Leather and Footwear Journal

Volume 26, no 1

Contents
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OBTAINING COLLAGEN HYDROLYZATES FROM SECONDARY PRODUCTS OF CHROME-TANNED LEATHER
- Pages 3-10
  Ulbosin ESHBAEVA JAMALOVNA¹, Gökhan ZENGIN², Bahri BAŞARAN², Nargiza ALIYEVA BAXTIKHOZIYEVNA^1*
  - ¹Namangan Institute of Engineering and Technology, Uzbekistan, email: nargis_03@mail.ru
  - ²Faculty of Engineering, Ege University, Türkiye
  ABSTRACT. In many tanneries, chrome-tanned leather shavings are still viewed as waste, despite their high collagen content and potential for reuse. This study focused on developing a process to extract collagen hydrolysates from these shavings using alkaline hydrolysis. The lab work involved several phases of testing with NaOH, KOH, and Ca(OH)₂ under different concentrations and temperatures, followed by further purification using barium chloride. The results of the study showed that chromium levels dropped dramatically, and the collagen that remained had strong adhesive properties, measured using standard surface tension and contact angle methods. Early experiments showed swelling issues and filtration delays, which the researchers had to troubleshoot by adjusting hydrolysis time and alkali ratios. But by the final stage, the method proved reliable. The broader takeaway here is that collagen recovery from chrome waste could not be just chemically viable—it could also offer real industrial and environmental value if adopted more widely.
  
  KEY WORDS: adhesive properties, alkaline hydrolysis, chrome-tanned leather, collagen hydrolysates, waste recycling
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TATTOO AS A WAY OF FINISHING VEGETABLE-TANNED CRUST LEATHER
- Pages 11-26
  Megabi Adane YIZENGAW^1*, Tamrat TESFAYE^2*
  - ¹Leather Engineering Department, Ethiopian Institute of Textile and Fashion Technology, P.O.Box: 1037, Bahir Dar University, Bahir Dar, Ethiopia, email: megadane123@gmail.com2Textile Chemical Process Engineering Department, Bahir Dar University, Ethiopian Institute of Textile and Fashion Technology, P.O.Box: 1037, Bahir Dar, Ethiopia
  - ²Textile Chemical Process Engineering Department, Bahir Dar University, Ethiopian Institute of Textile and Fashion Technology, P.O.Box: 1037, Bahir Dar, Ethiopia
  ABSTRACT. Leather embellishment is a rich art form that can create diverse functional products. Traditional and modern techniques manipulate leather fibers to create precise designs and require careful handling due to leather's intricate structure. This study focused on optimizing and evaluating the compatibility of tattooing inks and application techniques with vegetable-tanned crust leather. Two commercially available inks, Dynamic Ink Triple Black 240ml and Super Black Ink, were assessed for pH and color fastness to rubbing, and Dynamic Ink Triple Black 240ml demonstrated superior color fastness. Next, the conditions for applying the tattoo were optimized, and its effect on the leather structure and properties was studied. The impact of cleaning alcohol concentration, needle speed, and the number of finishing agent coats on color fastness to rubbing (dry and wet) characteristics of tattooed leather was optimized using Design-Expert version 13. It indicated that higher cleaning alcohol concentration and needle speed negatively affected color fastness, while more coats of the finishing agent improved it. Post-tattooing, the tensile strength slightly decreased from 17.8 N/mm², to 17.3 N/mm², elongation reduced from 28.40% to 27.70%, and tear strength marginally decreased from 25.0 to 24.7 N/mm. Abrasion resistance tests showed slight damage to the leather after tattooing, indicating some weakening of the surface structure. Despite these changes, the leather maintained high durability and flexibility. FTIR analysis revealed the formation of new and modification of existing chemical compounds in the collagen structure as a result of the interaction of ink components with leather. Overall, this study demonstrates the feasibility and durability of tattooing vegetable-tanned cowhide crust leather using Dynamic Ink Triple Black 240ml, providing optimal results in terms of color fastness and minimal impact on the leather's structure and properties.
  
  KEY WORDS: finishing, vegetable-tanned leather, tattoo, tattoo ink
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SYNTHESIS OF CHITOSAN BEADS/ACTIVE CHARCOAL AS ADSORBENT OF YELLOW ACID 25 AND ACID RED 73
- Pages 27-36
  WIJAYANTI, Elis NURBALIA, Wahyu Fajar WINATA^*, Prasetyo HERMAWAN
  - Program Studi Teknologi Pengolahan Kulit, Politeknik ATK Yogyakarta, Indonesia, email: wahyufajarwinata88@gmail.com
  ABSTRACT. Synthesis of chitosan/activated carbon beads has been carried out as an adsorbent for Acid Yellow 25 and Acid Red 73 in the solution. The adsorbent preparation was carried out by dissolving chitosan in 2.5% (v/v) acetic acid and then adding activated carbon. The beads were printed in NaOH solution and then washed until neutral. Chitosan/activated carbon bead adsorbents were characterized using FTIR and SEM before and after the adsorption-desorption process. Optimum conditions were determined by adsorption studies at various contact times, initial concentrations, and pH for each dye. Desorption studies were carried out using NaOH desorption medium at various concentrations and desorption times. The results showed that the optimum adsorption conditions for AY-25 were a contact time of 90 minutes with an initial concentration of 600 mg L^–1 at pH 4 which resulted in an adsorption capacity of 501.8 mg g^–1. Meanwhile, AR-73 was optimum at 120 minutes with an initial concentration of 300 mg L^–1 at pH 4 which resulted in an adsorption capacity of 297.5 mg g^–1. The adsorption of the two dyes followed the pseudo-second-order kinetic model and agreed with the Langmuir isotherm model. The effective desorption process was carried out with 1 M NaOH for 3 hours. The regenerated adsorbent can be used for the adsorption process three times.
  
  KEY WORDS: adsorption, chitosan beads/activated carbon, Acid Yellow 25, Acid Red 73
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CHALLENGES IN PROTECTIVE FOOTWEAR FOR INDIA'S DISASTER MANAGEMENT WORKFORCE: A DESIGN THINKING APPROACH
- Pages 37-50
  Arun Kumar GAIKWAD^*, Adity SAXENA
  - Woxsen University, Telangana, India, arunkumar.gaikwad@woxsen.edu.in, Dean.SD@woxsen.edu.in
  ABSTRACT. Firefighters in India play a critical role in managing fire accidents and rescue operations, often working under high-pressure and hazardous conditions. Their work demands swift and efficient action, making it essential to ensure their safety and performance through appropriate equipment, particularly footwear. Footwear is a crucial component of their protective gear, directly impacting their mobility, comfort, and overall effectiveness during rescue operations. This study explores the current challenges associated with the footwear used by disaster management professionals in India, with a specific focus on firefighters. It evaluates the design, functionality, and performance of the footwear currently in use and identifies the limitations that hinder their effectiveness in extreme conditions. The research adopts a design thinking approach to analyze the challenges faced by disaster management professionals through a comprehensive mixed-methods study. A structured survey was conducted with 385 disaster management professionals across Six Indian states (Telangana, Maharashtra, Karnataka, Tamil Nadu, west Bengal and Gujarat), complemented by in-depth interviews with 75 firefighters from various operational levels. Additionally, a systematic literature review was conducted. Data were gathered on various factors, including comfort, durability, protection, flexibility, and environmental adaptability of the footwear. Findings reveal near-unanimous consensus on the need for footwear redesign, with 96.1% of respondents in agreement. Poor heat and flame resistance emerged as the dominant performance deficiency, identified by 34.8% of respondents. Chi-square analysis confirmed a highly significant association between reported challenges and redesign necessity (χ² = 28.47, p < 0.001, Cramér's V = 0.272). K-means cluster analysis identified three operationally distinct user personas, affirming that a single uniform specification is insufficient for India's heterogeneous disaster management workforce. Evidence-based design specifications were translated into two functionally differentiated prototypes. Design A, a low-mid ankle boot incorporating the patent-pending Protected Rapid-Release Closure System, achieved full IS 15298 (Part 2):2024 compliance across all mandatory test parameters, with breathability exceeding Indian market norms. Design B, a tall shaft boot configured for wildland deployment, incorporated an external TPU ankle panel with documented protection-mobility trade-offs. Both prototypes were validated at a BIS-approved laboratory, utilising an Indian-specific anthropometric last and a nine-component material architecture, demonstrating the feasibility of IS 15298-compliant next-generation protective footwear within Indian manufacturing constraints.
  
  KEY WORDS: firefighting footwear design, protective footwear, occupational safety, design thinking, ergonomics, India disaster management
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