Leather and Footwear Journal

Volume 22, no 3

Contents
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ESTIMATION OF THE REGIMES OF ABLATION OF THE FABRIC OF KARAKUL FOR GLUTARALDEHYDE TANNING UNDER THE EXPOSURE OF A LASER ON YTTRIUM ALUMINUM GARNET
- Pages 159-168
  Juma Sharopovich AZIMOV¹, Maria Ivanovna MARKEVICH², Tulkin Jumaevich KODIROV³, Shokhrukh Shukhratovich SHOYIMOV^{1, *}, Akmal Yusupovich TOSHEV³
  - ¹Bukhara Institute of Engineering and Technology, 200100, K. Murtazaev street 15, Bukhara, Republic of Uzbekistan, e-mail: shoyimovshsh@mail.ru
  - ²Physical-Technical Institute of the NAS of Belarus, 220141, Academician Kuprevich street 10, Minsk, Belarus
  - ³ashkent Institute of Textile and Light Industry, 100100, Shohzhahon-5, Tashkent, Republic of Uzbekistan, e-mail: akmal-toshev-yu@mail.ru
  ABSTRACT. The article discusses the activation of the surface of karakul (astrakhan) leather tissue by laser exposure, changes in the surface morphology of karakul leather tissue during laser processing and subsequent glutaraldehyde tanning combined with chrome tanning of karakul leather. The morphology of the surface of the sample was investigated by the methods of optical and scanning electron microscopy and the elemental analysis of the skin tissue of karakul under the action of laser radiation from the front side was carried out. Dry tanning was carried out after laser exposure. For the first time, the morphology of the surface of the skin tissue of karakul was investigated using a laser generating in a two-pulse mode (pulses are separated by a time interval of 3 μs, pulse duration of 10 ns) with a wavelength of 1064 nm in a wide range of deposited energies, which lead, as to the mode of ablation of the surface of the skin tissue of karakul and to its perforation followed by glutaraldehyde tanning. The possibility of changing the consumer parameters of the skin tissue of karakul due to the dermis dissociation, conformational changes, which lead to a change in the structure, is shown. At energies more than 30 J, the skin is perforated with carbonization of the edges of the holes.
  
  KEY WORDS: Karakul skins, glutaraldehyde, morphology, hydrothermal destruction, laser radiation
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OBTAINING BIOEMULSIONS STRUCTURED AS “NETWORKS” BY INNOVATIVE TECHNOLOGIE
- Pages 169-174
  Demetra SIMION^{1, *}, Carmen GAIDĂU¹, Gabriela PĂUN², Maria STANCA¹, Daniela BERECHET¹
  - ¹INCDTP – Division: Leather and Footwear Research Institute, 93 Ion Minulescu st., 031215, Bucharest, Romania
  - ²National Institute for Research-Development of Biological Sciences, 060031 Bucharest, Romania
  ABSTRACT. New bioemulsions structured like “networks” were created by innovative technologies based on: elastin/zinc hydroxide/ (bolaamphiphiles mixture: bis [2-butyl (sodium bis-thioacetate) sodium dicarboxylate 1,10 decanediyl ester] and/or sucrose diester)/ acetic acid/water, for improved surface properties development with applications in leather industry. We used in this research two “bolaamphiphiles”. Bolaamphiphilic molecules contain a hydrophobic skeleton (e.g., one, two, or three alkyl chains, a steroid, or a porphyrin) and two water-soluble groups on both ends. The interaction of surfactants with biopolymers in aqueous medium results in the formation of different association structures. There are various morphologies of biopolymer-surfactant association complexes depending on the molecular structure of the biopolymer and surfactant, on the nature of interaction forces between solvents and surfactant or biopolymer. The innovation consists in the technologies for obtaining novel micro and nanostructured bioemulsions, and the compatibilisation with film forming polymers for leather surface finishing. Elastin/zinc hydroxide micro and nanocomposites have been stabilized with bolaamphiphilic surfactants mixture: bis [2-butyl (sodium bis-thioacetate) sodium dicarboxylate 1,10 decanediyl ester and sucrose diester in a 1:1 acetic acid/water ratio, to increase the uniformity of nanocomposites. Micro and nanostructured composites like “networks” developed as a result of biopolymer-surfactants interactions for elastin/zinc hydroxide/surfactants mixture couple in acetic acid/water system are reported by SEM microscopy and DLS analysis. A special class of micro and nanoarchitectures is represented by structures organized as “network” assemblies. The novel micro and nanocomposites can provide the hybrid film with increased resistance to rubbing and water, and to deformation. Environmentally-friendly substrates with smart multifunctional features can be obtained for various applications.
  
  KEY WORDS: bolaamphiphiles, bioemulsions structured like “networks”, innovative technologies, improved surface properties
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THE VALIDITY AND RELIABILITY OF TRUEDEPTH CAMERA EMBEDDED IN THE PHONE FOR FOOT MEASUREMENT
- Pages 175-184
  Qian LU¹, Shunxun LI¹, Jin ZHOU^{1, *}, Zhifeng YAO², Wei LI²
  - ¹Sichuan University, College of Biomass Science and Engineering, National Engineering Laboratory for Clean Technology of Leather Manufacture, Section of Chengdu No. 24 Southern Yihuan, 610065, Chengdu, China, zj_scu@scu.edu.cn
  - ²Beijing Luxcreo, Inc., Beijing, P.R. China
  ABSTRACT. There are several laser or structured-light based foot scanners available on the market, which can be used to obtain accurate 3D foot models. Compared to those 3D scanning devices, TrueDepth cameras are portable, inexpensive and easy-to-use. However, the accuracy and reliability of their 3D foot scanning remain to be confirmed. This study aimed to verify the validity and reliability of structured light TrueDepth camera integrated into the mobile phone when it is used for foot measurement. Thirteen students without any kinds of foot abnormalities or foot diseases were recruited and their feet were measured by both Infoot 3D foot scanner and mobile phone with TrueDepth camera. Three parameters were measured including foot length, foot breadth and ball girth. Subsequently, the reliability and validity of the two methods were assessed by linear regression analyses, intraclass Correlation Coefficient and Bland-Altman analysis. The foot breadth and girth circumference measurements all showed high coefficients of determination (R2 >0.8) between the two methods and three measurements indicated good to excellent agreements (ICCs>0.9), although the length measurement was reported without significant coefficients of determination. Further, findings from Bland-Altman analysis demonstrated that the measurements from the TrueDepth camera had good agreements with those from Infoot and they could be used interchangeably. However, with the reconstruction algorithm updating in the near future, we could foresee the promotion in foot length measurement when using the TrueDepth camera from the phone. The TrueDepth camera utilizing structured-light and the customized application for foot measurement has fast, accurate and low-cost features and it is a convenient and economical method to obtain the foot 3D model. It can be widely applied for medical purposes and customization.
  
  KEY WORDS: foot measurement, foot 3D model, structured-light, TrueDepth camera
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ENZYMATIC BIOTECHNOLOGY APPLIED TO PELT WASTE
- Pages 185-196
  Rodica Roxana CONSTANTINESCU^{1, *}, Mariana FERDEȘ², Mădălina IGNAT¹, Ciprian CHELARU¹, Ana-Maria CIOBANU¹ , Denis DRUȘAN¹
  - ¹INCDTP – Division: Leather and Footwear Research Institute, 93 Ion Minulescu st., 031215, Bucharest, Romania, rodica.roxana@yahoo.com
  - ²University Politehnica Bucharest, marianaferdes@yahoo.com
  ABSTRACT. Enzymes are the substances that speeds up a chemical reaction suitable for green chemistry and can be used to achieve ecological industrial processing in order to reduce the effects of industrial pollution. Microbiological degradation of pelt waste is amongst the permanent concerns of tanners. Several enzymes have been used in the leather industry to substitute the conventional process, mainly proteases. The objectives of this study were to isolate and identify bacteria which produced protease enzyme from tannery solid waste. The selected bacterial strains showed increased protease biosynthesis capacity, which had a significant hydrolytic action on pelt waste. The results obtained in this study demonstrated the ability of strains belonging to the Bacillus genus to synthesize increased amounts of proteolytic enzymes and to degrade pelt waste, as well as the possibility of using these microorganisms as a source of protease in various biotechnological processes.
  
  KEY WORDS: leather waste, isolation of bacteria, protease enzyme
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POLYMER COMPOSITE BASED ON NATURAL RUBBER AND FUNCTIONALIZED RUBBER WASTE
- Pages 197-208
  Laurenţia ALEXANDRESCU*, Mihai GEORGESCU, Maria SÖNMEZ, Mihaela NIȚUICĂ, Maria-Daniela STELESCU, Dana GURĂU
  - INCDTP - Division: Leather and Footwear Research Institute, 93 Ion Minulescu St., sector 3, Bucharest, Romania, laurentia.alexandrescu@icpi.ro
  ABSTRACT. In this work, biodegradable polymer composites were made based on natural rubber and post-consumer vulcanized rubber waste functionalized with potassium oleate, in various proportions (5, 10, 20, 30, 50%), cryogenically ground to dimensions of min. 500 nm and polyethylene grafted with maleic anhydride as compatibilizer between the two phases. This composite will be made into a low-density product, with low cost, and last but not least, biodegradable, with the recovery and reuse of waste, containing post-consumer polymers. The methodology for making the new materials involves the following steps: sorting waste, grinding, functionalization and compounding. These operations are easy to manage and do not involve new equipment. Compounding, the most important operation, is carried out on a roller and the mixtures are processed into finished products by compression in an electric press. The tested biodegradable composites were structurally and physico-mechanically characterized. Waste transformation (ground and functionalized) into new value-added products will lead to remarkable improvements in the life cycle of raw materials and the sustainable use of this waste, contributing to sustainability, improving eco-efficiency and economic efficiency and reducing the “pressure” of waste on the environment.
  
  KEY WORDS: biodegradability, polymer composite, post-consumer
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TESTING OF MEDICAL SHEEP FUR WITH ANTIMICROBIAL PROPERTIES – PART 1
- Pages 209-216
  Olga NICULESCU*, Rodica Roxana CONSTANTINESCU, Dana GURĂU
  - INCDTP – Division: Leather and Footwear Research Institute, 93 Ion Minulescu St., Sector 3, Bucharest, Romania, e-mail: o_niculescu@yahoo.com
  ABSTRACT. The medical treatment of patients with rheumatic, joint and muscle diseases can be improved by alternative methods. The essential oils extracted from different plants have certain analgesic, anti-inflammatory, antiseptic, antibacterial, immunostimulating properties, etc. Products have been made based on essential oils with therapeutic properties (mint, cajeput, eucalyptus), which can be used to treat the surface of finished sheep fur for medical purposes. The sheep furs were tanned (without metals) with syntans based on phenolsulfonic acids and aromatic oxysulfones and treated with products based on essential oils with therapeutic properties, to be used to make medical fur articles (lumbar and cervical belts, knee pads, elbow pads, etc.). They can improve rheumatic, muscular and circulatory conditions, complementing the medical treatment of patients suffering from these conditions. The work presents the chemical, physical-mechanical and microbiological characterization of natural furs for medical use.
  
  KEY WORDS: medical fur, essential oils, antimicrobial properties
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PREPARATION OF ELASTIN MEMBRANES BASED ON SURFACTANTS AND SEPARATION MECHANISM
- Pages 217-222
  Demetra SIMION^{1, *}, Carmen GAIDĂU¹, Gabriela PĂUN²
  - ¹INCDTP – Division: Leather and Footwear Research Institute, 93 Ion Minulescu st., 031215, Bucharest, Romania, demetra.simion@yahoo.com
  - ²National Institute for Research-Development of Biological Sciences, 060031 Bucharest, Romania
  ABSTRACT. The influence of a classical surfactant – palmitoyl-glycylglycine and bola amphiphilic – demecarium bromide upon the elastin membrane preparation and separation mechanism of turmeric from aqueous solutions was studied by: UV-VIS spectroscopy, scanning electron microscopy, dynamic light scattering and separation rates. The tensile strength and hydrophobic property were improved by introducing a surfactant (classic or bola). In this research the influence of surfactants upon the microporous structure and retention of turmeric from aqueous solutions was studied. The biomembranes were produced by a casting-solvent evaporation technique. The elastin powder was dissolved in a water-acetic acid (70:30 v/v) solution with and without plasticizer: glycerol and surfactant (classic or bola), constant continuous stirring for 5-7 hrs. at 60°C, then degassed the solution for 2 hrs. The solution was poured and afterwards maintained in the oven at 45-55°C for 5-8 hrs. Ecological biomembranes are obtained from a biodegradable biopolymer – elastin, and can be used successfully in removing turmeric from wastewaters.
  
  KEY WORDS: elastin biomembranes, surfactants (classical and bolaform), separation mechanisms of turmeric from aqueous solutions
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BIODEGRADABLE POLYMERIC COMPOSITES BASED ON NATURAL RUBBER AND FUNCTIONALIZED POST-CONSUMER LEATHER WASTE
- Pages 223-235
  Laurenția ALEXANDRESCU*, Mihai GEORGESCU, Maria SÖNMEZ, Mihaela NIȚUICĂ, Maria Daniela STELESCU, Dana GURĂU
  - INCDTP - Division: Leather and Footwear Research Institute, 93 Ion Minulescu St., sector 3, Bucharest, Romania, laurentia.alexandrescu@icpi.ro
  ABSTRACT. This work presents the development and characterization of biodegradable polymeric composites based on natural rubber and protein waste from finished post-consumer leather. Protein waste is cryogenically ground to min. 500 nm, functionalized by a mechanical process at temperature with potassium oleate (5%) and mixed in the composite in various proportions (5, 10, 20, 30, 50%). This composite will be made into a low-density product, with low cost, recovery and reuse of waste, and last but not least, biodegradable. The methodology for making the new materials involves the following steps: sorting waste, grinding, functionalization and compounding. These operations are easy to manage and do not involve new equipment. Compounding, the most important operation, will be carried out on a roller and the mixtures will be processed into finished products by compression in an electric press. The tested biodegradable composites were structurally and physico-mechanically characterized. Waste transformation (ground and functionalized) into new value-added products will lead to remarkable improvements in the life cycle of raw materials and the sustainable use of this waste, contributing to sustainability, improving eco-efficiency and economic efficiency and reducing the “pressure” of waste on the environment.
  
  KEY WORDS: protein waste, polymer composite, biodegradability
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