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Hygroscopicity, moisture return, wetting, capillarity and water vapour permeability of materials were studied in shoes linings and insoles made of natural and artificial leather. It was established that liquid-based and final finishing deteriorate hygienic properties of natural leather to a great extend. With the use of obtained results, a new graphically-numerical method was tested in assessment of shoe material comfortability, the materials that have direct contact with the human foot. According to the method, the ratio between pentagon areas of material tested and reference material is taken as quantitative indicator of quality.

The structural and phase transition and thermal stability of preparations in the form of hide powder and gelatin, obtained by several ways from untanned-collagen-containing materials of leather industry, have been investigated by differential, thermal and thermogravimetric analysis. In the conditions of temperature programmable change, the character of the thermal process has been ascertained, its thermal characteristics have been determined, and the presence of several stages of thermooxidative destruction has been confirmed. The identity of temperatures of the fixed loss of the specimen mass as well as the high thermostability of gelatin and finegrained Ukrainian hide powder have been revealed; coarse-grained Ukrainian hide powder is more sensitive to the influence of high temperature, whereas the foreign (Dutch) hide powder has the lowest thermostability. The regularities of thermal destruction of the analyzed collagen preparations can be explained by the peculiarities of their structure, including the amino acid composition, particle shape and size conditioned by their origin and method of manufacture. The obtained results will contribute to a more efficient use of primary and secondary collagen-containing raw materials.

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The study presents the extraction of collagen, a product of high value, from fleshings form hides. After testing several collagen extraction procedures we have proposed the simple and effective method to extract collagen from collagen-containing wastes of the leather industry. The unified method is based on the extraction of collagen using acetic acid in the presence of EDTA and included two repeated extraction stages. Qualitative analysis of the collagen using the disk-electrophoresis method showed a different ratio of monomers, dimers and other proteins.