scholarly journals Polyamide self-lubricating composites filled with thermolysis products of lignin: composition, structure, properties

2021 ◽  
Vol 2131 (4) ◽  
pp. 042020
Author(s):  
M Serbinovskiy ◽  
O Popova ◽  
T Finochenko ◽  
A Serbinovskaya
Keyword(s):  
Water Absorption ◽  
Friction Factor ◽  
Carbon Materials ◽  
Microstructural Analysis ◽  
Expanded Graphite ◽  
Thermally Expanded Graphite ◽  
Carbon Additives ◽  
Hydrolytic Lignin ◽  
Composition Structure ◽  
Antifriction Composites

Abstract Compositions of antifriction composites with a polyamide matrix filled with carbon additives obtained by modifying hydrolytic lignin (graphite from lignin, graphite bisulfate from lignin, thermally expanded graphite from lignin) have been developed. Powders of carbon materials were impregnated with cylinder oil before being added to the polyamide matrix. The tribotechnical characteristics of filled polyamide composites, their microstructure and water absorption kinetics have been investigated. It was found that the lowest values of the friction factor are observed in composites filled with thermally expanded graphite from lignin. The friction factor for such composites is 1.5-2 times less than the indicators obtained for currently used graphites. Thus, at specific loads of 0.67 and 2.33 MPa, the friction factor was 0.065 and 0.064, respectively. The investigated antifriction composites have low water absorption compared to pure polyamide. The maximum water absorption (2.2%) in the series of the studied composites had the samples filled with graphite from lignin with an oil content of 9%. According to the data of microstructural analysis, the structure of composites with additives of carbon materials from lignin is homogeneous. The components, including the oil plasticizer, are evenly distributed, the bulk of the oil is localized in the interlayer spaces. The elemental composition of the composites indicates the high chemical purity of the composites. Antifriction composites with the proposed additives are recommended for use in friction units operating in an aqueous mediumor an environment with high humidity.

scholarly journals Carbon nanomaterials for supercapacitors: two electrode scheme

2021 ◽  
Vol 340 ◽  
pp. 01035
Author(s):  
Maxim V. Popov ◽  
Alexander G. Bannov ◽  
Stepan I. Yusin
Keyword(s):  
Activated Carbon ◽  
Carbon Nanofibers ◽  
Carbon Nanomaterials ◽  
Electrode Materials ◽  
Carbon Materials ◽  
Expanded Graphite ◽  
Thermally Expanded Graphite ◽  
Rice Hulls ◽  
Texture Characteristics ◽  
Electrodes For Supercapacitors

In this paper, the electrochemical and texture characteristics of electrode materials made of a number of promising carbon materials for supercapacitors were considered. Carbon nanofibers, thermally expanded graphite, and activated carbon derived from rice hulls were used as electrodes for supercapacitors. The paper presents a technique of synthesis of these electrode materials. A comparison of the capacitive characteristics of the electrodes using two-electrode scheme was carried out.

Morphology and structure characteristics of nanoscale carbon materials containing graphene

2021 ◽  
Vol 6 (4) ◽  
pp. 247-255
Author(s):  
Evgeny K. Belonogov ◽  
Sergey B. Kushev ◽  
Sergey A. Soldatenko ◽  
Tatiana L. Turaeva
Keyword(s):  
Electron Microscopy ◽  
Carbon Materials ◽  
Expanded Graphite ◽  
High Energy ◽  
Mutual Orientation ◽  
Graphene Sheets ◽  
Multilayer Graphene ◽  
Thermally Expanded Graphite ◽  
Graphite Phase ◽  
X Ray

A comprehensive study of the nanostructured powders (graphite GSM-2; Taunit-M; thermally expanded graphite (TEG)) by methods of transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffractometry (XRD), reflection high-energy electron diffraction (RHEED), Raman spectroscopy, was carried out. The experimental XRD halo was interpreted by superimposing theoretical diffraction maxima, and an X-ray amorphous graphite phase was revealed. It was found that the X-ray amorphous phase is characterized by the limiting degree of graphite nanostructuring. From the width of the diffraction rings, the maximum sizes of graphite nanocrystals were estimated, which do not exceed 5 and 10 nm in the [0001] and [ ] directions, respectively. Carbon nanotubes and plates of turbostratic graphene were revealed. The structural and morphological parameters of the nanostructured material “Taunit-M” have been established – multi-walled nanotubes with a diameter of up to 10 nm are combined through an interlayer of X-ray amorphous carbon into flat ribbons up to 40 nm wide. Dark-field TEM images (in reflections of ) revealed moiré patterns that appear on overlapping graphene sheets due to double diffraction of the electron beam. It was found that in thermally expanded graphite, the rotation of graphene sheets ranges from 3 to 4°. Within the graphene sheets, complete dislocations with the Burgers vector b = 1/2 were revealed [1010]. The Fourier analysis of moiré images made it possible to determine the mutual orientation of graphene sheets, to reveal regions of multilayer graphene, and to identify turbostratic graphene. It is shown that the combination of RHEED, TEM, and Fourier transformations of periodic contrast of electron microscopic images is a promising approach to the analysis of the substructure and morphology of nanoscale carbon materials containing graphene and other allotropic modifications of carbon.

scholarly journals The effect of carbon additives on crystal structure of coal tar pitch

2020 ◽  
Vol 64 (10) ◽  
pp. 98-103
Author(s):  
Anna N. Popova ◽  
Keyword(s):  
Carbon Material ◽  
Structural Characteristics ◽  
Thermal Transformation ◽  
Coal Tar ◽  
Expanded Graphite ◽  
Coal Tar Pitch ◽  
Thermally Expanded Graphite ◽  
X Ray ◽  
Carbon Additives ◽  
Structural Methods

The work is devoted to the study of changes in the basic structural characteristics of coal tar pitch during carbonization with various carbon additives that have different textural characteristics. An industrial medium-temperature coal tar pitch with a softening temperature of 87 °C was taken as a starting material, nanosized carbon material "Kemerit", nanotubes, activated carbon, and thermally expanded graphite are considered as carbon additives. It was found in the work that the entire range of considered carbon additives significantly increases the yield of coke residue, while it was noted that a decrease in the amount of released volatile products during the destruction of pitch during its thermal transformation was observed, which is very important for carcinogenic compounds. Of the selected series of carbon additives, the maximum amount of solid residue is formed when nanostructured carbon additives (nanotubes and nanosized carbon material "Kemerit") are introduced into coal tar pitch. The structural characteristics of coal tar pitch before and after the carbonization process, as well as all carbon additives considered in the work, were investigated by the complex of X-ray diffraction methods (X-ray phase and X-ray structural methods of analysis). It was revealed that the formed carbon material, when nanotubes and Kemerite are added to coal tar pitch, is characterized by a more disordered structure when compared with the structure of individual coal tar pitch. The addition of thermally expanded graphite into coal tar pitch promotes the formation of graphite-like structures during pitch carbonization and reduces the amount of volatile carcinogenic compounds during thermal destruction to a greater extent when compared with amorphous carbon additives.

Acoustic density testing of blanks made of thermally expanded graphite

2020 ◽  
Author(s):  
O. P. Bogdan ◽  
O. V. Muravieva ◽  
D. V. Zlobin
Keyword(s):  
Expanded Graphite ◽  
Thermally Expanded Graphite

Adsorption Properties of Natural Carbonaceous Adsorbents and Thermally Expanded Graphite

2003 ◽  
Vol 76 (10) ◽  
pp. 1577-1582 ◽  
Author(s):  
Yu. I. Tarasevich ◽  
S. V. Bondarenko ◽  
V. V. Brutko ◽  
A. I. Zhukova ◽  
G. N. Malysh ◽  
...  
Keyword(s):  
Expanded Graphite ◽  
Adsorption Properties ◽  
Thermally Expanded Graphite ◽  
Carbonaceous Adsorbents

Microstructural Analysis of Petroleum Waste Containing Ceramic Tile

2008 ◽  
Vol 591-593 ◽  
pp. 845-848 ◽  
Author(s):  
Bruno C.A. Pinheiro ◽  
J.N.F. Holanda
Keyword(s):  
Water Absorption ◽  
Microstructural Evolution ◽  
Ceramic Tile ◽  
Sintered Density ◽  
Raw Materials ◽  
Microstructural Analysis ◽  
Linear Shrinkage ◽  
Ceramic Tiles ◽  
Petroleum Waste ◽  
Materials Used

In this work is done a study on the sintered microstructure of ceramic tile paste incorporated with petroleum waste. The raw materials used were kaolin, sodic feldspar, quartz and petroleum waste. The ceramic tiles containing up to 5 wt% petroleum waste were prepared by uniaxial pressing and sintered at 1200°C. The microstructural evolution was examined by SEM. In addition, water absorption, linear shrinkage, and sintered density were determined. The results showed that the microstructure of the ceramic tiles is influenced by the added petroleum waste.

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