The purpose of the present work is to develop methods for assessing the quality of aqueous suspensions of fewlayered graphenes using Raman spectroscopy technique. Aqueous suspensions of few-layered graphene particles were manufactured by direct exfoliation of natural graphite under with ultrasound in the presence of surfactants. An experimental assessment of the effectiveness of different methods of Raman spectroscopy data analysis in order to determine the average number of graphene layers and the defectiveness of few-layered graphene particles was carried out. It is concluded that it is possible to determine the average number of graphene layers in aqueous suspensions of few-layer graphene particles based on the ratio of integral intensities and the position of the G and 2D peaks. Additionally, it is proposed to use the ratio of the peaks of the integrated intensities of peaks D and G as a parameter characterizing the defectiveness of particles of few-layered graphenes. Examples are given of using this approach to assess the quality of graphene samples obtained using various technologies via averaged distribution functions of the number of layers in particles and the ID/IG ratio. It was shown that samples with minimal amount of layers had minimal particle size and high defectivity, while samples with higher number of layers had larger particle size with low defectivity.

The article considers the possibility of using nanotechnology in the production of concrete. Special attention is paid to the method of administration of nano-sized additives, due to their low concentration in the composition of concrete, as well as their tendency to form aggregates. Experimental data on the selection of a type of plasticizing additive to obtain optimum plastic properties of a concrete mix are presented. Thus, on the basis of the experimental data, the plasticizer SP-3 was selected, which allowed to reduce the water-cement ratio from 0.48 to 0.36 without losing the plasticity of the mixture. Data on the development of the composition of nanomodified fine-grained concrete by introducing Taunit-M carbon nanotubes in the amount of 0.01–0.001 % by weight of the binder are also presented. Two methods of introducing carbon nanotubes are considered, namely the technology of ultrasonic dispersion and the use of a vortex layer apparatus. The possibility of combining the two technologies to introduce a complex additive into concrete is considered. The greatest increase in strength (up to 26 %) was achieved when nanotubes were introduced into the mix using a linear induction rotator together with the introduction of a plasticizer into the water using an ultrasonic disperser.

Creation of biodegradable polymers is one of the most prospective trends aimed at solving problems of polymer waste accumulation and processing, and the development of effective oxo-additives for polyolefin raw materials. It is considered to be one of the most promising ways to ensure accelerated degradation of polymer waste in natural conditions. The present research work studies the effect of nanostructured iron oxide microspheres produced with ultrasonic aerosols pyrolysis on accelerated atmospheric aging of polyethylene. Two types of microspheres were used to modify polyethylene microspheres consisting of X-ray amorphous Fe2O3 (initial microspheres after synthesis) and microspheres, consisting of crystalline Fe2O3 (heat-treated). Samples of polyethylene modified with microspheres were aged by simulating cyclic climatic effects (temperature, UV, moisture). After the aging of polyethylene modified with microspheres, a higher degree of surface oxidation was discovered using the method of infrared spectroscopy. A strong surface erosion of polyethylene was observed with the addition of microspheres after aging at the same time, untreated polyethylene was preserved almost unchanged. The present study has shown that modification of polyethylene with iron oxide microspheres beyond the end of materials useful life provides its accelerated decomposition under the influence of the main components of atmospheric impact: light, temperature and humidity. At the same time, the complex of mechanical and technological properties of modified polyethylene remained at the acceptable level, which allows using the developed material for the production of packaging, agricultural and landscape films, which will decompose in natural conditions after the end of their lifetime.

Lightweight photovoltaic modules are becoming increasingly popular in many technical applications. This study proposes an approach to the production of a glass-filled prepreg encapsulant for solar cells lamination. Lamination of solar cells strings can result in the creation of a transparent and mechanically strong protective composite material. Prototypes of composite photovoltaic modules with high-efficiency HJT solar cells connected using electroconductive adhesive technology were fabricated. The climatic resistance of the obtained samples was estimated. It was found that composite modules pass successfully thermal cycling, UV exposure and hail tests. Damp heat test has revealed increased degradation. Degradation caused by moisture penetration initiates corrosion processes in the layers of transparent conductive oxide ITO or contact metallization mesh. The use of composite polymer material makes it possible to reduce the weight of photovoltaic modules due to the use of sheet glass in their design while maintaining an acceptable level of their climatic resistance.

The paper presents the results of adsorption studies on the developed activated carbon material (AM), obtained by two activation methods – with one (AM1) and two activators (AM2), respectively, as well as its compacted versions (AMK) using polyvinyl alcohol (PVА), polyvinyl acetate (PVAС) and basalt fiber (BF) as binders, with regard to typical pollutants of aquatic environments – organic dyes and heavy metals. The carbon materials sorption capacity was assessed by the ability to remove dye molecules – “methylene blue” (MB) and “sunset yellow” (SY) using spectrophotometric analysis, as well as by the ability to remove heavy metal salts – lead (Pb2+) using X-ray fluorescence spectrometry. As a result of adsorption kinetic studies, the absorption capacity of the starting material, activated and compacted materials was determined. The sorption capacity for lead for the materials carbonisate and AMK1 was 71 and 65 mg⋅g–1, respectively, the optimal sorption time was 30 minutes; for the materials AM1, AM2, AMK1/PVА, AMK1/PVAС and AMK1/BF 65, 66, 49, 45, 42 mg⋅g–1 accordingly, the optimal sorption time was 15 min. For MB and SY dyes, the parameters were 1000 – 2010 mg⋅g–1, 66 – 972 mg⋅g–1 and 15 min, respectively. To analyze the adsorption mechanisms using kinetic relationships and sorption isotherms, empirical equations of pseudo-first and pseudo-second order, Elovich equation and intraparticle diffusion model were used. The presented results show the possibility of using the developed activated carbon material as an effective sorbent of organic and inorganic pollutants from aqueous solutions.

The increased attention of researchers to electrically conductive polymers, including polyaniline (PANI), is due to the wide possibilities of its use in the production of supercapacitors, energy storage devices, anticorrosive coatings, detectors, sensors, solar cells, antimicrobial materials, sorbents, and coatings that absorb electromagnetic radiation. However, the instability of the PANI properties during operation limits the practical use of the polymer. In this regard, to date, many attempts have been made to stabilize the characteristics and increase the service life of polyaniline. Thus, new composite materials, which combine PANI and one or more other components, including carbon nanomaterials (carbon nanotubes, graphene, graphene oxide, reduced graphene oxide, mesoporous carbon), montmorillonite, metals, chalcogenides, conductive polymers,were developed. The purpose of this study is to summarize the information accumulated to date on electrically conductive polyaniline and its composites with carbon nanomaterials (CNM), as well as to demonstrate their potential and future prospects. The paper describes the structure and properties of the polymer. Chemical and electrochemical approaches to the synthesis of PANI and composites based on it are considered, attention is paid to the influence of synthesis conditions on the structure and properties of the final reaction products. A brief description of the application of polyaniline and its composites with CNM is given.