The paper presents the results of a comprehensive study of the effect of the structure of carbon fibers and the type of the initial polymer composite on the quality of the reclaimed fiber obtained by low-temperature solvolysis. The characteristics of the initial and reclaimed carbon fibers were analyzed using a wide range of experimental methods, including structural (X-ray diffraction analysis, scanning electron microscopy, Raman spectroscopy) and thermal studies. Solvolysis was carried out in a mixture of H2SO4 (conc.):H2O2 (conc.): H2O in a mass ratio of 2.5:3:1, respectively, at the boiling point of the solution. The recycling time was 1 h with a solution change every 20 min. The results of electron microscopy showed that, regardless of the type of polymer system, there are practically no binder residues on the surface of the fibers. Using thermal analysis, it was shown that the main mass loss of all samples of the reclaimed fiber occurs at temperatures above 600 ° C. Despite the fact that origin fibers with a smooth surface show greater thermal stability than those with a relief structure (mass loss temperature of 5% - 650°C and 620°C, respectively), extracted fibers based on the same brand have lower mass loss values. In order to assess the destructive effect of the solvolysis solution during extraction, the structural changes in the carbon fiber surface were studied by the method of Raman spectroscopy. The degree of graphitization was estimated by the ratio of the peak areas D (defective component) and G (graphite component). A decrease in the degree of graphitization after solvolysis was shown for both types of carbon fibers. The crystallite sizes of carbon fiber samples were determined by X-ray diffraction analysis. The results showed a decrease in the apparent thickness of Lc and the transverse size of the La crystallite for all samples after solvolysis. For citation: Trukhinov D.K., Lebedeva E.A., Ivanova E.V., Istomina T.S., Astaf’eva S.A. Efficiency of carbon fiber extraction by low-temperature solvolysis. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 4. P. 59-66. DOI: 10.6060/ivkkt.20256804.7162.

A method for the preparation of a hybrid material by modifying the surface of carbon fiber with barium hexaferrite particles using ultrasonic treatment was proposed. Scanning electron microscopy, Raman spectroscopy, and X-ray diffraction were used to identify the barium hexaferrite and to reveal the structural specific features, degree of ordering and homogeneity of the carbon fibers modified with barium hexaferrite. A vibrating magnetometer was used to determine the specific magnetic moment of the obtained hybrid, which was found to be equal to ∼2.03 A m2 kg−1.

With the rapid development of wireless communication technologies and the miniaturization trend in the electronics industry, the reduction of electromagnetic interference has become an important issue. To solve this problem, a lot of attention has been focused on polymer composites with combined functional fillers. In this paper, we report a method for creating an acrylonitrile butadiene styrene (ABS) plastic composite with a low amount of conductive carbon and magnetic fillers preparation. Also, we investigate the mechanical, thermophysical, and electrodynamic characteristics of the resulting composites. Increasing the combined filler amount in the ABS composite from 1 to 5 wt % leads to a composite conductivity growth of almost 50 times. It is necessary to underline the temperature decrease of 5 wt % mass loss and, accordingly, the composite heat resistance reduction with an increase in the combined filler from 1 to 5 wt %, while the thermal conductivity remains almost constant. It was established that electrodynamic and physical-mechanical characteristics depend on the agglomeration of fillers. This work is expected to reveal the potential of combining commercially available fillers to construct effective materials with good electromagnetic interference (EMI) protection using mass production methods (extrusion and injection molding).

A simple and affordable in situ synthesis of a carbon fiber@magnetite hybrid for use as a filler in shielding polymer materials is proposed. The presence of magnetic particles on the carbon fiber was confirmed by X-ray diffraction, and the effect of modification on the structural properties of the components and the magnetic properties of the system was analyzed. The analysis of the structural characteristics and the magnetic properties of the components obtained during the synthesis process was carried out. The modification of the surface of the carbon fiber with magnetite made it possible to obtain for the resulting hybrid a magnetic moment value that is three times higher than that of a mechanical mixture of carbon fiber and magnetite with the same composition.

Results of experiments on small-angle scattering of neutrons and X-rays on colloidal suspensions with anisometric barium hexaferrite nanoparticles in an aqueous solvent are reported. It has been shown that the preparation according to a new method produces fairly stable colloids with two types of particles of reproducible morphology and size: large lamellar-shaped particles ( 100 nm) with a thickness of 7 nm and small isometric particles with a size of 6 nm.

Novel approach to boehmite nanoparticles on the surface of carbon fiber (CF) fabrication has been developed. The AlOOH nanoplates were deposited using a seeded hydrothermal procedure at 160 degrees C for 5 h. As a result, a flower like coating was obtained with a predominantly perpendicular orientation to the CF surface. The structure analysis of the composite was performed by EDS, XRD, Raman, and ATR-IR methods. Surface roughness and interaction with ABS plastic were determined by SEM and contact angle equipment. It was shown that the contact angle decreased from 71.7 to 39.4 degrees and the surface energy increased by 3.14 times through two-stage surface modification. Also, introduction of boehmite nanoparticles as a filler changed tensile strength by 1.5 times (from 12.17 MPa to 18.99 MPa) compared to the functionalized CF.

The effect of microwave radiation treatment on the widely used technical acrylonitrile-butadiene-styrene (ABS) polymer widely used for 3D-printing is studied. The chemical structure and tensile strength characteristics of filled (with 3 wt % carbon fiber) and unfilled ABS plastic irradiated with microwave radiation for 300, 600, 900, and 1200 s are evaluated. It is shown that the effective irradiation time for the mechanical improvement of the filled samples is 300 s, while no significant changes in the mechanical characteristics of the initial ABS samples are found.

The effect of functional additives—short carbon fibers and magnetite—on the mechanical properties of ABS plastic has been studied. It has been established that the maximum increase in the mechanical strength of an ABS plastic sample is observed with the introduction of 3 wt

The mechanical properties of the ABS plastic filled with 3 wt

The development of new polymer composites with conductive and magnetic fillers that are compatible with additive manufacturing (AM) is a highly topical issue. In this work, we discussed the effect of short virgin/ reclaimed carbon fibers and magnetite on the electrodynamic properties of acrylonitrile butadiene styrene (ABS) in the X-band frequencies. The choice of selected frequency range is connected with a large number of various radio engineering systems operating with these frequencies, including radar and satellite communication sys-tems. Composites with the addition of short carbon fiber and magnetite exhibit excellent shielding factors ranging from 37.9 to 33.7 dB at frequencies 8-12 GHz. A detailed study of the electrodynamic parameters revealed the attractive properties of reclaimed carbon fiber as a component of shielding materials, especially with the simultaneous addition of magnetite. It should be noted that for this particular composite, the permit-tivity imaginary part increase was up to-23.96 (88 %) at 8 GHz compared to the virgin carbon fiber and magnetite composite.

Self-reinforced polyurethanes based on oligobutadiene diol have been synthesized by one- and twostage (prepolymer) technique. Some regularities of the hard phase (pseudofiller) formation have been studied by SEM. Breaking strength, modulus and relative elongation have been determined. Mechanical properties and pseudofiller particle size have been found to be dependent both on low molecular alcohol content and synthesis technique. Experimental data treatment by simplex method allowed the optimum composition area to be revealed.

Recently, the fabrication of ferrite nanoparticles in controlled varied shape and ferrofluids obtained with their help has become another requirement of interest for researchers. The present article reports the structural features of a new ferrofluid containing large, rod-like CuFe 2 O 4 particles stabilized by a double layer of triple surfactant. Depending on the experimental method used, i.e., neutrons or X-rays, and, accordingly, the properties of the solvent (H 2 O, D 2 O), several peculiarities of the system, such as the morphology and particle dimensions, and the sizes of the surfactant coatings have been obtained.

Исследовано влияние обработки сверхвысокочастотным излучением широко используемого для 3D-печати технического полимера акрилонитрил-бутадиен-стирола (АБС) с целью улучшения его механических свойств. Проведена оценка механических характеристик и химической структуры исходного и наполненного 3 мас.% углеродного волокна образцов АБС-пластика, облученного сверхвысокочастотным излучением в течение 300, 600, 900 и 1200 с. Показано, что эффективное время воздействия сверхвысокочастотного излучения для улучшения механических свойств АБС-пластика, наполненного углеродным волокном, составляет 300 с; существенного изменения механических характеристик ненаполненного акрилонитрил-бутадиена-стирола не обнаружено.

Solvent-induced interactions of nanoparticles in colloidal solutions can substantially affect their physicochemical and transport properties. Predicting these interactions is challenging because the natural causes of the interactions are unclear. Here, we present a comprehensive experimental and theoretical study of the coagulation stability of the surfacted magnetic colloids. The magnetite nanoparticles stabilized by erucic acid were dispersed in 19 different good solvents. The colloidal stability was reduced by the gradual addition of a precipitant. As a precipitant, 19 other liquids were used. We show that coagulation is not associated with either dispersion or magnetic interactions. The coagulation mechanism is due to the osmotic attraction of nanoparticles induced by a specific local distribution of precipitant molecules. The precipitant molecules are repelled from the hydrophobic tails of the surfactant and form a depleted zone inside the surfactant layer leading to the appearance of the osmotic attraction between the nanoparticles and their subsequent coagulation when the critical concentration of the precipitant is reached. The quantitative description of the phenomenon is carried out within the framework of the generalized Asakura-Oosawa model of the attractive depletion forces between two adjacent particles and the Langmuir adsorption model for the equilibrium concentration of precipitant molecules in the surfactant layer of nanoparticles. The calculated precipitant critical concentrations, the coagulation curves of the polydisperse systems, and the variation of the coagulation criterion occurring upon changing the surfactant are in good agreement with the experimental data. The osmotic attraction mechanism is equally suitable for nanoparticles of any nature' plasmonic, semiconductor, or magnetic. This is determined by the surfactant-solvent interactions and is generic for many solvent-mediated systems taken at arbitrary concentrations of precipitant.

This article presents a new approach to suitability assessment of short reclaimed carbon fiber (rCF) for additive technologies via commonly used analytical methods. Acrylonitrile butadiene styrene (ABS) based plastics rein-forced with virgin or recycled CF samples were received, their mechanical properties and morphology of tensile fractured surface were determined by SEM (Scanning Electron Microscopy) and tensile strength test. As long as operating characteristics of CFRP are affected by single fiber strength as well as adhesion (interfacial interaction) between matrix and CF, this research also includes investigation of fiber surface with Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray diffraction (XRD). Correlation between suggested complex parameters of investigated CF and strength of plastics (CFRP) samples was shown. It was also established that contribution of each investigated parameter is additive.

The chemical precipitation was used to obtain carbon fibers (CF) with surface modified by magnetite particles (Fe3O4). Processing was carried out by employing up to three subsequent coating stages of ultrasonic treatments. After each sonication stage, the coating was 17, 33, and 47 wt. % of the total weight of the modified fibers. Raman spectroscopy indicates the presence in the coating of a mixture of iron II and III states. As-decorated fibers were used to fabricate composites with an epoxy resin (ED-20) matrix cured with PEPA. The quantity of the carbon fiber filler was of 1, 3, and 6 wt %. At room temperature, the saturation magnetization of the soft magnetic samples was 0.37, 0.83, and 1.72 emu/g for the indicated compositions. Carbon fiber reinforced polymer materials with extra functions such as magnetic in this case, are expected to be useful in applications from the power and energy industries.

Mechanical and structural characteristics of gamma-irradiated ABS plastic based on a high-molecular-weight technical acrylonitrile–butadiene–styrene polymer have been studied. The structure and mechanical characteristics of the ABS plastic, both pristine and irradiated with gamma-rays in air at doses of 50, 100, 150, and 200 kGy, have been evaluated. It has been shown that the gamma-radiation post-treatment leads to a change in the structure and mechanical characteristics of the material. In the case of irradiation with a dose of 50 kGy, a sharp increase in strength up to 26.5 MPa is observed with respect to the initial sample, the strength of which is 16.5 MPa, while the strain also almost doubles. At a dose of 100 kGy, the stress and strain somewhat decrease, and this trend persists at radiation doses of 150 and 200 kGy. Based on the results of IR spectroscopy, it was assumed that gamma-irradiation leads to a change in the structure of the plastic; an absorption peak is observed at 3400 cm−1, being absent for the unirradiated sample, the intensity of which increases with increasing radiation dose. The results of the study are proposed to be used for radiation-stimulated enhancement of the strength and plasticity of ABS plastics.

Boron powders with Mg were coated with polytrifluorochloroethylene (PCTFE, fluorine content is 52.6 wt%) and perfluoropelargonic acid (PFPA, fluorine content is 69.6 wt%). They were used to fabricate propellants that were burnt in a reaction chamber designed and fabricated in our lab. Combustion products were studied by Raman spectroscopy, powder agglomeration analysis, electron microscopy, and thermal analysis. Results indicate that surface modification of the initial powder by fluorine-containing components decrease the agglomeration of the combustion products and the strongest effect is for PCTFE. Powders microstructural features and thermal stability of the coatings are discussed as being at the origin of different behavior during combustion of the propellants.(c) 2021 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

The structural and morphological properties of powders of commercial amorphous boron grade B modified with acetonitrile, weak nitric acid, and fluorine-containing compounds are studied by the Brunauer, Emmett and Teller (BET), scanning electron microscopy (SEM), and Raman spectroscopy methods. The influence of these properties on the oxidation of powders is analyzed using thermogravimetric analysis (TGA). It is shown that the removal of the surface layer in the form of boron oxide and boric acid leads to a more complete oxidation degree of the powder.

In order to expand the application range of carbon reinforced composite materials in shielding field, this paper aimed to modify the chopped carbon fiber (CF) by magnetite particles with ultrasonic treatment. The modification was carried out in three stages and the increasing amount of the cover was proved by TGA analyze. SEM analyze is showed the most part of CF surface was coated by magnetite particles Fe3O4. Also it was noticed some agglomeration on each stages what is possibly connected with high surface energy of these particles. The chemical compound of the coating corresponds to ferrous oxide (II and III) what is confirmed by Raman spectroscopy.