Mukhammedova M., Barnoyev B.
METHODS OF ANALYSIS OF CHROMED LEATHER COMPOSITION AND RECYCLING OF LEATHER WASTE *
Аннотация:
tanneries generate large amounts of waste containing environmentally harmful chemical compounds such as chromium used in the tanning process. Until now, they have been almost entirely thrown into landfills. Thus, the compositional analysis of these wastes and finding environmentally sustainable and innovative alternatives for waste disposal is becoming a major challenge for tanneries and researchers worldwide. This article presents the state-of-the-art strategies related to the processing and evaluation of hydrolyzed collagen and skin waste for the realization of composite materials, as well as information on the properties of the obtained materials and their industrial applications.
Ключевые слова:
composite materials, skin waste, collagen, hydrolysis, disposal, exploitation
The waste disposal process of leather, footwear and leather production enterprises is becoming one of the important socio-economic and technical problems of modern development [1].In particular, industry is using waste to produce new materials that are strongly related to the macromolecular structure of collagen, which is the main component of the skin. In the scientific literature on leather waste management, work is being carried out on the mechanical properties of materials that are fundamental for the use of leather for the preparation of composite materials and the effective industrial exploitation of leather waste. One of the urgent issues is the properties and industrial application of materials derived from strategies related to the recovery and evaluation of hydrolyzed collagen and skin waste for the realization of composite materials.Direct disposal of solidly selected wastes for the preparation of composite materials is common. Fibers obtained from various skin wastes can be combined with granules and other additives or used as reinforcing agents in various polymer matrices after chemical modification. The resulting compositions have properties that depend on the composition of the skin and the compatibility between the polymer matrix and the skin. However, the scientific studies carried out on the effect of adhesion between the matrix and the skin and the conforming effect on the improvement of the composite properties have not yet been fully reviewed. The article is dedicated to solving this research gap.Figure 1. Classification of waste in leather production.Several studies have been conducted on the use of biodegradable polymer matrices (e.g., PHA and PLA). However, it should be taken into account that the polymer remains in the biodegradation of the matrix. The ISO EN 13423 industrial compostability standard specifies a limit of 50 mg chromium per kg of biopolymer. Furthermore, the ultimate presence of Cr(VI) may cause more problems due to its high toxicity. Therefore, the most promising class of biopolymers used in skin composites are polymers derived from renewable resources, which can be efficiently recycled and therefore do not release chromium into the environment[2].One of the main problems to be solved in the near future is related to the measurement of Cr(VI) in composite materials. In fact, all the methods used to determine the amount of Cr (VI) in skin are based on the measurement of chromium (VI) obtained after washing. Because mobility and therefore leaching is strongly reduced within the polymer matrices, this type of testing may lead to results that do not reflect the true content of Cr(VI) within the composite material. In addition, the oxidation of chromium to Cr (VI) is accelerated under the influence of temperature, and most of the polymer / leather composites are obtained by melt mixing methods, which occur at temperatures above 150 ° C and increase the content of Cr (VI) during the composite preparation process. Therefore, it is important to develop an accurate and robust method for the accurate measurement of Cr (VI) content in leather/polymer composites from the point of view of industrial exploitation of these composite materials.Experiments are being carried out in laboratory conditions: the structural condition of leather cardboard was studied, and the initial condition of leather cardboard was obtained by mechanical processing of leather and cardboard waste.Figure 2. Microscopic views of leather-cardboard and cardboard, which are the types of pads used for shoe soles: a) leather-cardboard, b) cardboard.The ability to comprehensively improve the properties of shoe cardboard due to reactive high-frequency plasma treatment is of great interest in shoe cardboard production technology, because traditional methods of changing the properties of this material cause a number of problems, the most important of which are: shortage of raw materials and is environmental pollution [3].Fig. 3. The initial version of leather-cardboard obtained on the basis of scientific research.The main components in the production of this material include chromed leather scraps and cellulose-containing paper materials. A one-layer casting method using skin and cellulose fibers bonded with synthetic or natural polymers in the form of dispersion is used. Leather cartons intended for shoes are classified by their hardness, flexibility, density, thickness and stability.To get a new product by combining these two components, it is passed through mechanical and chemical stages. In the initial mechanical processes, leather and paper scraps are crushed, and various chemicals and biological pests that have an adverse effect on the human body are cleaned by chemical treatment. After chemical treatments, the semi-finished product is exposed to a highly polar solvent, and the particles are glued together and assembled.
Номер журнала Вестник науки №7 (76) том 4
Ссылка для цитирования:
Mukhammedova M., Barnoyev B. METHODS OF ANALYSIS OF CHROMED LEATHER COMPOSITION AND RECYCLING OF LEATHER WASTE // Вестник науки №7 (76) том 4. С. 373 - 377. 2024 г. ISSN 2712-8849 // Электронный ресурс: https://www.вестник-науки.рф/article/16948 (дата обращения: 22.01.2025 г.)
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