Carbon-Carbon Composite Materials Based on Low Modulus Fabrics

2022 ◽  
Vol 1049 ◽  
pp. 240-247
Author(s):  
Ivan S. Zherebcov ◽  
Valeriy V. Savin ◽  
Alexander V. Osadchy ◽  
Victoriia A. Chaika ◽  
Vadim Borkovskih

Scientific research and the search for new technologies to increase the level of mechanical and high-temperature properties are ongoing. The article discusses the technology of using carbon materials, pyrolysis and impregnation with phenol-formaldehyde resins. It is shown that the proposed technology makes it possible to achieve a sufficient level of mechanical properties when using low-modulus carbon fabrics after pyrolytic treatment as a prepreg at a temperature treatment no higher than 900 K. Pillowcase and resole phenol-formaldehyde resins were used to impregnate the prepreg. The proposed technology also allows the introduction of alloying additives into the system to improve the properties. An example of the introduction of nitrogen into a composite by adding urotropine to a phenol-formaldehyde resin, which was used to impregnate the composite, is considered.

Author(s):  
D. A. Brazhnik ◽  
G. D. Semchenko ◽  
G. N. Shabanova ◽  
E. E. Starolat ◽  
I. N. Rozhko ◽  
...  

The possibilities of improving the physico-mechanical properties of periclase-carbon materials by modifying the phenol-formaldehyde resin (PFR) with organoinorganic complexes are described. The composition of the modifying additives, the phase composition of the materials after the PFR hardening are given, the influence of modifiers on the formation of the structure of materials is established. It is shown that the introduction of ethyl silicate or hydrolyzed ethyl silicate into liquid PFR during preparation of the charge contributes to the formation of SiC in the phase composition. The conclusion is made about the rationality of the introduction of ethyl silicate in an amount of from 0,66 to 1 wt. % and the prospects of introducing nickel oxalate into a liquid PFR together with ammonium citrate to increase the compressive strength of periclase-carbon materials up to 60 MPa. Ill. 7. Ref. 9.


2021 ◽  
Vol 340 ◽  
pp. 01042
Author(s):  
Yuliya Sinelnikova ◽  
Nikolai Uvarov

Zinc citrate was prepared and its thermal decomposition was investigated by methods of thermogravimetric analysis and differential scanning calorimetry. Products of the thermal decomposition were investigated by X-ray diffraction analysis. The decomposition proceeds at temperatures 50 - 420 °C in three stages and leads to the formation of nanocrystalline ZnO with the average grain size of 23 nm. Subsequently, zinc citrate was used as a precursor of ZnO hard template for preparation of carbon mesoporous materials by the solid template method. The carbon materials were obtained by pyrolysis of polymer matrix of phenol-formaldehyde resin in which zinc citrate was added. It was found that the resulting material has a specific surface area of 1051 m2/g. According to the cyclic voltamperometry data, the material has a specific capacity 40 F/g.


2020 ◽  
pp. 34-43
Author(s):  
N. R. Memetov ◽  
◽  
A. V. Gerasimova ◽  
A. E. Kucherova ◽  
◽  
...  

The paper evaluates the effectiveness of the use of graphene nanostructures in the purification of lead (II) ions to improve the ecological situation of water bodies. The mechanisms and characteristic parameters of the adsorption process were analyzed using empirical models of isotherms at temperatures of 298, 303, 313 and 323 K, which correspond to the following order (based on the correlation coefficient): Langmuir (0.99) > Temkin (0.97) > Dubinin – Radushkevich (0.90). The maximum adsorption capacity of the material corresponds to the range from 230 to 260 mg/g. We research the equilibrium at the level of thermodynamic parameter estimates, which indicates the spontaneity of the process, the endothermic nature and structure change of graphene modified with phenol-formaldehyde resin during the adsorption of lead (II) ions, leading to an increase in the disorder of the system.


Sign in / Sign up

Export Citation Format

Share Document