Leather and Footwear Journal

Volume 26, no 3

Contents
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DYNAMIC STUDY OF THE FEET IN PATIENTS WITH TYPE 2 DIABETES MELLITUS AND THE DESIGN OF INDIVIDUAL ORTHOPEDIC INSOLES CONSIDERING LOCALLY OVER-PRESSURE AREAS
- Pages 139-154
  Merab SHALAMBERIDZE^1*, Malvina TATVIDZE2²
  - ¹Department of Design and Technology, Akaki Tsereteli State University, 59 Tamar Mepe Str., Kutaisi 4600, Georgia, merab.sh@hotmail.com
  - ²Department of Chemical and Environmental Engineering, Akaki Tsereteli State University, 59 Tamar Mepe Str., Kutaisi, 4600, Georgia, m.tatvidze@yahoo.com
  ABSTRACT. This paper presents a dynamic study of the feet of patients with type 2 diabetes mellitus, as well as the design and manufacture of individual orthopedic insoles, taking into account locally overpressure areas. As a result of pedographic investigation, overpressure areas in the plantar side of the diabetic foot were identified. These locally overpressure areas were marked on the pedogram by curves when the pressure exceeded 150 kPa. A mathematical approach based on integral curves derived from the solution to Dirichlet singular boundary problem was applied to describe the overpressure areas with high precision. Based on the proposed mathematical algorithm, the software package was developed. Individualized orthopedic insoles were manufactured using silicone polymers and ethylene-vinyl acetate polymers of varying degrees of hardness. Soft polymer composites were used for locally overpressure areas, while relatively rigid material for the insole frame providing stability. Individual orthopedic insoles were produced on a computer numerical control milling machine taking into account locally overpressure areas. Individual orthopedic insoles manufactured using these technologies effectively reduce locally overloaded areas on the plantar surface of the foot and protect the foot from mechanical damage. The production and practical use of individual orthopedic insoles, developed on the basis of the research findings, contribute to the effective treatment and prevention of complications in patients with diabetic foot.
  
  KEY WORDS: diabetic foot, foot plantar pressure area, pedograph method, individual orthopedic insoles
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A SYSTEMATIC APPROACH TO TEXTILE DESIGN: AN EXPERIMENTAL STUDY
- Pages 155-176
  Pinar ARSLAN^*, Ozge OZTURK
  - Ankara Hacı Bayram Veli University, Faculty of Art and Design, Department of Textile Design, 06830, Ankara, Türkiye, pinar.arslan@hbv.edu.tr, ozturk-ozge@hbv.edu.tr
  ABSTRACT. Systematic creativity models provide structured frameworks for defining design problems, generating ideas, and evaluating solutions. Among these models, Osborn’s Seven-Stage Theory offers a step-based process that supports creative thinking and problem-solving. This study aims to examine the applicability of Osborn’s model in textile pattern design through an experimental approach. The research was conducted with second-year students from the Textile Design Department at Ankara Hacı Bayram Veli University. Within the scope of the study, seven students developed textile pattern designs by systematically applying the stages of Osborn’s model. The resulting designs and processes were analyzed in terms of originality, conceptual consistency, and creative diversity. The findings indicate that the structured implementation of the model enhances systematic thinking, supports creative exploration, and contributes to the development of more original and coherent textile patterns. The study proposes a methodological framework for integrating systematic creativity models into textile design practice and education, thereby contributing to innovation-oriented design processes in the textile field.
  
  KEY WORDS: digitalization; fabric design; innovation; creative process; pattern
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INFLUENCE OF FATLIQUOR CHEMISTRY ON FOGGING AND ODOUR CHARACTERISTICS OF AUTOMOTIVE LEATHER: A COMPARATIVE STUDY OF COMMERCIAL FATLIQUOR
- Pages 177-188
  Ali YORGANCIOGLU^*
  - Ege University, Faculty of Engineering, Department of Leather Engineering, 35100, Izmir, Turkiye, e-mail: ali.yorgancioglu@ege.edu.tr
  ABSTRACT. Fogging and odour emissions are among the most important quality requirements for automotive leather due to their direct impact on passenger comfort, interior air quality and driving safety. Fatliquors are indispensable components in leather manufacture, providing softness, flexibility, fullness and durability; however, they are also recognized as one of the major sources of volatile substances responsible for fogging and odour formation. Therefore, the selection of appropriate fatliquor systems is critical for the production of automotive leathers with low emission characteristics. In this study, commercially available fatliquors supplied by three different suppliers with different chemical compositions, including phosphoester-based, fish-oil-based, ester-based, lecithin-containing and synthetic formulations were comparatively evaluated. Automotive leathers prepared with these fatliquors were characterized in terms of fogging behaviour according to DIN EN ISO 17071 and odour performance according to the VDA 270 method. In addition, the effects of fatliquor chemistry on the physical performance of leather were assessed through tensile strength, tear strength and colour fastness with accelerated ageing analysis. The results revealed substantial differences among the evaluated fatliquors in terms of fogging and odour performance. Gravimetric fogging values ranged from 6.8 to 20.8 mg, with synthetic oil, phosphoester and lecithin-based fatliquors generally showing relatively lower fogging tendencies, whereas certain fish oil and ester-based formulations exhibited comparatively higher fogging values. Odour ratings varied between 3.0 and 4.5, and no direct relationship was observed between fogging and odour performance. Notably, considerable differences were also observed among commercial products belonging to the same chemical class, indicating that formulation-specific characteristics play an important role in emission behaviour. These findings demonstrate that fatliquor chemistry and formulation characteristics should be carefully considered when selecting low-emission fatliquors for automotive leather..
  
  KEY WORDS: automotive leather, fatliquor, fogging, odour emission, strength
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DEODORIZATION OF LEATHER TANNERY WASTE WATER TOXIC GASES USING SPENT COFFEE GROUNDS: A COMPREHENSIVE REVIEW
- Pages 189-206
  Megabi Adane YIZENGAW^*
  - Leather Engineering Department, Ethiopian Institute of Textile and Fashion Technology, P.O. Box: 1037, Bahir Dar University, Bahir Dar, Ethiopia, email: megadane123@gmail.com
  ABSTRACT. The leather tanning industry is a major contributor to economic development worldwide; however, it is also associated with significant environmental challenges, particularly the generation of toxic and malodorous gases from wastewater treatment processes. Emissions such as hydrogen sulfide (H₂S), ammonia (NH₃), and volatile organic compounds (VOCs) not only create severe odor nuisances but also pose substantial risks to human health, workplace safety, and environmental quality. Conventional odor control technologies, including chemical scrubbing, activated carbon adsorption, and biological filtration, often suffer from high operational costs, energy demands, and secondary waste generation, highlighting the need for sustainable alternatives. This review critically examines the potential of spent coffee grounds (SCG), an abundant agro-industrial by-product, as an innovative and eco-friendly adsorbent for deodorizing tannery wastewater gases. Owing to their porous structure, high carbon content, and rich surface chemistry containing hydroxyl, carboxyl, and phenolic functional groups, SCG exhibit remarkable capabilities for capturing and transforming hazardous gaseous pollutants through physical adsorption, chemisorption, and redox mechanisms. The review discusses the sources and formation pathways of toxic tannery gases, evaluates existing odor control technologies and their limitations, and explores the physicochemical characteristics and gas-removal mechanisms of SCG. Furthermore, it highlights current research advances, regeneration potential, and opportunities for integrating SCG into sustainable wastewater treatment systems. Although challenges related to adsorption efficiency, material standardization, and large-scale implementation remain, the valorization of spent coffee grounds represents a promising circular-economy strategy that simultaneously addresses waste management and industrial air pollution.
  
  KEY WORDS: leather tannery wastewater, spent coffee grounds, odor control, adsorption, circular economy
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MECHANICAL BEHAVIOR OF BELT LEATHERS PRODUCED WITH DIFFERENT TANNING SYSTEMS
- Pages 207-216
  Fatih Furkan YILDIZ¹, Fatih YALÇIN², Nilay ORK EFENDIOGLU^1*, Hüseyin Ata KARAVANA¹
  - ¹Ege University, Faculty of Engineering, Department of Leather Engineering, 35100, İzmir, Türkiye, nilay.ork@ege.edu.tr
  - ²Usak University, Technology Transfer Office, 64100, Usak, Turkey, fatih.yalcin@usak.edu.tr
  ABSTRACT. In this study, the effects of different tanning systems on the mechanical behavior of bovine belt leathers were comparatively investigated. Heavy bovine pickled hides were subjected to three commercial tanning systems: System I (Vegetable-based combination: 10% Mimosa + 10% Quebracho), System II (Synthetic-based combination: 10% Phenolic syntan + 15% White syntan), and System III (Chrome-focused combination: 7% Basic chromium sulphate + 10% Phenolic syntan). Following post-tanning, leather samples were evaluated according to TS EN ISO standards. Statistical analysis was performed using one-way ANOVA followed by Tukey’s post-hoc test (p < 0.05) to determine significant differences among tanning systems. Experimental findings demonstrated that the tanning system plays a definitive role on leather performance. Tanning System III leathers exhibited superior mechanical properties, recording the highest mean thickness (3.80±0.06 mm), tensile strength (25.34±3.64 N/mm²), double edge tear strength (361.57±34.08 N), grain cracking force (65.00±15.00 kgf), grain bursting force (100.00±7.21 kgf), and stitch tear resistance (509.61±80.54 N). Furthermore, they displayed 0.00% extension set, indicating excellent dimensional stability required for premium belt production. Conversely, Tanning System II leathers demonstrated the highest elasticity with an elongation at break of 69.74±16.34% and a comparable single edge tear load (90.42±15.09 N) but displayed an extension set of 1.30±0.42%. Tanning System I leathers overall exhibited lower mechanical strength (tensile strength: 20.75±6.67 N/mm²; highest extension set: 2.22±1.53%), though they offered superior grain crack (12.71±0.57 mm) and bursting distension (15.41±0.34 mm). Under the conditions investigated, System III provided the most favorable overall mechanical performance for heavy-duty belt leather, while the specific synthetic and vegetable formulations used in Systems II and I, respectively, provided greater extensibility and grain distension. These findings are specific to the commercial tanning formulations investigated and should not be generalized to all vegetable, synthetic, or chrome tanning systems.
  
  KEY WORDS: belt leather, chrome tanning, vegetable tanning, synthetic tanning, mechanical properties
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CONDUCTIVE TEXTILES FOR ELECTROMAGNETIC SHIELDING: A SHORT REVIEW
- Pages 217-228
  Cornel Adrian MARIN^*, Raluca Maria AILENI
  - The National Research & Development Institute for Textiles and Leather, 030508, Bucharest, Romania, email: adrian.marin@incdtp.ro
  ABSTRACT. The increasing use of electronic devices and wireless communications has generated growing demand for efficient electromagnetic interference (EMI) shielding materials. Traditional metallic enclosures, while effective, are heavy and rigid, limiting their use in modern wearable and flexible applications. Functionalized textiles have emerged as a versatile alternative, combining flexibility, low weight, and adaptability to complex geometries with effective EMI attenuation. This review provides a comprehensive, up-to-date analysis of conductive textile systems for EMI shielding, with explicit treatment of the underlying shielding mechanisms – reflection loss (SEr), absorption loss (SEa), and multiple internal reflections (SEMIR). Major material categories are systematically discussed: metallic fiber fabrics, metal-coated textiles, intrinsically conducting polymer coatings, carbon-based nanomaterial systems, MXenes, and hybrid multi-layer architectures. Consolidated comparative tables of material performance and fabrication methods are provided as practical references. Practical challenges of washability, scalable manufacturing, standardization, and biocompatibility are discussed. Reported shielding effectiveness (SE) values range from ~5 dB for simple conductive-polymer coatings to over 100 dB for advanced hybrid multi-layer composites.
  
  KEY WORDS: conductive polymers, metal-coated fabrics, flexible shielding, nanomaterials, MXene, EMI shielding effectiveness, wearable textiles
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COMPACT THERMOPLASTIC POLYMER BIOCOMPOSITE BASED ON PE/PE-G-MA/EPDM/CF AND DYNAMICALLY VULCANIZED WITH DICUMYL PEROXIDE
- Pages 229-236
  Laurenția ALEXANDRESCU^*, Mihai GEORGESCU, Maria SÖNMEZ
  - Rubber Research Department, National Research and Development Institute for Textiles and Leather – Division: Leather and Footwear Research Institute, 93 Ion Minulescu st., district 3, Bucharest, Romania, laurentia.alexandrescu@icpi.ro
  ABSTRACT. Polymer biocomposites are considered a way to stimulate the creation of a new type of material with much improved properties, which economically and efficiently combines the properties of at least two polymers (elastomer and plastomer) and natural reinforcing materials, which are component elements of composite materials, intended to improve their mechanical, thermal or chemical properties. This paper presents the development of dynamically vulcanized thermoplastic biocomposites, with anti-thermal and antimicrobial characteristics, using circular economy concepts for the development of “green” polymer composites, with market demand in niche areas of significant economic activity for the industry, while respecting the requirements of the economic and social environment. Dynamically vulcanized multiphase elasto-plastic polymer biocomposites are reinforced with natural calcium carbonate waste for products used in the food and pharmaceutical fields, based on elastomer (ethylene propylene terpolymer rubber – EPDM) and calcium carbonate waste dispersed in a plastomer matrix (high-density polyethylene – HDPE). The natural calcium carbonate waste was obtained from seashells, cryogenically ground to a particle size of 200-300nm and functionalized with polydimethylsiloxane (PDMS). The elastomers and calcium carbonate waste, through their micrometric dispersion in the plastomer matrix, led to the obtaining of a high-performance polymeric material with multifunctional characteristics (rubber and thermoplastic) and processing properties specific to plastics. The new material can be recycled for at least 5 cycles, without modifying its physical and mechanical properties. The experimental composites were characterized physically and mechanically by standardized methods specific to plastics.
  
  KEY WORDS: biocomposites, dynamically vulcanized thermoplastic polymer, calcium carbonate waste, eco-design
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