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A series of new wholly aromatic (co)polyesters based on m-substituted bifunctional comonomers—4′-hydroxybiphenyl-3-carboxylic (3HBCA) and 3-hydroxybenzoic (3HBA) acids with molar ratios of 3HBCA:3HBA from 0:100 to 60:40, respectively—was synthesized. NMR and FTIR spectroscopy methods proved the full compliance of the copolymer composition with the target ratio of comonomers, as well as high compositional homogeneity (absence of block sequences). The resulting copolyesters have a sufficiently high molecular weight and their intrinsic viscosity values are in the range of 0.6–0.8 dL/g. Thermal analysis showed that all 3HBCA-3HBA copolyesters are amorphous, and with an increase in the content of biphenyl units (3HBCA), the glass transition temperature increases significantly (up to 190 °C). The onset of the intense thermal decomposition of the synthesized polyesters occurs above 450 °C. Thus, this indicates a sufficiently high thermal stability of these polyesters. Rheological measurements have shown that melts of copolyesters with a high content of 3HBCA units exhibit anisotropic properties. At the same time, the method of polarization optical microscopy did not confirm the transition to the liquid crystal state for these polyesters. These results confirm that it is possible to obtain high-performance polyesters based on 3HBCA, but not a mesogenic comonomer. Thus, 3HBCA is a promising comonomer for the synthesis of new thermotropic copolyesters with controlled anisotropic properties.

A series of experiments has been carried out in order to construct a master curve generalizing the combined impact of temperature and low viscosity additives on the viscosity of heavy crude oil. Th...

A series of novel copolyesters based on polyethylene terephthalate (PET) and 4′-hydroxy-biphenyl-4-carboxylic acid (HBCA) was obtained by melt polycondensation of bis(2-hydroxyethyl) terephthalate and 4′-acetoxybiphenyl-4-carboxylic acid (ABCA) as co-monomers with Sb2O3 as a catalyst. Using this synthetic procedure, a set of copolymers containing 20–80 mol% of HBCA units was prepared. According to NMR spectroscopy, the copolymers were of random composition. Copolyesters comprising 60–80 mol% of HBCA possessed increased heat resistance and formed nematic melts at 270 °C and higher. The liquid crystal (LC) phase formation was accompanied by transition to non-Newtonian characteristics of the melt flow, as well as an equalization of storage and loss moduli values. According to XRD and polarizing microscopy, the LC glassy phase of the copolyesters coexists with crystalline regions of poly-(4′-hydroxy-4-biphenylcarboxylate), non-melting up to 400 °C and above. The mechanical characteristics of these LC copolyesters showed similar or better values than those of well-known LC polymers. These novel copolyesters can be useful in obtaining heat-resistant materials with an ordered structure and, as a consequence, improved performance.

A systematic study of the influence of surfactant and stabilizing polymer additives on the rheological properties of heavy oil was carried out. The aim was to optimize the recipe for the most effective reduction in the oil viscosity. A total of 41 versions of the emulsion were prepared using different protocols. Creation of the emulsions with different recipes and modes of mixing led to a regulation of their morphologies, which determined the rheological properties of the final products. In all cases, emulsification resulted in a transformation of the oil from Newtonian behavior to a viscoplastic medium with a blurred yield stress. Dependent upon the composition, the yield stress was decreased up to 0.6 Pa and the viscosity at high shear obtained a value up to 50 mPa s, which is lower than the viscosity of crude oil by 34 times. The efficiency of the viscosity reduction increased with a decreasing temperature.

This review discusses the main aspects of synthesis, structural modification, and practical application of an extremely important class of organic heterocyclic compounds, phthalocyanines and their metal complexes. The main attention is paid to application of phthalocyanines, in such promising areas as tribologically active systems, functional composite materials and coatings, and supramolecular chemistry.

Rheological and morphological properties of heavy crude oil-in-water (O/W) emulsions have been studied. Two series of emulsions were considered: first, the surfactant type remained constant, while the continuous phase content was varied and second, the surfactant type was varied while the continuous phase content remained constant. Under stress-controlled shearing, all samples exhibit viscoplastic behavior. The rheological properties are directly related to the morphology of the emulsions which vary in size of dispersed phase droplets and their inherent structure. Adding a surfactant characterized by a high value of interfacial oil-water tension results in a decrease in the yield stress (which is a measure of the interparticulate structure strength). The same effect is attained by increasing the water content. Meanwhile, these two factors determine the viscosity which can be much lower than that of the basic heavy crude oil if the O/W type of emulsions has been created. Special attention was paid to the viscoelastic properties which have been scarcely reported. Correlations were found between the surfactant properties, composition of the emulsion, and rheological characteristics of emulsions (yield stress, apparent viscosity, and viscoelastic properties), which allows for reduction in the crude oil viscosity down to a low enough level acceptable for pipe transportation.

New antifriction composition coatings based on Ni–P alloy and nanodisperse particles of copper phthalocyanate (CuPc) modified with 4-benzenediazonium carboxylate have been prepared and investigated. The effect of the content of carboxylic groups in the disperse phase on the wear resistance of the coatings has been studied, and the optimal concentration of CuPc in the suspension for the autocatalytic deposition of composition coatings has been determined.

The effect of the nature of the metal in metal phthalocyanites on the electrokinetic potential and рН of the isoelectric point (рН(I)) in suspensions of these substances in NaCl solution (0.1 mol/L) is elucidated. The рН(I) values of unmodified МРс increases in a sequence MnPc < CoPc < СuPc ≈ ZnPc on account of the decreasing effective charge of the coordinated metal ion that corresponds to the Irving–Williams series. The impact of the functional group upon heterogeneous modification of МРс nanoparticles is studied, as well. It is established that the modifying group (the oxygenic properties) exerts a stronger influence on (pH(I)) than the metal nature.

The subject of this study was an aromatic polyamide in dimethylacetamide/LiCl solutions in a concentration range from 0.5 vol. % – 5 vol. %. Dilute and semi-dilute solutions of this polymer demonstrate a complex of unexpected time- and temperature-dependent rheological effects under shearing in a heating–cooling cycle. In a static state, all systems under study are transparent solutions and no temperature-dependent thermal or visual effects are observed. However, superposition of shearing radically changes the situation. Heating up to 100 °C–140 °C leads to the phase separation with the coexistence of the amorphous and LC phases. On cooling of low-concentrated solutions, a decrease in the temperature leads to a several-times increase in the viscosity, and the subsequent viscosity decrease takes place at further temperature decrease. Both changes are kinetic effects. The first one is treated as an order-to-disorder transition. The decrease in viscosity is accompanied by a heat release, which reflects the reverse process of the disorder-to-order state transition. The isothermal viscosity decline in time is described by the Maxwell relaxation law with temperature-independent relaxation time. Hence, this is a non-temperature-activated process. At higher concentrations, strong temperature thixotropic behavior with much lower viscosity values on cooling, in comparison with the heating, is characteristic of these solutions due to their tendency for undercooling. The shear-induced transition, conjugated with the heat excess, was observed in semi-dilute solutions at the same temperature similar to that observed for dilute solutions. So during cooling under shearing, the solutions under study display a rather unusual phenomenon of a first-order transition. This type of phenomenon has not been described before. The phase transitions become quite evident in the polarized light. The observed kinetic effects in transient physical states are discussed on the basis of the concept of delayed and latent structure and phase transitions, including the formation of the LC state, which are initiated by the shearing.