Mathematical modeling of the properties of thermal insulation materials based on hollow ceramic microspheres and phenylon

In this work, the creation of heat-insulating materials that are still operable at temperatures up to + 400 °C and have increased physical and mechanical characteristics was studied. This aim was achieved by using a heat-resistant polymer binder phenylon (an aromatic polyamide) and hollow ceramic microspheres, that were used as a filler. Phenylon was produced by OJSC «Polimersintez» in Vladimir. Hollow ceramic microspheres are the floating fractions of flue emissions from solid-fuel thermal power plants. Thermal insulation materials were made by mixing hollow ceramic microspheres with a phenylon solution in dimethylacetamide to the state of «wet sand». Then, the obtained substance was molded the solvent residues were removed. Furthermore, the main properties of the obtained materials were also studied. It was established that the thermal insulation material is characterized by high strength characteristics, has significant resistance to impact loads and is operable at temperatures up to 400 °C The developed thermal insulation materials are intended to be used in the construction of objects operating under the conditions of cyclic exposure to high temperatures (for example, power plants) and in the construction of objects operating under the conditions of cyclic exposure to high temperatures (for example, power facilities).

Polymeric Composite Materials of Tribotechnical Purpose with a High Level of Physical, Mechanical and Thermal Properties

Polymeric composites (PC) of tribological applications with a high level of physical, mechanical and thermal properties based on aromatic polyamide and silica gel have been developed. Regularities have been obtained that describe the effect of the filler content in PC on the friction coefficient, temperature on the friction surface and the intensity of linear wear rate of the studied PC-steel friction pair. It was found that the optimal silica gel content in the polymer matrix is 10 wt %. The morphology of the steel surface of friction after friction interaction with PC based on aromatic polyamide and silica gel was studied. The formation of an antifriction film on the steel surface of friction was discovered, which contributes to a decrease in the friction coefficient, temperature on the friction surface, and the linear wear intensity of the studied PC. The influence of the load and sliding speed on the main tribotechnical characteristics of the PC-steel friction pair has been studied. Mathematical laws were derived that describe the influence of the main external factors (load and sliding speed) on the friction coefficient and intensity of linear wear rate of the studied friction pair. Physical, mechanical and thermal investigations of the developed PC were carried out and it was found that the introduction of 10 wt % silica gel contributes to their 5–10 % increase.

Novel magnetic organic–inorganic hybrids based on aromatic polyamides and ZnFe2O4 nanoparticles with biological activity

Magnetic nanoparticles were creatively selected as stable, inexpensive, biodegradable, facile recoverable, and functionalizable supports for a variety of synthetic and natural polymers. Herein, for the first time, aromatic polyamide was synthesized on the magnetic core of zinc iron oxide (ZnFe2O4). Terephthaloyl chloride and derivations of phenylenediamine were employed as monomers in this polymerization process. The toxicity of the synthesized hybrid at the highest concentration (1000 μg/ml) is 13.65% and on the other hand, the cell viability percentage is 86.35%. So, the prepared hybrid is biocompatible and non-toxic to Hu02 cells. Also, it has antibacterial ability against gram-positive and gram-negative bacteria. Because the results show that the minimum inhibitory concentration (MIC) of the synthesized polymer for bacteria such as Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853 is in the range of 500–1000 µg/ml. Moreover, the hemolytic effect of ZnFe2O4 based hybrid was below 9% at the concentration of 1000 μg/ml. Therefore, it is compatible with red blood cells.

Study of the influence of quick-hardened alloy on the properties of metal polymers

The article explores the effect of quick-hardened alloy PR-N65X25S3R3 based on nickel, (chemical composition – Ni64,6Cr25C1,2Si2,7B2,5Mn0,2Fe3,8) on the physical and mechanical properties of metal-containing polymers. Carried out tests and results have shown that the use of quick-hardened alloys, which are characterized by a set of unique properties, is appropriate. The developed metal-containing polymers that contain aromatic polyamide phenylone and 5 - 20 wt.% of self-fluxing amorphous alloys PR-N65X25S3R3 are characterized by 2 times greater abrasive wear resistance and better adhesive strength between the components. Due to the use of quick-hardened alloy it was possible to increase theeffective filler content from 15 wt.% to 20 wt.% that will increase the electromagnetic properties of metal-containing polymers.

Novel Polyelectrolytes Obtained by Direct Alkylation and Ion Replacement of a New Aromatic Polyamide Copolymer Bearing Pyridinyl Pendant Groups

The following work shows, for the first time, the synthesis and characterization of a new family of polyelectrolytes, along with their preliminary assessments in terms of desalin water treatment. These materials fall into the category of aromatic co-polyamides, which are obtained by the direct condensation of monomers 4,4′-oxydianiline (ODA), isophthaloyl chloride, and 3,5-diamino-N-(pyridin-4-ylmethyl)benzamide (PyMDA). Thereby, the charged nature exhibited by these materials was achieved through the quaternization of PyMDA moieties using linear iodoalkanes of different lengths (CnI with n = 1, 2, 4, and 6). After completing the quaternization process, polyelectrolytes were subjected to a one-step anion substitution process, where iodide counterions were replaced by bis(trifluoromethane)sulfonamide entities. For all the obtained materials, solubility tests were carried out, showing that those alkylated with methyl and ethyl chains exhibit high solubility in rutinary aprotic polar solvents, while those containing n-butyl and n-hexyl units resulted in the formation of insoluble gels. Due to the above, the latest were discarded from this study early on. The structural characterization of the initial neutral co-polyamide was carried out by means of infrared spectroscopy (FT-IR), nuclear magnetic resonance (1H, 13C-NMR), and size-exclusion chromatography (SEC), while the structure of methylated and ethylated polyelectrolytes was successfully confirmed through FT-IR, 1H, 13C, and 19F-NMR. Additionally, the thermal behavior of these materials was analyzed in terms of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), showing thermal degradation temperatures above 300 °C and glass transition temperatures (Tg) above 200 °C, resulting in polymers with outstanding thermal properties for water treatment applications. On the other hand, through the solvent-casting method, both neutral and charged polymers were found to be easily prepared into films, exhibiting a remarkably flexibility. The mechanical properties of the films were analyzed using the traction test, from which tensile strength values ranging between 83.5 and 87.9 Mpa, along with Young’s modulus values between 2.4 and 2.5 Gpa were obtained. Moreover, through contact angle measurements and absorption analysis by immersion, polyelectrolytes showed important changes in terms of affinity against polar and polar substances (water, n-heptane, and benzene), exhibiting a higher rejection regarding the neutral polymer. Finally, as a preliminary test against the seepage of saline waters, thin polymer films (from 11.4 to 17.1 µm) were deposited on top of commercial filter discs and tested as filters of saline solutions ([NaCl] = 1000 and 2000 ppm). These tests revealed a decrease of the salt concentration in the obtained filtrates, with retention values ranging between 6.2 and 20.3%, depending on the concentration of the former solution and the polymer used.