Leather and Footwear Journal

Volume 9, no 2

Contents
- Contents PDF
Leather Evaluation by Optical Microscopy Methods
- Pages 75-86
  Lucreția MIU¹, Ciprian CHELARU¹, Mihaela VȊLSAN¹, Viktoriya PLAVAN²
  - ¹INCDTP Division Leather and Footwear Research Institute, Bucharest, Romania, email: icpi@icpi.ro
  - ²Technology and Design, Kiev, Ukraine, email: chemi@mail.kar.net
  ABSTRACT. Leather and parchment have been used from ancient times for manufacturing heritage items, mainly books and manuscripts of great value. For their restoration, materials compatible to the old ones must be used, processed in similar conditions, in order to avoid side effects. This is the reason why the entire international community is paying special attention to the development and restoration of cultural heritage. In the process of restoring and preserving leather and parchment heritage items, evaluating the degradation level of the material base is essential for the purpose of establishing both the degradation causes and the optimum intervention methods. Thus, various technologies are used to get information as complex and as complete as possible, by means of non-destructive, discretionary and non-invasive methods (optical microscopy and Micro Hot Table). The methods are specific to the museum field, being classified as non-invasive investigation types. Complex studies have been carried out due to the fact that the variations of the environment parameters together with other characteristics such as animal type, tanning method, fibrillar structure, surface degradation degree etc. influence the preservation or degradation state of leather heritage items. As a rule, the samples taken from areas exposed or unexposed to mechanical, physical and chemical factors in analyzed heritage items exhibit different degradation degrees. According to the degradation degree of the studied samples, there is a different contraction temperature range and thus tanning technologies with vegetable tanning extracts and combined tanning have been developed.
  
  KEY WORDS: Microscopy, contraction temperature, leather, MHT
Synthesis and Comparative Characterization of Aluminoborosilicate and Lead Glass by Sol-gel
- Pages 97-94
  Maryam KHOSRAVI SAGHEZCHI¹, Felora HESHMATPOUR¹, Hossein SARPOOLAKY²
  - ¹Department of Chemistry, K.N. Toosi University of Technology, Tehran, Iran, email: maryam_khosravi_s@yahoo.com
  - ²Department of Metallurgy and Material Engineering, Iran University of Science and Technology (IUST), Tehran, Iran
  ABSTRACT. Aluminoborosilicate and lead glasses were prepared by sol-gel technique using metalalkoxids at the very low temperature as it is required for glass synthesis. Sol-gel chemistry produces a variety of inorganic networks from metal alkoxide monomer precursors in soft chemical reactions. The sol containing TEOS converted to gel during drop wise addition of Al-alkoxide and the other precursors added until the final alcogel yielded. For the lead glass synthesis, lead salt was added in the last stage of gelation to prepare the lead containing alcogels. The samples (alcogel) were kept and dried at room temperature to set and then the shrunk xerogel heated quickly at 600°C to avoid crystallization. Heating and cooling should be fast (about 12°C per a minute) to prevent crystallization. The glass powders were characterized employing X-ray diffraction (XRD), and scanning electron microscopy (SEM) equipped with EDS analysis. Although, partial crystallization of the samples containing lead was observed, the XRD of the aluminoborosilicate and high containing lead glass were completely amorphous. The crystalline phase composition in low containing lead glasses as investigated was lead silicate, Pb2SiO4. SEM investigations of the high lead containing glass showed that it is spongelike and hollow, containing larger pores. There are sporadic large and small pores of almost 10 µm and ≤1µm diameters, but no distinct crystals can be seen.
  
  KEY WORDS: sol gel, lead glass, xerogel
The Dependency of the Diffusion Coefficient on the Nature of the Gas Molecule by Elongation-Stressed Polymeric Membrane
- Pages 95-103
  Mihai GEORGESCU, Mihaela VȊLSAN, Maria FICAI, Laura PANȚURU, Teodora DRAGOMIR, Ciprian CHELARU
  - INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, RO, email: icpi@icpi.ro
  ABSTRACT. The use of rubber, particularly silicone rubber, in the field of synthetic membranes is of special interest because of the strong permeability they allow. The high permeability of rubber membranes (permeability is the product of gas diffusion coefficient and its coefficient of solubility in the membrane) and silicone rubber respectively is attributed to the flexibility of bonds in the structure such as the siloxane bonds in silicone polymers. Starting from the concept that polymer fiber elongation affects the movement of the gaseous substance shifting through the polymer, by modifying the path covered by the gas molecule through the membrane, the diffusion coefficients for H2, CO2, N2 have been determined. The method used for this purpose is based on the performances and calculation ability of the gas permeability testing instrument, GDP-C made by Brugger Company in Germany. It is a modern and high-performance instrument connected to a computer, allowing the measurement of the gas transfer rate through a membrane, and with the help of the installed software, the lag time, solubility and diffusion coefficient can be determined. The two cabinets and the membrane support are the most important part of the device. The accurate results of this instrument make it possible to highlight the dependence of the gas diffusion on various parameters such as the gas molecule dimension and the membrane elongation degree, an important characteristic in the use of polymeric membranes.
  
  KEY WORDS: membrane separation, diffusion coefficient, H2, CO2, N2 permeation
Antifungal Compounds for Leather Part I. Synthesis of Benzothiazole Biocides for Bovine Hides
- Pages 104-117
  Maria-Marcela ȚÂRLEA¹, Mete Mehmet MUTLU², Behzat Oral BITLISLI², Bahri BASARAN², Arife Candas ADIGUZEL ZENGIN²
  - ¹INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, RO, email: icpi@icpi.ro
  - ²Ege University Faculty of Engineering Leather Engineering Department, Izmir, TR
  ABSTRACT. Leather is an organic material which, when wet, can suffer structural modifications, degradations due to micro organisms finding a favourable environment for development. That is why new solutions for protection against the main species of fungi are being sought, which can develop on wet-blue leathers during commercialization, particularly during sea transport. The paper presents the obtaining procedures of four new fungicide products, by sulphonation of derivatives of 2-amino-benzothiazole-6-substituted with methyl, methoxy, chlorine and nitro. By means of the sulphonation reaction, a single anionic sulphonic group is bonded in the molecule, which confers increased water solubility to the products and allows ionic bonding to the aminic group of bovine hides, thus ensuring their antifungal protection. The new benzothiazole biocide products were characterized by spectral analyses: UV spectra, IR spectra, MS mass spectra, RMN spectra, HPLC chromatography, as well as determinations of melting points. The characterization revealed that the products obtained by sulphonation of derivatives of 2-amino-benzothiazole-6-substituted with methyl, methoxy and chlorine are isomer blends of sulphonated acids in question, and the sulphonated acid of 2-aminobenzothiazole-6-nitro is a unitary product. Separating isomers of sulphonated acids in the blend is an expensive technological operation, maybe even impossible; therefore, biocides in the form of isomers blends have been used to treat bovine hides.
  
  KEY WORDS: biocide, 2-amino-benzothiazole-6-substituted, sulphonation, bovine hides.
Process Re-engineering: Improved Process Methodologies to Produce Defect Free Footwear Leathers
- Pages 118-126
  Victor John SUNDAR, Chellappa MURALIDHARAN
  - Leather Process Technology Department, Central Leather Research Institute, Adyar, Chennai - 600 020, India, +91 44 24911386, email: johnsundar70@yahoo.co.uk
  ABSTRACT. Grain cracking or bursting of footwear upper leathers is a problem encountered by footwear manufacturers very often. Inadequate fiber opening, excessive loading of grain layer of the leathers and improper use and distribution of lubricants have been identified as possible causes for the problem. In order to offset this problem three different approaches have been made: use of Proteolytic enzymes in post tanning, use of poly ethylene glycol along with lubricants and replacement of conventional filling replacement synthetic tanning agents with lubricating syntans. The study has shown that substantial improvement in strength characteristics and organoleptic properties of footwear leathers can be obtained by adopting the above suggested approaches either individually or in combination. Adoption of these would facilitate production of defect free footwear leathers particularly overcoming grain strength related issues of upper leathers.
  
  KEY WORDS: Leather, Footwear, poly ethylene glycol, lubricating syntan and Proteolytic enzyme