Vestnik of Vitebsk State Technological University

9-17

Authors: Yulia I. Maruschak, Natallia N. Yasinskaya

Exposure to washing and other external factors induces aging in textile materials, adversely affecting their physical and mechanical properties and consequently reducing their lifespan. The study reflects the results of investigation into the impact of repeated washing on the physical and mechanical properties of eco-leather with a polyurethane coating. The samples underwent 5, 10 and 15 wash cycles in a drum-type washing machine using the “Bonus” detergent for delicate fabrics, produced by the Belarusian manufacturer “BZPI”, for 30 minutes at a temperature of 40 °C. Following each wash, the samples were rinsed for 5 minutes, hand-wrung without twisting, and dried. Upon completion of each washing and drying cycle, the elemental samples were stored in standard climatic conditions in a straightened form. The research findings confirmed that the coloring of Belarusian ecoleather is resistant to washing. During the washing process, the material is affected by a combination of physical, mechanical and chemical factors, resulting in the compaction of the structure of the woven base due to fiber swelling. This entails shrinkage of the material and, consequently, a gradual decrease in air permeability and abrasion. The dependence of the breathability of eco-leather on the number of washes is described with a high degree of approximation reliability by a logarithmic law. The influence of washing on the alteration in the linear dimensions of the materials under study is minimal – shrinkage does not exceed 1 %. All studied eco-leather samples exhibited the greatest shrinkage in the direction of the base, ranging from 0.6 to 5.2 %. Based on the research outcomes, recommendations were formulated for the washing regime of eco-leather with a polyurethane coating. It is advised to wash in drum-type washing machines at a temperature of 40 °C for 30–60 minutes. It is recommended to use the “Bonus” product, produced by “BZPI” Company, as a detergent. Handsqueezing without twisting, followed by drying on a flat surface away from direct sunlight, is also recommended.

28-36

Authors: Anton V. Kotovich, Valery I. Alshanski

Currently, flax shive has a small number of applications. It primarily serves as fuel in the furniture industry and construction, with its volumes in enterprises measured in tons. The purpose of the study is to determine the fundamental thermal and physical properties of a silicone-based composite material reinforced with flax shive. The article delineates the thermal and physical properties of a composite material derived from silicone reinforced with flax shive. The material was fabricated through pressing. Samples of the material underwent thermal conductivity testing via the plate method. Based on the test results of the thermal conductivity coefficient of the composite material, a graph illustrating the dependence of the composite’s thermal conductivity on the mass of the constituent materials was constructed. A regression analysis was performed, statistically significant factors were identified and the regression equation of the material’s thermal conductivity coefficient was derived. The logarithmic dependence of the thermal conductivity coefficient of platinum-based silicone, possessing a Shore A hardness of 10, on the thickness was determined. Based on the calculation results, the density of the composite material samples was ascertained, and the regression equation of the sample density from the masses of the components incorporated in the composite material was derived. The thermal resistance, specific heat capacity and thermal conductivity coefficient of each group of samples were calculated. The study outcomes facilitate the calculation of the thermal and physical properties of a composite material with a varying component ratios. The study revealed that the material exhibits heat-insulating properties.

44-50

Authors: Johnson Ezenwankwo, Iva Petrikova, Josef Zak

Fabrics play a key role when used as both reinforced material for composites and simply as apparels. In textile industry, fabric geometrics and weave pattern play a key role in the overall behaviour, mechanical response and general feel and texture of a piece of fabric. The engineering constants of are highly important parameters since the materials are largely orthotropic in nature. It is therefore, pertinent to investigate the effect of some key parameters on the engineering constants of a material, especially when they are used for HSE critical purposes such as reinforced composites employed in the design of aircraft wings, fuselages and other parts. The effect of shear angle on the six engineering constants is investigated using Ansys Material Modeler. Material properties are shown in Table 2 and gotten from measurement from the lab. The model was automatically achieved by inputting the textile geometrics, and generating the RVE, applying the boundary conditions, periodicity of the model and running the simulation. The material properties are given in Table 1, and are deduced from experimental data. To further expound the work, the effect of geometric properties such as fabric thickness, yarn width and yarn spacing will be explored in subsequent work.

61-68

Authors: Alena L. Antonava, Valiantsina E. Sytsko, Victor M. Shapovalov

This article provides information about additives that are used to reduce the flammability of polymer compositions, in particular, flame retardants. At a certain degree of concentration of flame retardants in the material, the fire stops burning, due to various physical and chemical processes that occur, which do not allow the flame to ignite. The characteristics of the flame retardants used by the authors in their scientific research are given. These flame retardants are the following: aluminum hydroxide, magnesium hydroxide, melamine, zinc borate, ammonium polyphosphate. It has been studied that phosphorus-containing compounds have a plasticizing ability, and are also able to increase the fire resistance of plastics. Under the influence of high temperatures, metal hydroxides decompose. The formation of water dilutes the flammable gases that are released during decomposition, reducing the rate of combustion. The effectiveness of hydroxides depends on their content in the polymer. Magnesium hydroxide is more expensive than aluminum hydroxide, but has a higher heat resistance. Flame retardants are key components in reducing the destructive effects of fire. The addition of flame retardants to plastics increases the fire protection parameters of materials, as well as general safety and stability parameters. The use of flame retardants is important because modern homes, with an increasing number of electronic products, pose a higher risk of fire. Therefore, flame retardants provide protection against the destructive effects of fire of various materials. In turn, flame retardants are capable of providing a high degree of fire protection.

84-91

Authors: Mohammad Toufiqul Hoque, Kristina Klinkhammer, Boris Mahltig

With the increased stress in people’s daily lives, the secretion of sweat from the human body has steadily increased. Therefore, textile industries continue to introduce various products to meet consumers’ demands. Thus far, people use more cotton and polyester fabrics among other textile fabrics in their daily usage or total living period. Textile products, especially those made from cellulose fibers such as cotton, can promote the growth of microorganisms due to their high surface area and moisture retention. In contrast to cellulosic materials, polyester contains no chemically functional or hydrophilic groups. Therefore, it is necessary to ensure wearers’ protection as both cotton and polyester can create unwanted odors due to the decomposition of sweat by microorganisms. The application of chitosan on textile substrates is a useful approach for textile functionalization. Chitosan has been reported as a popular finishing agent due to its intrinsic properties, such as biocompatibility, biodegradability, non-toxicity, abundance in nature, antimicrobial, and antistatic ability, etc. In this study, the solution of chitosan was applied to 100 % cotton and polyester fabrics using a common pad-dry-cure technique. The resulting fabrics were characterized by drop-test, scanning electron microscopy (SEM), and color measurement. Thus, this study presents a small overview of the finishing using chitosan-containing recipes on both cotton and polyester fabrics.

102-109

Authors: Salih Ballyev, Farida R. Sagitova, Farid S. Sharifullin

Enhancing the adhesive properties of polyacrylonitrile (PAN) fibers is a significant research and development topic in materials and technology. The adhesive properties of PAN fibers, namely, their ability to adhere to other materials or matrices, play a key role in the production of various composite materials, fiber composites, and carbon fiber products. Enhancement of the adhesive properties of PAN fibers can pose the following challenges: PAN fibers are chemically inert and difficult to form adhesive bonds with other materials. This makes it difficult to glue, stitch, or join with other materials. PAN fibers contain a limited number of active functional groups that can participate in chemical reactions with other materials, thereby reducing adhesion. PAN fibers have a smooth and non-porous surface, which also complicates adherence to other surfaces. The low surface energy of PAN implies that the molecules do not have a high affinity for other materials. In this context, the article addresses the pressing issue of enhancing the adhesive properties of PAN fibers through the use of low-pressure radiofrequency capacitive (RFC) plasma, which facilitates the creation of additional active groups on their surface. Active groups on the surface of the fibers can interact with other materials, such as resins, adhesives, or coatings, enhancing adhesion and creating more reliable connections. The article presents the results of a study of the influence of low-pressure high-frequency capacitive plasma on the adhesive properties of PAN fibers. The results of the adhesive strength and capillarity of PAN fibers after pre-treatment with low pressure plasma are discussed.

124-132

Authors: Nina I. Bohdan

The relevance of the problem of technological sovereignty of countries is due to the fact that access to new technologies can be crucial for their economic sovereignty, which has prompted them to compete fiercely for the development of their technological capabilities. The task of ensuring technological sovereignty has become relevant in the sphere of Russian and Belarusian priorities over the past few years. Following the COVID-19 crisis, disruption of supply chains and increased competition between the US and China, issues of technological sovereignty have become very relevant for developed countries. The article examines the modern discourse on technological sovereignty in the context of sanctions imposed by Western countries against Russia and Belarus. The objective of the study is to determine the concept of technological sovereignty, its connection with the concept of economic sovereignty of the state, and to identify new directions for scientific, technological and innovation policy in the context of changing international relations. The concept of technological sovereignty is considered in connection with the concept of “strategic autonomy”. It is indicated that political changes in recent years have revealed three main types of political intervention to strengthen technological sovereignty and strategic autonomy: protection, promotion, and projection. The challenge for government agencies is to strike an appropriate balance between these types of policy interventions in the context of their own interests and capabilities. An innovation policy that views technological sovereignty as a means rather than an end requires governments to carefully assess which technologies are truly critical and what threats to their access exist. For Belarus, cooperation with Russia within the Union State in the formation of a single scientific and technological space, the growth of the R&D intensity GDP, and new approaches to the formation of macro-indicators of State programs for innovative development are of particular importance.

145-168

Authors: Vera Komarova, Svetlana Ignatyeva, Janis Kudins, Edmunds Cizo

The aim of this research is the identification of comparative priorities of budget expenditures of Latvian municipalities (either on transport infrastructure or production) in the context of improving the local economy. The scientific and practical significance of this study lies in the empirical evidence of current trends indicating the ‘transport-production’ economic restructuring of the territory of Latvia: strengthening economic (and demographic – in terms of population outflow) isolation of the south-eastern part of Latvia, the Latgale region, from the rest of its territory; the emergence of a compact block of ‘production’ self-governments (with a preference for supporting production to the development of transport infrastructure) with a stable population; expansion of the cluster located in the center of Latvia (in and around the metropolitan agglomeration) and consisting of the most economically active ‘transport’ self-governments with a growing population. Methods of the empirical analysis. The authors applied various methods of statistical analysis: frequency analysis, tests for normality and comparison of proportions of paired samples (to study the distribution of various states of the economy of Latvian municipalities), comparison of proportions of independent samples (to determine the statistical significance of differences in the comparative priority of budget expenditures in different groups of Latvian municipalities), correlation analysis (to study the interdependence of ‘transport’ / ‘production’ expenses of Latvian municipalities and the state of the economy of the corresponding territories), cluster analysis (to identify different typological groups of Latvian municipalities according to the studied parameters). Source of empirical information. The authors used empirical data from the Basic Budget Implementation Reports submitted by Latvian municipalities to the State Treasury in 2021 and 2022, taking into account the number of residents in the corresponding municipal territories (to calculate per capita indicators). The results of the empirical analysis show that the comparative priority in the budget expenditures of Latvian municipalities is determined not by the state of the local economy, but rather by the geographical (or geopolitical / geoeconomic) location of the municipal territory. As a result of this, Latvian municipalities are grouped into territorial clusters, reaping the benefits of the agglomeration effect stemming from the concentration of either transport infrastructure or production, with the latter being more pronounced in 2022.