ДРЕВЕСНОСТЕКЛОВОЛОКНИСТЫЕ КОМПОЗИЦИОННЫЕ МАТЕРИАЛЫ НА ОСНОВЕ ПОЛИЭФИРНЫХ СМОЛ ДЛЯ КОНСТРУКЦИЙ ШПАЛ ЛЕСОВОЗНЫХ ЖЕЛЕЗНЫХ ДОРОГ

CURRENT TRENDS IN THE PRODUCTION AND APPLICATION OF CONSTRUCTION MATERIALS AT THE ENTERPRISES OF THE OIL REFINING AND COKE MAKING INDUSTRY OF UKRAINE © B.K. Artyshchenko, A.B. Grigorov, Doctor of Technical Sciences (National Technical University "Kharkiv Polytechnic Institute", 61002, Kharkiv, Kirpicheva st., 2, Ukraine) The article presents the results of the analysis of current trends in the production and use of structural materials at the enterprises of the oil refining and coke industry of Ukraine. It has been determined that the most promising materials are non-metallic composite materials, products from which have a number of significant advantages (high resistance to aggressive environments, lighter weight, relative simplicity of production, installation and use, and significantly lower cost) compared to metal ones. The article presents classifications of non-metallic structural materials by functional properties. This makes it possible to formulate the basic requirements for the components that make up composite materials. It has been established that enterprises of the oil refining and coke-chemical industries of Ukraine, given the peculiarities of the technological process, need chemical-resistant structural materials (CRSM), which, according to the proposed general formula, consist of a polymer, filler, lubricant, catalyst (if necessary) and dye. Moreover, it is proposed to use secondary raw materials for the production of CSCM – industrial and consumption wastes. This approach serves as the basis for the formation of the circular economy of Ukraine and can significantly reduce production costs and the negative environmental impact on the environment. Based on the formulated requirements for the main components of CFCM and their properties determined by the identified components, a list of materials that can be effectively used in the production of CFCM is proposed. These materials, depending on the component in the CFCM formula, include waste polyethylene products (LDPE and HDPE), polypropylene (PP) and polyethylene terephthalate (PET); sand, natural and waste clays, coke dust, ash and slag, mechanical impurities, construction waste; heavy oil residues, oil sludge and acidic tar; waste lubricating oils and greases, selective oil purification products, substandard oil products. Keywords: composite materials, chemical resistance, oil refining industry, coke-chemical industry, coke dust, oil residues, ash and slag, construction waste, mechanical impurities. Corresponding author A.B. Grigorov, e-mail: grigorovandrey@ukr.net

Physical, thermal, dielectric and chemical properties of a hyperbranched polyether and its linear analog

Due to the high‐power environments of electronic components, achieving the exceptional dielectric properties and mechanical behavior necessary for electronic packaging materials presents a significant challenge. In this study, a trifunctional maleimide (HTMI) was synthesized by reacting hexamethylene diisocyanate trimer (HDI trimer) with Maleic anhydride (MA), followed by the preparation of Bismaleimide (BMI) resin featuring a micro‐branching structure through its reaction with diallyl bisphenol A (DBA) ether and BMI. The intentionally designed micro‐branching structure resulted in an increase in the free volume within BMI, leading to an 8.8% reduction in the dielectric constant. Additionally, this micro‐branching architecture imparted superior mechanical properties to the BMI resin, as demonstrated by a 140% increase in bending strength and a 149% increase in impact strength of the cured product.

This research aims to investigate using sugar palm fiber (SPF) and glass fiber (GF) in an epoxy matrix to develop composite materials with improved mechanical, morphological, and flammability properties. The mechanical and flammability properties are examined per ASTM standards, while the morphological study examines the fractured surfaces of the samples. Using the hand lay-up technique, the hybrid composite comprises 15% SPF, 15% GF, and 70% epoxy resin. Three treatments are applied to the SPF: untreated, alkaline treated, and benzoyl chloride treated, which enables research into the effect of fiber treatment on mechanical properties and flammability. The morphological investigation reveals that both treated SPF/GF/EP composites exhibit lower tensile strength than the untreated SPF/GF/EP composite due to inadequate mechanical interlocking at the fiber-matrix interface. However, the alkaline-treated SPF/GF/EP composite demonstrates a 24.8% improvement in flexural strength, a 1.52% increase in impact strength, and a 9.76% enhancement in flammability. Similarly, the benzoyl chloride-treated SPF/GF/EP composite improves flexural strength, impact strength, and flammability by 24.6%, 0.51%, and 5.66%, respectively. These results highlight the potential of fiber treatment to improve composite materials’ mechanical and flammability properties.

This work reports the exploitation of nanocrystalline Ni0.5Zn0.5Fe2-xCexO4 ferrite for potential application by designing quasi-spherical shaped polythiophene (PTH) composites via in situ emulsion polymerization. The structural, electronic, dielectric, magnetic, and electromagnetic interference (EMI) shielding properties of PTH/Ni0.5Zn0.5Fe2-xCexO4 composites were investigated. Our results suggest that these properties could be optimized by modulating the concentration of x (composition) in the polymer matrix. Higher values of ε' and ε'' were obtained on composite formation, and could be due to the heterogeneity developed in the material. An enhancement in the value of saturation magnetization (123 emu g-1 for x = 0.04) and Curie temperature was obtained with Ce concentration, which is useful for high density recording purposes. A low value of saturation magnetization was obtained for the PTH/Ni0.5Zn0.5Fe2-xCexO4 composite (36 emu g-1 for x = 0.04). This could be attributed to the non-magnetic nature of the polymer. A total shielding effectiveness (SET = SEA + SER) up to 34 dB (≈99.9% attenuation) was recorded for PTH/Ni0.5Zn0.5Fe2-xCexO4 composites (x = 0.04) in a frequency range of 8.2-12.4 GHz (X-band), which surpasses the shielding criteria of SET > 30 dB for commercial purposes. Such a material with high SE identifies its potential for making electromagnetic shields. The effect of Ce substitution on the microstructure, dielectric, impedance and magnetic properties of PTH/Ni0.5Zn0.5Fe2-xCexO4 ferrite composites was also investigated. X-ray diffraction analysis confirmed cubic spinel phase formation, and the broad reflection peaks indicated the formation of smaller sized particles. The smaller energy band gap (2.53 eV) of the composite indicated that this material could be used for photocatalysis in the visible region. Dielectric and impedance measurements were carried out in a frequency range of 8.2-12.4 GHz. Dielectric properties were improved considerably by the substitution of Ce3+ ions in PTH/Ni0.5Zn0.5Fe2-xCexO4 composites. Impedance spectroscopy was used to study the effect of grain and grain boundaries on the electrical properties of PTH/Ni0.5Zn0.5Fe2-xCexO4 composites. Cole-Cole plots showed the formation of single semi-circles for all samples in the measured frequency range. This showed that the composite material was composed of good conducting grains and poorly conducting grain boundaries.

At the moment, there is a wide variety of materials for air filtration, however, it is necessary to develop new, more efficient and cost-effective materials. Numerous studies have shown that in order to obtain a highly effective filter material for fine air purification from particles of 0.1–0.5 μm, ultrafine and microfine glass fibers should be introduced into the composition. Glass fibers have a whole complex of unique properties: thermal, chemical and biological resistance, high specific surface area, filtering ability, strength and resistance to aggressive media. At the same time, glass fibers, unlike fibers of plant origin, do not have the ability to fibrillate, swell and bond formation. Therefore, a strong filter material requires a binder that provides the necessary technological strength while maintaining the specified filtering characteristics. The study of composite material based on mineral fiber was carried out, polyadherical complexes of aluminum, thermomechanical pulp (TMP), polyvinyl acetate (PVA) and polyethylene (PE) were used as binders. The main indicators are the tensile strength, capillary absorption, resistance to air flow and permeability coefficient. The novelty of this work lies in the application of TMP and PE as binders in the composite material based on glass fibers. The addition of a binder based on TMP to the composition is advisable in the range of 5–30 % of the fiber mass, for PE this range is 2–10 %. The studied composite material with the addition of PE as a binder has sufficient technological strength, a low coefficient of permeability and resistance to air flow. PE can be used as a promising binder for composite filter materials based on glass fibers for air purification.

Preparation and properties of the barium borate glassy matrix composite materials containing fused silica and monoclinic zirconia

Composite materials play important roles in multifunctional applications, and thus, the diagnosis of damage patterns in composite materials becomes crucial to avoid critical events such as structural or functional failures. The impact of an individual damage in composite materials has been extensively studied, however, the interaction of defects/cracks, which leads to critical fracture paths, has not been understood well. In this paper, we develop a Bayesian estimation based statistical analysis technique that estimates the damage pattern of a composite material, in particular, the relative positions of defects in the material, by measuring its through-thickness dielectric properties. We first explain the fundamental dielectric principle that leads to the detection of defect patterns. A capacitance model is then built to measure the material permittivity, and the relationship between the dielectric permittivity and relative positions are found using COMSOL Multiphysics. The interaction effects between defects observed in the simulation are interpreted using the fundamental dielectric principle. A Bayesian estimation based statistical analysis model is then developed to estimate the relative positions of defects in composite materials from the measured global dielectric properties.

In the expanding field of high‐performance materials, polymer‐based thermoset composites play an important role due to their favorably‐high strength/weight ratio and their mechanical performance, thermal stability, and chemical resistance. However, their chemically‐crosslinked nature hampers their re‐processability and efficient recyclability, thus making them not compliant with the principles of the circular economy and of end‐of‐life valorization. Dynamic covalent polymers able to modify their network topology upon thermal stimulus can be considered valid alternatives to commonly used thermosets as they offer advantages in terms of recyclability and reusability, normally not achievable with conventional cross‐linked systems. Within the broad field of dynamic polymers, thermally‐triggered Diels‐Alder based materials represent reliable platforms with enormous technological and industrial potential as repairable, reusable and recyclable matrices in composites given their chemical versatility, suitable mechanical performance and ease of production and processing. In this review, a comprehensive discussion of the most recent demonstrations of the reversibility, reprocessability and recyclablability of such systems is provided, in the context of their use as polymer matrices in composites. It is hoped that this work will stimulate further discussion and research in the area of reversible polymer composites with increased functionality and extended lifetime, in view of their application in future circular economy scenarios.

This study has investigated the effect of hydroperoxide treatment on the properties of bagasse fibers in order to get the value added material using by-products from sugar production such as reinforcement for composite materials. The results of processing bagasse fibers with hydroperoxide at different concentration, temperature and treatement time showed that treatment condition had a great influence on the properties of the obtained fibers. With the suitable treatement conditions of 10% peroxide concentration, treatment time of 40 minutes, treatment temperature at 60 0C, the treated fiber has a more homogeneous surface than the untreated. The composite using hybrid bagasse/glass fiber has higher flexural and impact resistance than when using glass fiber and reaches 162.6 MPa and 38.9 KJ/m2 (16.7% and 213% respectively compared to composite using glass fiber only). This can be explained that the treated bagasse fiber has better wetting ability with the matrix resin and together with the energy absorption capacity of the fiber bundle, it leads to an increase in flexural strength and impact strength of composite material.

Thermoplastic composite materials are very advantageous as component layers in subsea risers due to their inherent properties such as high strength, low density, fatigue and chemical resistance. However, response of composite materials to applied loading is complex and three-dimensional in nature. The heterogeneous structure of the composite material induces irregular distribution of stress/strain over the cross-section and thus, it is essential for design to use analytical methods capable of determining the stress-strain relationship in three-dimensional space. Currently, most methods rely upon one-dimensional or two-dimensional data collection techniques with macro scale stress / strain observations for experimental validation. In order to ascertain the correct load to the failure, a complete understanding of the material failure at the micro-scale is essential. In this work, X-ray computed tomography is employed for the in situ observation of micromechanical failure of the composite material under a compressive load. The observed results are compared and validated with the traditional stress-strain data and finite element analysis. It is observed that the damage in the composite material initiates by delamination which grows as the loading progresses. Moreover, the properties and failure modes are highly dependent on the manufacturing process. By gaining further understanding of the failure modes using these methods, the findings can be utilized in optimizing the design of composite riser structures.

In this research work, the effect of individual and hybridized reinforcement of sisal fibrils with randomly distributed short sisal fibers has been investigated. The sisal fibrils (SP) and sisal fibers (SF) were reinforced with phenol formaldehyde matrix using hot stage compression molding technique. Composite laminates were prepared keeping the total wt% of the fibrils/fibers to be 40. The mechanical strength of SP reinforced phenol formaldehyde laminates was found to be superior as compared to sisal fiber and sisal fibril/fiber hybrid reinforced laminates. The 40 wt% sisal fibril reinforced composite laminates (SP40PF60) showed 73% and 25% increase in tensile strength, 78% and 23% increase in flexural strength, and 174% and 44% increase in impact strength as compared to 40 wt% sisal fiber reinforced laminates (SF40PF60) and 40 wt% hybrid reinforced (having equal proportion of fibrils and fibers) laminates (SF20SP20PF60). The dielectric properties of SP40PF60 increased by 14% and 9% as compared to SF40PF60 and SF20SP20PF60 laminates. Thermo‐gravimetric analysis analysis also showed higher thermal stability for sisal fibril phenol formaldehyde laminates than pure fiber and fibril/fiber hybrid laminates. Scanning electron microscopy was carried out to understand the nature of fibril/fiber/matrix interface. These laminates have been specially designed for press boards used in transformer assembly as environment friendly high mechanical strength and electrical insulating material. Additionally, these laminates can be useful for various fields such as electrical and aerospace industry.

Effect of Aging on mechanical behaviour of ADC12-Fly Ash particulate composite.

Polymer concrete (PC) is a composite construction material that boasts several advantages, such as lightness, low water permeability, high resistance to corrosive environments, and chemical degradation. Consequently, it has recently attracted interest as an alternative material to the traditional ones for several civil applications. In this study, unsaturated polyester resin was considered the matrix phase of PC. Aimed to produce green PC, the commonly dispersed phase of natural aggregate was totally replaced by recycled glass aggregate (RGA) deriving from cathode ray tube (CRT) glass waste. Fine and coarse fractions of non-hazardous CRT glass were considered in different ratios. Chemical and physical analyses were carried out through XRF, particle size distribution and microstructural analysis to characterize RGA. The influence of RGA particle size and percentage on PC performance was investigated by microstructural analysis and aggregate packing, chemical resistance, water absorption, and mechanical analyses, such as bending, impact, and scratch test. Using solely the coarse fraction of RGA led to the manufacturing of a green PC with similar performance to the traditional PC and in addition lower in density. The PC quality mainly depended on the matrix crosslinking which, for PC containing fine RGA, was promoted by adding 4 wt% of silane coupling agent.

The aim of the work was to propose the application for waste secondary materials as filler in polymer coating systems. Authors decided to use two different water-based epoxide binders: Lena N141 and Lena N 121 and the waste suitable materials were chosen by its chemical and physical composition and properties. Used recycled materials were glass of windscreen, glass beads, screen, glass packaging and fluorescent glass. The particle size and scanning of grain were determined. The chemical resistance and the adhesion of coating materials to the common substrate were also tested. The chemical resistance was tested with substances: distilled water, oil, petrol, acetone, 20% water solution of NaCl, 50 % water solution of ethanol, 5 % and 30 % water solution of NaOH a 20 % water solution of H2SO4.