Айталина Охлопкова

Prof. Айталина Охлопкова

Регистрация в SciProfiles

Research Focus & Metrics

Academic Career Length

26Years (2001-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 January 2019 in Molecules
Verified
Journal Article
Open access
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AVAndrey Petrovich Vasilev
Andrey Petrovich Vasilev
TSTatyana S. Struchkova
Tatyana S. Struchkova
LNLeonid Nikiforov
Leonid Nikiforov
АОАйталина Охлопкова
Айталина Охлопкова
PGPetr Grakovich
Petr Grakovich
JCJin-Ho Cho
Jin-Ho Cho
Mixtures of layered silicates (vermiculite and kaolinite) and carbon fibers were investigated as filler materials for polytetrafluoroethylene. The supramolecular structure and the tribological and mechanical properties of the resulting polymer composite materials were evaluated. The yield strength and compressive strength of the polymer increased by 55% and 60%, respectively, when a mixed filler was used, which was attributed to supramolecular reinforcement of the composites. In addition, the wear resistance increased by 850 times when using vermiculite/kaolinite fillers, which was due to protection of the surface by the formation of hard tribofilms.

7 January 2023 in Polymers
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Journal Article
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AVAndrey Petrovich Vasilev
Andrey Petrovich Vasilev
NLNadezhda N. Lazareva
Nadezhda N. Lazareva
TSTatyana S. Struchkova
Tatyana S. Struchkova
АОАйталина Охлопкова
Айталина Охлопкова
Sakhayana Nikolaevna DanilovaSakhayana Nikolaevna Danilova
Sakhayana Nikolaevna Danilova
The introduction of combined fillers can effectively improve the mechanical and tribological properties of polytetrafluoroethylene (PTFE). In this work, three different types of nanosized fillers (zirconium dioxide, silicon dioxide, and boron nitride) were introduced in a carbon fiber-reinforced polymer matrix for the development of polymer composite materials (PCM). Tensile and compressive testing were carried out, and the hardness of created PCM was evaluated. It is shown that the compressive strength of PCM increased by 30–70%, and the hardness, increased by 38–55% compared to the initial PTFE. The tribological properties of the developed PCM were evaluated under dry friction conditions. An analysis of the results of an experimental study of wear confirmed that the inclusion of combined fillers (two- and three-component) in PTFE significantly increased wear resistance compared to the polymer matrix with a slight increase in the coefficient of friction. It has been shown that the introduction of three-component fillers has an antagonistic effect on the wear resistance of PCMs compared to two-component fillers. The thermodynamic properties of the composites were analyzed by differential scanning calorimetry and a thermomechanical analyzer. The surface morphology of polymer composites after wear testing was studied by IR spectroscopy and scanning electron microscopy to investigate and suggest a possible mechanism for increasing the wear resistance of the developed composites.

1 November 2022 in Polymers
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Journal Article
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IKIuliia Kapitonova
Iuliia Kapitonova
NLNadezhda N. Lazareva
Nadezhda N. Lazareva
PTPraskovia Tarasova
Praskovia Tarasova
АОАйталина Охлопкова
Айталина Охлопкова
SLSamuel Laukkanen
Samuel Laukkanen
VMVasiliy Mukhin
Vasiliy Mukhin
In the present study, the tribological behavior of polytetrafluoroethylene (PTFE) composites filled with natural layered silicates (LS) was investigated. The change in the morphology of the friction surface of composites depending on the content and chemical composition of layered silicates has been shown. The friction surface of PTFE composites with layered silicates was investigated by scanning electron microscopy (SEM). The formation on the friction surface of a special layer with a structure different from the bulk of the polymer, which is formed from particles of fillers and wear products, has been established. The thickness of this layer is independent of the content of layered silicates in the polymer. It was indicated that wear debris of PTFE composites was assembled during friction and uniformly cover the friction surface layer by layer, thereby forming a protective layer.

20 December 2014 in Bulletin of the Korean Chemical Society
Verified
Journal Article
Closed access
IKIu.V. Kirillina
Iu.V. Kirillina
LNLeonid Nikiforov
Leonid Nikiforov
АОАйталина Охлопкова
Айталина Охлопкова
SSS.A. Sleptsova
S.A. Sleptsova
CYCheonho Yoon
Cheonho Yoon
JCJin-Ho Cho
Jin-Ho Cho

28 December 2021 in Lubricants
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Journal Article
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TSTatyana S. Struchkova
Tatyana S. Struchkova
AVAndrey Petrovich Vasilev
Andrey Petrovich Vasilev
АОАйталина Охлопкова
Айталина Охлопкова
Sakhayana Nikolaevna DanilovaSakhayana Nikolaevna Danilova
Sakhayana Nikolaevna Danilova
AAAleksey G. Alekseev
Aleksey G. Alekseev
Currently, lightweight and high-strength polymer composites can provide weight savings in the automotive and process equipment industries by replacing metal parts. Polytetrafluoroethylene and polymer composites based on it are used in various tribological applications due to their excellent antifriction properties and thermal stability. This article examines the effect of combined fillers (carbon fibers and zeolite) on the mechanical, tribological properties, and structure of polytetrafluoroethylene. It is shown that the introduction of combined fillers into polytetrafluoroethylene retains the tensile strength and elongation at break at a content of 1–5 wt.% of carbon fibers, the compressive stress increased by 53%, and the yield stress increased by 45% relative to the initial polymer. The wear resistance of polymer composites increased 810-fold compared to the initial polytetrafluoroethylene while maintaining a low coefficient of friction. The structural features of polymer composites are characterized by X-ray diffraction analysis, infrared spectroscopy, and scanning electron microscopy.

4 February 2021 in Molecules
Verified
Journal Article
Open access
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EKEgor A. Kapitonov
Egor A. Kapitonov
PNPetrova Natalia
Petrova Natalia
VMVasilii V. Mukhin
Vasilii V. Mukhin
LNLeonid A. Nikiforov
Leonid A. Nikiforov
VGVladimir Gogolev
Vladimir Gogolev
JCJin-ho Cho
Jin-ho Cho
The physical and mechanical properties of nitrile–butadiene rubber (NBR) composites with N-cetylpyridinium bromide-carbon black (CPB-CB) were investigated. Addition of 5 parts per hundred rubber (phr) of CPB-CB into NBR improved the tensile strength by 124%, vulcanization rate by 41%, shore hardness by 15%, and decreased the volumetric wear by 7% compared to those of the base rubber-CB composite.