Derivatographic Studies Research Articles

In Ukrainian

Double phosphates compounds may possess catalytic, magnetic, electrophysical, non-linear optical properties and are used as monocrystals or polycrystals, ceramics etc. The tailor-made synthesis of double phosphates of alkali and multivalent metals is the basis for the in-depth research and investigation of physical and chemical properties, composition and structure of the compounds to be used for the development of new materials for multi-purpose use. Episodic syntheses of compounds MI3MIІMIV(PO4)3, MI2MIIMIV(P2O7)2, MI2MII(PO3)4 and МІMІІ4(РО4)33 (where МI – Li, Na, K; МIІ – Mn, Co, Ni; MIV – Zr), were made from various starting materials by the sintering method. After all, the selection of compounds for the synthesis of compounds of this type is a rather difficult task, often impossible. A systematic approach to the selection of starting reagents, temperature regime, interaction time between components are factors that can be adjusted and operated to achieve the target. The work used the method of solid-phase synthesis, after working out the synthesis method on the “model” Na2NiZr(P2O7)2. The synthesis was carried out starting from Na2CO3, NiO, CoO, ZrO2, ammonium hydro- and dihydrogen phosphate. The synthesis of compounds was carried out based on preliminary derivatographic studies of the passage of processes according to the corresponding reaction schemes. Completeness of synthesis stages was monitored at all stages using physico-chemical research methods. The DTA method confirmed the possibility of solid-phase synthesis of complex phosphate compounds that contain several transition metals – MINi2MIV(PO4)3 (where МI – Li, Na, K; MIV – Ti, Zr, Sn). The optimal temperature conditions for obtaining a number of phosphate compounds based on various starting substances for their synthesis have been found. The synthesized compounds were investigated by X-ray diffraction, DTA and IR spectroscopy, and their complete chemical analysis was carried out. The influence of a number of factors on the conditions of production of phosphate compounds of the MINi2MIV(PO4)3 (where МI – Li, Na, K; MIV – Ti, Zr, Sn) has been found. It can be assumed that the ionic conductivity in the synthesized compounds is of the “NASICON” type, and therefore the synthesized substances can be used as functional materials with valuable electro-physical properties.

Structural features and mechanism of crystallization of nanocomposites based on maleinated high density polyethylene and carbon black

The results of studying the structural features of nanocomposites by electron microscopy, X-ray diffraction analysis, derivatography and stepwise dilatometry are presented. The kinetic regularities of crystallization of nanocomposites based on Exxelor PE 1040-modified high density polyethylene HDPE* and carbon black (CB) are considered by the method of stepwise dilatometry: the dependence of specific volume on temperature. Dilatometric studies were carried out in the temperature range of 20–210 °C. The concentration of nanoparticles was varied within 1.0, 3.0, 5.0, 10, and 20 wt%. In the process of studying the temperature dependence of the specific volume of nanocomposites, it was found that a first-order phase transition occurs for HDPE* samples with 1.0–10 wt% CB content at 119 °C, and for a sample with 20 wt% CB at 115 °C. The study of the process kinetics of nanocomposites isothermal crystallization showed that, for nanocomposites with 1.0–10 wt% CB content, the mechanism of the process is characterized by the formation of a three-dimensional spherulite structure with continuously formed homogeneous and heterogeneous nucleation centers. A substantiated theoretical analysis and interpretation of the discovered regularities of the crystallization process and the growth mechanism of crystalline formations is given. Derivatographic studies of nanocomposites were carried out, according to which the features of changes in the thermal-physical properties of nanocomposites depending on the content of carbon black were established. The results of X-ray diffraction analysis of nanocomposites with 20 wt% carbon black content are presented, according to which there is a slight decrease in their degree of crystallinity.

SYNTHESIS OF ULTRA-HIGH MOLECULAR WEIGHT POLYETHYLENE WITH HIGH MELTING POINT IN OCTAFLUOROBUTANE MEDIUM

Ultra-high molecular weight polyethylene (UHMWPE) with a high melting point (Tm) up to 144°C was successfully obtained by suspension polymerization in 1,4-H-octafluorobutane medium initiated by Ziegler–Natta catalysts. This method makes it possible successfully to carry out polymerization at a temperature close to ambient one and an ethylene pressure close to atmospheric one. The resulting polyethylenes were characterized by IR spectroscopy, elemental analysis and derivatographic studies. Values of melting points and degrees of crystallinity of the synthesized polymers were obtained using these data.

SYNTHESIS AND RESEARCH OF SILICON-CONTAINING PHTHALOCYANINE

The aim of this study is to synthesize, and study a new form of dye based on phthalocyanine, a silicon-containing phthalocyanine pigment used as a dye for dye-sensitive solar cells, which are currently third generation solar cells as one of the energy source alternatives. To achieve this goal, a silicon-containing phthalocyanine pigment containing urea, phthalic anhydride and sodium fluorosilicate was synthesized and studied. Based on the results of IR spectroscopy, the reaction of pigment formation is proposed and the data of scanning electron microscopy is presented. Its differential thermal analysis, photodynamic analysis and its relationship with inorganic and organic solvents were also analyzed. The optical density of the pigment was analyzed on a V-5000 spectrophotometer at wavelengths with a spectral with from 320 nm to 1000 nm. The study was carried out in 5% and 20% solutions of dimethylformamide. The absorption peaks showed good absorption at wavelengths from 400 to 500 nm. Derivatographic studies of the obtained pigment show that the main weight loss occurs in the range 110-482 °C, at which 18.25% of the basic weight, or 3.21 mg of weight, is lost, which means that the pigment is thermally stable.

ЕFFECT OF IRON AND NICKEL DITHIOCARBAMATES ON THE PROPERTIES OF MODIFIED POLYURETHANES

The effect of modifiers - nickel bis(N,N-dimethyldithiocarbamate) (DTC-Ni) and iron tris(N, N-dimethyldithiocarbamate) (DTC-Fe) depending on their content on the structural peculiarities of polyurethane matrix based on polyoxytetramethylene glycol-1000 4,4’-diphenylmethane diisocyanate and 1,4-butanediol has been studied. The method of IR spectroscopy according to the results of NH groups’, C = O- and COC fragments’ association has shown the structuring effect of modifiers due to the PU matrix coordination. The processes of photolysis occurred as a result of exposure of PU under the conditions of the climate chamber have been also studied by IR spectroscopy method. The influence of modifiers and their content on the modified polyurethanes density has been investigated. The planar structure of DTC-Ni has shown to contribute to the density increase of modified PU as the result of polymer chain coordination, while the spherical structure of DTC-Fe - causes a density decrease due to steric hindrances in the implementation of H-bonds. Modification of polyurethanes with both nickel bis (N, N-dimethyldithiocarbamate) and iron tris (N, N-dimethyldithiocarbamate) as well as UV irradiation and moisture under the conditions of the climatic chamber contribute to the increase of water absorption. Studies of the strength properties of modified polyurethanes in comparison with the matrix under the conditions of the climate chamber have established the photosensitizing effect of nickel and iron dithiocarbamates. By studying the mass of samples of PU-DTС-Fe/Ni after extraction with dimethylformamide in the Soxhlet apparatus it has been found an increase in the level of gel fraction (0.29 - 1.58%) with increasing the modifier content, which confirms the presence of a network structure of modified PU due to radical processes taking place during destruction with the modifier participation. The influence of alkaline and acidic media on the destruction level of both modified polyurethanes and their analogues depending on the modifier content under the influence of climatic chamber conditions has been studied. Comparative derivatographic studies in air of weight loss of modified polyurethanes have confirmed the structuring and thermostabilizing effect of DTC-Ni on the PU matrix due to the probable difficulty of oxygen diffusion to the polymer volume, while the spatial structure of PU-DTC-Fe reduces the thermal stability.

Study on the Properties of Semi-Synthetic Motor Oil Castrol 10W-40 after Use in a Diesel Engine

The changes in operational and physico-chemical properties of original and used semi-synthetic motor oil Castrol 10W-40 before and after its use in a diesel engine have been investigated. Derivatographic studies were carried out to examine a thermal stability; IR spectroscopy was used to confirm the presence of oil aging products. The composition of the inorganic part of the studied semi-synthetic oils was established by X-ray fluorescence analysis.

Synthesis of composites glauconite/polyaniline doped phosphatic acid and their properties

Polyaniline (PAn) and composites of glauconite/polyaniline (Gl/PAn) were synthesized by chemical oxidation polycondensation of aniline with ammonium peroxodisulfate in aqueous solutions of different concentrations of phosphoric acid, namely 0.60 M or 0.80 M, or 1.65 M, or 3.30 M. The content of glauconite in the reaction mixture was1 g, and the ratio of aniline : glauconite was 1 : 1. The properties of synthesized samples are investigated using by modern physical methods of analysis. The physical analysis of samples properties has been carried out using a Dron-4-07 diffractometer (Cu Kα radiation; l=1.54060 A) in the reflection mode. Fourier-transform infrared (FTIR) spectrа of powders sample were recorded out using a NICOLET IS 10 ATR spectrophotometer in the mode of reflection, which was later transformed into transmission mode. Thermal properties of synthesized samples has been analyzed using Q 1 500-D Derivatograph in the temperature range of 20–900 °C under a heating rate of 10 о /min in the atmosphere of air (corundum crucibles; standard – Al 2 O 3 ; weight of samples – 100 mg). The electrical conductivity of the pelleted samples was determined by measuring their resistance in the sandwich type cells at a temperature of 20±1 о С using a Rigol DM 3 068 set of equipment for resistance measuring. It was found that with increasing by concentration of phosphate acid in the initial reaction mixtures, the crystallinity of polyaniline in samples of pure PAn increases, whereas in samples of composites of Gl/PAn, the polyaniline are preferably amorphous. Intermolecular interaction between the components of the composite is due to the formation of hydrogen bond. Comparison of the results of derivatographic studies showed that the thermal properties of composites depend on the content of glauconite. Thermal stability is higher in samples containing glauconite. It is established that the process of thermodestruction of composites is complex and multistage. Specific electrical conductivity of the received composites of Gl/PAn is less than in PAn samples synthesized at different concentrations of phosphoric acid. Keywords: polyaniline, glauconite, composite materials, structure, thermal analysis, electrical conductivity.

4-Methyl-2,2-dioxo-1H-2λ⁶,1-benzothiazine-3-carboxylic Acid. Peculiarities of Preparation, Structure, and Biological Properties.

In order to determine the regularities of the structure–analgesic activity relationship, the peculiarities of obtaining, the spatial structure, and biological properties of 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic acid and some of its derivatives have been studied. Using nuclear magnetic resonance (NMR) spectroscopy and X-ray diffraction analysis, it has been proven that varying the reaction conditions using alkaline hydrolysis of methyl 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylate makes it possible to successfully synthesize a monohydrate of the target acid, its sodium salt, or 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine. The derivatographic study of the thermal stability of 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic acid monohydrate has been carried out; based on this study, the optimal conditions completely eliminating the possibility of unwanted decomposition have been proposed for obtaining its anhydrous form. It has been shown that 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine is easily formed during the decarboxylation of not only 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic acid, but also its sodium salt, which is capable of losing СО2 both in rather soft conditions of boiling in an aqueous solution, and in more rigid conditions of dry heating. The NMR spectra of the compounds synthesized are given; their spatial structure is discussed. To study the biological properties of 4-methyl-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxylic acid and its sodium salt, the experimental model of inflammation caused by subplantar introduction of the carrageenan solution in one of the hind limbs of white rats was used. The anti-inflammatory activity and analgesic effect were assessed by the degree of edema reduction and the ability to affect the pain response compared to the animals of control groups. According to the results of the tests performed, it has been found that after intraperitoneal injection, the substances synthesized demonstrate a moderate anti-inflammatory action and simultaneously increase the pain threshold of the experimental animals very effectively, exceeding Lornoxicam and Diclofenac in a similar dose by their analgesic activity.

Developing ash-free high-strength spherical carbon catalyst supports

The possibility of using furfurol for the production of ash-free high-strength active carbons with spheroidal particles as adsorbents and catalyst supports is substantiated. A single-stage process that incorporates the resinification of furfurol, the molding of a spherical product, and its hardening while allowing the process cycle time and the cost of equipment to be reduced is developed. Derivatographic, X-ray diffraction, mercury porometric, and adsorption studies of the carbonization of the molded spherical product are performed to characterize the development of the primary and porous structures of carbon residues. Ash-free active carbons with spheroidal particles, a full volume of sorbing micro- and mesopores (up to 1.50 cm3/g), and a uniquely high mechanical strength (its abrasion rate is three orders of magnitude lower than that of industrial active carbons) are obtained via the vapor-gas activation of a carbonized product. The obtained active carbons are superior to all known foreign and domestic analogues and are promising for the production of catalysts that operate under severe regimes, i.e., in moving and fluidized beds.

Derivatographic studies of a nanocomposite based on polypropylene and DK1 nanogel

Derivatograms of a polypropylene (PP) composite containing 2, 4, and 10 vol % of DK1 are represented. Regardless of the crystallization method, all the DK1 materials under study undergo a thermal oxidative breakdown at 305–320°C. An increase in the volume content of DK1 from 4 to 10% leads to a shift of the depolymerization temperature to higher values, which is most probably attributed to the formation of crosslinked structures in the material. Owing to this, after heating to 500°C, the amount of the solid residue in the PP + 10 vol % DK1 material crystallized by rapid cooling achieves 62%.

Derivatographic studies of polyethylene containing a dispersed semiconductor

The tendencies of the changes in the physical-chemical characteristics of high-density polyethylene films and polyethylene composites with a volumetric content of TlInS2 ferroelectric-semiconductor of up to 10% are investigated with the help of the DTA method. The changes in the thermophysical characteristics of the analyzed composites are shown to be related to the structural changes of the polymer under the effect of the additive particles with different degrees of dispersion. At 5 vol % of TlInS2, the additive particles act as artificial nuclei of structure formation.

Increasing Cristobalitization and Mullitization in Fired Clays by Mechanochemical Activation and the Use of Al2O3- and SiO2-Containing Additives

Results of the x-ray phase and derivatographic studies of refractory clays activated mechanochemically by means of planetary, vibratory, and screw grinding techniques are reported. The activation makes it possible to enhance cristobalitization and mullitization of the fired clays and to use lower firing temperatures. Good results giving the same effect is reached using Al2O3 and SiO2-containings additives such as clays, oxidal, and nepheline syenite.

Derivatographic Studies of the Thermal Behavior of Some Salts

The possibility and necessity of conducting derivatographic studies for obtaining more complete and detailed information on thermal decomposition of some salts are demonstrated. The derivatographic data suggested hypotheses on the mechanisms of action of salts on combustion and carbonization of polymer materials.

Texture and structure of nickel‐molybdenum catalysts supported on alumina modified with sulfate and phosphate ions

AbstractA series of nickel‐molibdenum catalysts supported on alumina modified with sulfate and phosphate ions was studied. The studies involved texture evaluation measurements through N2 adsorption isotherms. Besides, IR spectroscopic and derivatographic studies were carried out. Results of the studies enable us to conclude that modification of the alumina support with the above ions leads to a significant decrease in its surface area and pore volume. Modification does not result in a change of the type of pores of the support, but in the change of their size dimention. The pores present on the surface of the catalyst have the shape of “ink‐bottles”. Modification with phosphate ions improves the thermal stability of the catalyst, whereas sulfate ions present on the surface of the catalyst undergo decomposition upon heating of the sample. Phosphate ions inhibit formation of aluminum molybdate, and instead form polymeric layer structures of phosphate on the surface of catalysts. Sulfate ions occur in the form of surface aluminum sulfate.

Structure and Texture of Nickel‐Molybdenum Catalysts on Alumina Support Modified with Fluoride or Chloride Ions

AbstractThe performed study involves measurements of a specific surface area via a BET method, of the pore volume, FT‐IR, and a derivatographic study of a series of Al2O3‐supported nickel‐molybdenum catalysts modified with fluoride and chloride ions. It was found that fluoride ions lead to a decrease in the specific surface area of catalysts, whereas chloride ions have a small effect on this parameter. Modification does not change the type of pores of the catalysts, yet it affects their size and increases concentration of OH groups adsorbed on the surface of the catalysts relative to the carrier and the unmodified catalyst. Addition of fluoride ions decreases the thermal stability of the catalyst, whereas chloride ions does not cause any change.

Derivatographic study of gas transport reactions in powder mixtures of iron with ammonium chloride

Derivatographic study of gas transport reactions in powder mixtures of iron with ammonium chloride

Isostructural phase transition in the cubic oxide pyrochlore Cd 2Nb 2O 7

X-ray, EPR and derivatographic studies of Cd 2Nb 2O 7 and Cd 1.98M 0.02Nb 2O 7 (M denotes an ion of transition metals or rare earths) were carried out in the temperature region from 295 to 800 K. The results show that the phase transition at T tr =319 K is isostructural. Above T tr, O 7 h → O 7 h, but the (NbO 6) n− and (CdO 8) n− coordination polyhedra become crystalographically, not metrically, more regular improving the stability of the pyrochlore structure.

Thioether glycidyl resins. VII. Products of condensation of bis(4‐mercaptophenyl)sulfide and bis(4‐mercaptophenyl)sulfone with epichlorohydrin

AbstractNew thioether glycidyl resins by condensation of bis(4‐mercaptophenyl)sulfide or bis(4‐mercaptophenyl)sulfone with epichlorohydrin were obtained by heterophase alkaline condensation in aqueous and isopropanol medium using sodium hydroxide. The detailed studies on their structures from elemental analysis and IR and 1H‐NMR spectra, physical and chemical properties, and curing conditions are presented. Thioether glycidyl resins compositions were also prepared using curatives typical for epoxy resins and after curing they were characterized from derivatographic, thermomechanical, and mechanical studies.

Non-isothermal derivatographic study of MoO 3-C and Co 3O 4-C binary systems

High temperature reactions between graphite (C) powder and MoO 3 or Co 3O 4 were investigated in a static air atmosphere using a MOM derivatograph. Surprisingly, graphite completely prohibits the expected reduciton of MoO 3 and partially inhibits that of Co 3O 4. The former catalytically lowers the onset combustion temperature of graphite by about 90 ° C and the latter by about 190 ° C. Although both oxides significantly enhance the oxidation of graphite, Co 3O 4 leads to complete conversion of graphite into gaseous products of carbon and therefore is an ideal p-type semiconductive catalyst. X-ray diffraction and evolved gas analysis were employed to identify the intermediate and final products.

Mössbauer, X-ray and derivatographic studies on Egyptian Nile clay

The constituents of the clay minerals in eighteen Nile clay and two Desert (calcareous) samples, were investigated. The physicochemical transformations induced in the iron containing phases were followed by heat treatment. A conclusion was reached about the behaviour of the ferrous and ferric ions at various temperatures. This behabviour is applied to characterize the archaeological Ancient Egyptian pottery.