)) methods. Results showed that HGTEDPA-MDA coating improved the corrosion resistance value even after exposing 180 days to the UV radiation. PDP study suggested that HGTEDPA-MDA before and after UV radiations acted as mainly anodic and cathodic type of inhibitor, respectively. The EIS and PDP results were corroborated with density functional theory (DFT) and molecular dynamic simulations (MDS) methods and a reasonable good agreement was observed. DFT study revealed that HGTEDPA-MDA interacts with the metallic surface using donor-acceptor interactions. MDS study revealed that HGTEDPA-MDA spontaneously interacts with steel surface and adsorb using horizontal orientation.

Adsorption is a major basic and applied phenomenon in many scientific disciplines. In particular, the design of adsorbents to remove pollutants from wastewater requires advanced knowledge of adsorption isotherms, which are useful tools to identify physicochemical factors that control adsorption performance. Recent modeling of adsorption isotherms has focused on the use of statistical physics. Here, we review the major adsorption isotherm models based on statistical physics. We discuss steric, energetic, and thermodynamic parameters.

The evaluation of the anti-corrosive performance of polymer composite reinforced with zinc phosphate (DGEBA-DAA-ZP) acts as an effective anti-corrosive coating for 15CDV6 steel in 3wt% NaCl at different exposure times ranging from 60, 120, and 180 days in a salt spray chamber. EIS study revealed that composite formulation (DGEBA-DAA-ZP) acts as strong interface coating. Results showed that magnitude of charge transfer resistance (Rct) and coating resistance (Rpore) gradually decrease on increasing the exposure time. After 1 h exposure time, DGEBA-DAA-ZP formulation exhibited Rct and Rpore values of 16.6 kΩ cm2 and 6.16 kΩ cm2, respectively. However, after 180 days exposure, the Rct and Rpore values lower to Rct and Rpore to 4.21 kΩ cm2and 2.25 kΩ cm2, respectively. MD simulation study demonstrated that DGEBA-DAA-ZP adsorbed on the Cd surface using its flat orientation.

Several new epoxy monomers were synthesized from glycidylation of functional aromatic amines containing hydroxyl or thiol groups. The epoxy monomers were triglycidyl-2-aminophenol, triglycidyl-2-aminothiophenol, tetraglycidyl-1,2-phenylenediamine and tetraglycidyl-4-methyl-1,2-phenylenediamine. The characterization of the epoxy monomers was carried out by FTIR and 1H NMR spectroscopy. Rheological properties of solutions of the epoxy monomers in ethanol were evaluated using an advanced rheometer. The effect of solution concentration and temperature on the viscosity of the epoxy solution was evaluated. The shear rheology study at various temperatures of the epoxy resins solutions in ethanol was carried out on solutions with concentrations ranges form 0.5 to 5 wt% and temperatures (20–70 °C). The results revealed that the tetra-functional epoxy resins behave as Newtonian liquids and its viscosity is independent on the shear rate. However, the solutions of tri-functional epoxy resins are non-Newtonian liquids, and their viscosities are shear rate dependent. The activation energy of the epoxy monomers was calculated from the Arrhenius equation using solution with concentrations ranges of 0.5–5 wt%.