Nikita Podlozhnyuk

The effectiveness of carbon nanomaterials in purifying water from organic dyes has been proven over the previous decade. However, the problem of industrial application of carbon nanomaterials has not yet been solved. This is primarily due to the high cost and low productivity of carbon nanomaterials synthesis methods. This article presents the thermodynamic and kinetic data of rhodamine 6G and methylene blue adsorption on few-layer graphene. Few-layer graphene was obtained by self-propagating high-temperature synthesis from cellulose. It is a promising method which is inexpensive and easy to scale. It was found that the studied few-layer graphene has a high adsorption capacity for both dyes, and the obtained values of adsorption capacity are higher than most of the studied carbon materials, such as carbon nanotubes or activated carbon. The most common adsorption models were used to describe the thermodynamics of the process. The kinetics of the process are described by a pseudo-second-order equation, which is quite common in graphene materials. The proposed adsorption mechanism is based on hydrophobic interaction between adsorbent and adsorbate with the formation of H-π and π–π bonds.

This article examines the effect of few-layer graphene (FLG) at different compositions on the strength, wear resistance, and thermal conductivity of epoxy resin. The FLG composition was varied using ammonium nitrate and potassium nitrate as synthesis precursors. The incorporation of FLG enhanced the compressive strength and wear resistance of epoxy resin. Increasing the number of heteroatoms in the FLG structure had little influence on the compressive strength of epoxy resin but improved its wear resistance.

Coatings based on graphene nanostructures represent one of the most promising solutions for protecting metals from corrosion. However, their application remains unprofitable due to the high production costs, which are caused by the imperfections in graphene nanostructures synthesis methods. Therefore, this work utilized few-layer graphene particles synthesized via self-propagating high-temperature synthesis for coating fabrication. The effectiveness of these coatings in protecting metals against corrosion was tested in a salt spray chamber. It was found that the synthesized coatings provide excellent protection for the steel substrate against corrosion, and their effectiveness is significantly higher than that of polymer coatings based on epoxy resin. A hypothesis was proposed to explain the high efficiency of the coatings based on few-layer graphene particles. This is attributed to their low defect density (absence of Stone-Wales defects in their structure) and the presence of multiple layers, which enhances the barrier effect.

Coatings based on graphene nanostructures exhibit high thermal conductivity and are capable of effectively protecting materials from the negative effects of ultraviolet radiation. However, due to the imperfections of the methods for synthesizing graphene nanostructures and coatings based on them, the practical application of such coatings remains unprofitable. This paper presents the results of a study of the thermal conductivity and UV-protective properties of coatings synthesized by chemically crosslinking few-layer graphene particles on ABS plastic substrates. Few-layer graphene particles synthesized under self-propagating high-temperature synthesis conditions were used as the starting material for the coating synthesis. The synthesized coatings were found to have a thermal conductivity of 244 W/(m × K) and are capable of effectively protecting ABS plastic substrates from the negative effects of UV radiation, allowing the products to maintain their required strength characteristics. The high productivity of the method for synthesizing few-layer graphene (up to 10 kg/month at the laboratory production level), as well as the simplicity of the method for synthesizing coatings based on it, allows us to hope for the cost-effectiveness of such coatings.

Modification of polymer matrices with carbon nanomaterials is a common practice for producing strong and wear-resistant composites. However, carbon nanomaterials are still not widely used in industry due to low-throughput synthesis methods. In this work, the strength and thermophysical properties of a composite based on polylactide modified with few-layer graphene were studied. The introduction of few-layer graphene leads to increase the flexural strength, thermal conductivity and wear resistance of polylactide. Few-layer graphene was obtained by self-propagating high-temperature synthesis. This method is easily scalable and allows to obtain few-layer graphene from carbohydrates. The work discusses the properties of synthesized few-layer graphene and the mechanisms of its interaction with polylactide.

This study presents the results of an investigation into the influence of few-layer graphene, produced by self-propagating high-temperature synthesis from various types of biopolymers (glucose, cellulose, and lignin), on the mechanical, thermophysical, and tribological properties of epoxy resin. It was found that the addition of few-layer graphene at concentrations of up to 1 wt.% leads to an increase in compressive strength by up to 40%, flexural strength by up to 15%, and thermal conductivity by up to 40% compared to the original resin. A fivefold increase in the wear resistance of the composites was also observed compared to pure epoxy resin, due to a reduction in the friction coefficient.

The digital light processing method (DIGITAL LIGHT PROCESSING or DLP) is one of the most affordable 3D printing methods, which allows you to obtain high-precision products, which, however, are inferior in their characteristics to products obtained by other 3D printing methods. Due to their high characteristics, graphene nanostructures can solve this problem by acting as effective modifying additives. However, despite all the promise of this approach, the introduction of graphene nanostructures into actual practice has not yet occurred due to their high cost due to the imperfection of the methods of their synthesis. The paper considers the effectiveness of using few-layer graphene synthesized according to the author's method under conditions of self-propagating high-temperature synthesis from cellulose as a modifying additive to improve the complex strength and thermophysical properties of products from photopolymer resins obtained by DLP 3D printing. It was found that adding few-layer graphene makes it possible to increase Brinell hardness up to 1.8 times, bending strength up to 1.5 times, and thermal conductivity up to 2.2 times compared to the original polymer when using no more than two wt. % few-layer graphene.The data obtained indicate the high efficiency of the synthesized few-layer graphene as a modifying additive in creating products from photopolymer resins using the DLP 3D printing method.