For military leather processing pinnacle technologies are applied, because the leather must have extreme hydrophobicity, herewith to maintain the breathability and moisture management capabilities. Therefore, leather producers must use such tanning chemicals, which are able to impart sufficient waterproofness and vapour permeability. In this study the influence of retanning and fatliquoring technologies for wet-blue hide conversion into finished military leather on its waterproofing behaviour and breathability has been studied. The comparable evaluation of leathers manufactured in Lithuanian and Kazakhstan tanneries was carried out. The leathers were characterized by chemical analysis and moisture absorption, water vapour permeability and water vapour absorption properties.
Unfinished leather has high water vapour permeability and low waterproofness because of its natural porous structure. To modify the surface appearance and hide any defects, to improve physical properties, such as light and rub fastness, resistance to water, solvents, abrasion, etc., leather needs to be finished. In this study the influence of waterborne finishing agents on the waterproofness and breathability of the hydrophobic leather obtained using different retanning, waterproofing, neutralization and dispersing agents has been investigated. The leather was characterized using morphological analysis and permeability studies.
Protective footwear for occupational use conducts static electricity through the upper, linings, insole and outsole into the ground. Footwear must be made from appropriate material to reduce the possibility of electrocution and other electricity-related incidents. In this study the influence of footwear materials for the upper and lining components’ structure on their electrical properties was investigated. For investigations leather and various textile laminates were chosen. The thickness of leather coating, composition of textile laminates, the upper-lining system, and relative humidity of the environment on electrical resistivity changes were evaluated. Leather shows antistatic properties at standard humidity, but its electrical conductivity greatly increases at high humidity due to the presence of polar groups in the leather structure. Textile lining laminates composed of natural and synthetic fibres are insulators, but their systems with leather at high humidity show resistivity values close to antistatic materials. Leather acrylic coating decreases the electrical conductivity of materials.
In this work the effects of different crystallographic modifications of calcium carbonate (CaCO3) filler on the melt flow, mechanical properties, hydrolytic degradation, and shape memory behaviour of recycled low-temperature poly(e-caprolactone)-based polyurethane (rTPU) were evaluated. Composites were prepared by two-roll milling varying filler content from 2 wt % to 6 wt %. It was found that at temperature range from 20 °C to 50 °C CaCO3 fillers do not change Young’s modulus, they decrease tensile stress and deformation of rTPU, but improve its mechanical properties at elevated temperatures (up to 65 °C). rTPU melt flow index increases due to chain scission during the recycling and filler mixing with mill. Therefore, destruction temperature of rTPU is 20 °C lower than that of TPU. The CaCO3 does not change shape memory properties independently of filler type and transition from secondary shape to the primary shape at 70 °C temperature is completed within 17 s for both filled and unfilled rTPU. The investigation of hydrolytic degradation shows that CaCO3 only slightly increases degradation rate of rTPU.
The paper presents a method based on non – contact image analysis, which allows to simplify experimental process and increase measurement accuracy, identifying local deformations of woven material. Striving to gain accuracy of image analysis results, specimen preparation and deformation process fixation stages are of great importance. For the studies differently marked specimen groups were prepared. Their behaviour in process of tension was analysed using a special calibrated image acquisition system. Using digital images of deformed specimen the displacement of the marked surface elements - points and their shape changes were measured and material deformations in separate specimen parts (A and B) were described. According the obtained results zones of uniform deformations were established and it confirmed that stretched specimen was deformed unevenly. Mild deformations obtained in part A and the highest values of deformation recorded in the centre of part B: local deformations in the transverse to tension direction were set up to -42.9 % and 27.6 % of local elongation along tension direction. Results of local deformation variation explain buckling phenomenon of bias stretched fabric. Particular local deformation values allow us to describe behaviour of deformed material, bring opportunities to perform experimental and modelling comparison of the results. The suggested methodology could be applied for the investigation of differently deformed material behaviour.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.