Papers by Keyword: Infrared Spectroscopy

Abstract: The work presented in this article demonstrates that mixing clay from clay soils with polyethylene aggregates is possible for the production of stabilized earth bricks. We manufactured raw stabilized clay bricks, which we fired at 900°C with 0% and 7% polyethylene aggregate content. We characterized them physically, chemically, thermally, and mechanically using standard norms and equipment. Our physical characterization showed that the density of the material decreases when loaded with 7% polyethylene aggregates and, conversely, our mechanical characterization showed that compressive strength decreases in the raw state and increases in the fired state with the addition of the load. Thermal characterization (ATG, DSC, and DTG) shows that the mixture with 7% polyethylene aggregates contains free water, kaolinite, illite, and quartz with a high silt content, indicating the presence of both clay and polyethylene aggregates. Chemical characterization (FTIR) shows that the clay + polyethylene aggregate mixture has the presence of an intense peak at 1002.72 cm-1 and a band at 757 cm-1 relating to the elongation and torsion vibrations of the Si-O bonds respectively for the loaded and unloaded raw bricks. The bands at 1877.71 and 2850.07 cm-1 correspond respectively to the stretching vibrations of the Si-O-Si and Si-O-Al bonds and can be attributed to the -C-O groups of alcohols and esters. In addition, we have an intensity band between 785.20 and 943.86 cm⁻¹ that can be attributed to the -O-H groups of alcohols, allowing us to observe the influence or presence of polyethylene in the mixture when heated to 900°C.

Abstract: Studying the spectroscopic properties of nanomaterials and nanoparticles is essential for developing nanomaterial science and nanotechnology. Spectroscopic properties of nanoparticles of biological origin, especially pathogenic nanoparticles such as viruses, became actual after the Covid-19 pandemic, causing economic, human and social harm. Known spectra of the utmost atoms, molecules, and compositions are well used for identification. In this paper, we provide a concise review of the experimental results obtained from advanced spectroscopy techniques by various scientific groups and demonstrate the possibility of using spectra of viruses to detect and identify diseases caused by pathogens. Raman, ultraviolet (UV), and infrared (IR) spectroscopy methods for experimental study of viral materials are considered.

Abstract: Investigated the synthesis of polyphenylene sulfide in the environment of an aprotic polar solvent based on p-dichlorobenzene and p-dibromobenzene according to the nature comonomer rating. Infrared spectroscopy and thermogravimetric analysis of the obtained samples are presented.

Abstract: The paper studies the influence of nanodispersed aluminum and silicon oxides on the structural, physico-chemical and mechanical characteristics of calcium-magnesium bentonite deposits of the Republic of Tatarstan, in order to determine the optimal concentrations of the nanomodifier, and to improve the performance of respective materials. It was found that nanomodification of bentonite increases the strength of samples after firing by more than 1,5 times, the adsorption index by 20–25 %. The optimal concentration of nanoparticles was determined by changing the properties. The methods of Brunauer-Emmett-Teller (BET), x-ray phase analysis and infrared spectroscopy show an increase in the specific surface area, a change in the phase composition of the annealed samples, the intensity and position of the characteristic absorption bands, as well as the chemical bond silicon-oxygen in bentonite, modified by nanoparticles of aluminum and silicon oxides of similar nature.

Abstract: We tested stability of 43 selective sorbents, covering the widest range of functional groups, efficiency of sorption, method of production, and which are theoretically useful for sorption of cesium, strontium, cobalt, arsenic and actinoids. We present 3 of them: A = TiO₂, B = Al₂O₃ and C = MxH(TiO)₄(SiO4)₃ . z H₂O. In first testing, sorbents were exposed to the model solution of boric acid for 168 hours, in which they were mixed in a closed container with a rotator. After the exposure, sorbent solutions were filtered and analysed by spectroscopic techniques (Infrared Spectroscopy (IR), Raman Spectroscopy (RS) and newly by Scanning Electron Microscopy (SEM), combined with Energy Dispersive Spectroscopy (EDS)). Exposed spectra were compared with spectra of new, non-exposed sorbents. In second testing, sorbents were exposed to gamma radiation for 12 days with total dose 666 ± 43 kGy, produced by cobalt bomb and analysed by same techniques. The aim of our testing was to find out how sorbents behave in model boric acid solution and what effect has the gamma radiation on sorbent spectra and to analyse sorbents by SEM with EDX.

Abstract: In the present paper we study the effect of complexation in linear negatively charged polyelectrolytes with different alkali ions. With combination of IR-spectroscopy, X-ray diffraction and nanocalorimetry, we attempted to explain unusual solubility, crystallinity and thermal stability of these polymers. The increase of thermal stability and insolubility in water in series of semi-crystalline polysalts as K⁺ ≤ H⁺ <Na⁺ was explained by effectiveness of formation of chelating complex. Insoluble in water sodium salt shows the highest thermal stability of crystal phase up to . In contrast, well soluble in water amorphous lithium salt does not self-organize in chelating complex and is presented in ionic form.

Abstract: The paper presents the effect of ground glass (GG) particles on the water absorption and tensile properties of epoxy. The GG particles contents in the epoxy were 0, 5, 10 and 15% (by volume). The results showed that the GG particles in the epoxy changed the water absorption behaviour from Fickian to non-Fickian. At the GG particles content of 15%, the equilibrium water uptake increased almost double, but the diffusion rate decreased by about 85% compared to the unfilled epoxy. In dry condition, the tensile strength tended to decrease with increasing the GG particles content, by about 11% at the GG content of 15% compared to that of the unfilled epoxy; however, the elastic modulus tended to increase linearly with the GG content. In wet condition, up to the GG content of 10%, the tensile strength decreased by about 77% compared to that of the unfilled epoxy; however, at the GG particles content of 15%, the tensile properties were improved.

Abstract: Understanding the process of water oxidation, especially intermediate species, represents an important step toward gaining a mechanistic understanding of new emerging catalysts. The aim of this study is exploring the process of water oxidation and electrolyte orientation under external potential when using an emerging water oxidation catalyst, CoB_i, in sodium borate (NaBi) buffer using in situ attenuated–total-reflection Fourier transform infrared spectroscopy (ATR-FTIR) spectroscopy. CoB_i is generated via electrodeposition from aqueous solutions containing borate and Co²⁺. IR spectra were obtained for CoB_i films under applied potentials supporting water oxidation catalysis. The spectra of water and CoB_i on ZnSe/Cr/Au electrode surfaces change in intensity and their slope depends on the potential, which is rarely reported. The appearance of new bands at certain potentials is interpreted in terms of the potential-dependent re-alignment of water and borate molecules both from the film and electrolyte. A superoxide surface intermediate at 1027 cm^-1 was observed in both thin and thick films. It is proposed to be Co (III)OO*H bridging and relates to a fast water oxidation process. The chemical structure of the intermediate species is proposed finally.

Abstract: The effect of monoethylene glycol (mEG) acting as chain extender in polypropylene glycol (PPG-4000) and 4,4ʹ-diphenylmethane diisocyanate (MDI) reaction was investigated. Polyurethane elastomers (PUR) were changed from flexible to rigid materials by varying the mEG content. Results show that Shore A and D hardness values trend to increase with increasing mEG content. It appears that increasing the chain extender content increases the hard segment content in the polyurethane structure. Moreover, increasing the mEG content increases Young’s modulus and the tensile strength of PUR, while elongation at break decreases. The chemical structure of the hard segment of PUR was characterized by Infrared (IR) spectroscopy. IR spectra exhibited the bands typical for PUR consisting of –NH, CH₂– and C=O groups. The spectra reveal a few interactions between the polymeric chains that appear to be responsible for the shift of transmittance peak and decrease of some peak intensity. This may be due to the hard segment aggregating more to form domains in the PUR when mEG content was increased.

Abstract: This study used an optimized mixture of red mud (RM), rice husk ash (RHA), diatomaceous earth (DE), and water glass solution (WGS) with silica modulus of 2.5 to produce geopolymer-based material. The geopolymer product was tested engineering properties which are in good agreement of ASTM requirements for building materials. For microstructure, the geopolymer samples were characterized by using Fourier-transform infrared spectroscopy (FTIR) and focused on evaluation on formation of aluminosilicate network in the ternary-blended geopolymer. The results showed that tetra-silicates or acid silicic (Si (OH)₄ or H₄SiO₄) dissolved and reacted with the iron oxide (Fe₂O₃) in RM and DE to form the oligomer precursors of sialate-O-Si-O-Al-O-, sialate-siloxo-O-Si-O-Al-O-Si-O-, sialate-disiloxo-O-Si-O-Al-O-Si-O-Si-O-, tetra-silicate [SiO₄]^4-, and tetra-aluminate [AlO₄]^4-. The formation of sodium alumino-silicate iron hydroxide polymeric network were easily detected by vibrational modes of –T–O–T– and –T–O–Na units (T refers to tetrahedral such as that of Si or Al) and of –OH and H–O–H. As well as, there were appearances of the membered ring or chain structural units of geopolymers.