Leather and Footwear Journal

Volume 10, no 3

Contents
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The Effects of Different Tanning Agents on Some Properties of Medical Sheepskins
- Pages 3-12
  Behzat Oral BITLISLI*, Huseyin Ata KARAVANA, Bahri BASARAN, Nuray Olcay ISIK
  - Ege University, Engineering Faculty, Leather Engineering Department, 35100, Bornova-Izmir/Turkey, e-mail: oral.bitlisli@ege.edu.tr
  ABSTRACT. In this research washing and perspiration fastnesses of medical sheepskins produced with different combinations of aluminium triformate, basic chromium sulphate, polyaldehyde, synthetic and vegetal tanning agents were investigated. It was found that differences of the softness values between the process recipes were statistically significant (P<0.05). It was determined that softness characteristics of leathers after washing and perspiration treatment had improved depending on usage rate of chromium and polyaldehyde. It was also detected that lighter leathers could be produced by using more chromium and area loss of leathers after washing and perspiration treatment was minimum level by increasing usage rate of polyaldehyde. Differences of the colour coordinate values between the procedures were found statistically significant (P<0.05). It was determined that colour characteristics of leathers changed depending on tanning agents and leathers are lighter when the ratio of aluminium increases.
  
  KEY WORDS: medical sheepskin, perspiration fastness, washing fastness
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The Influence of Some Technological Parameters on the Pickling of Sheepskins Using Dicarboxylic Acids
- Pages 13-24
  Stelian Sergiu MAIER¹*, Viorica DESELNICU², Vasilica MAIER¹, Olga NICULESCU²
  - ¹Gheorghe Asachi Technical University of Iaşi, 67 Dimitrie Mangeron Blvd., 700050, Iaşi, Romania, email: smaier@ch.tuiasi.ro
  - ²National R&D Institute for Textile and Leather - Division: Leather and Footwear Research Institute, 93 Ion Minulescu str., 031215, Bucharest, Romania, email: icpi@icpi.ro
  ABSTRACT. The paper presents a study on the ability of a mixture of dicarboxylic acids to induce pickling effects on sheepskins. The mixture comprising 60% glutaric acid, 20% adipic acid and 20% succinic acid may decrease the shrinkage temperature of the dermis with 20 to 25°C (from approximately 61°C to about 37°C), when 2 to 4 g/L are used. Based on polynomial models developed starting from a complete factorial experiment 23, the influential factors are discussed, and the correlations between factors are highlighted.
  
  KEY WORDS: sheep pelts, pickling, dicarboxylic acids
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Diversification of Footwear through Development of the Shoe Uppers
- Pages 25-38
  Florentina HARNAGEA¹*, Marta Catalina HARNAGEA²
  - ¹Faculty of Textiles-Leather and Industrial Management, Iasi, harnagea@tex.tuiasi.ro
  - ²Faculty of Textiles-Leather and Industrial Management, Iasi, charnagea@tex.tuiasi.ro
  ABSTRACT. The footwear diversification is necessary for assuring competitive products and it can be obtained through applying some development criteria. Thus the paper presents the research results on the product diversification through developing the base pattern of the shoe upper. Starting with a women's court shoe, vamp and quarters have been developed for diversification through changing their configuration and shape. For group models (12 constructive model types), the configuration of patterns and the set size has a significant influence on the mean nesting factor and on the normal wastes. The analysis of the model types has highlighted the influence of patterns number on the wastes size (Dn, Dm+t, Dp) and on the utilization index of the leather surface at cutting the patterns and calculating the specific consumption.
  
  KEY WORDS: development, footwear, nesting factor, wastes, utilization index, specific consumption
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Preparation and Characterization of Collagen Matrices Obtained at Different Freezing Temperatures
- Pages 39-50
  Madalina Georgiana ALBU¹*, Anton FICAI², Adriana LUNGU³
  - ¹INCDTP - Division: Leather and Footwear Research Institute, 93 Ion Minulescu, 031215, Bucharest, Romania, albu_mada@yahoo.com
  - ²University Politehnica of Bucharest, 313 Spl. Independentei, Bucharest, Romania, anton_ficai81@yahoo.com
  - ³University Politehnica of Bucharest, Department of Polymer Science and Technology, 149 Calea Victoriei, Bucharest, Romania, adriana_lungu2006@yahoo.com
  ABSTRACT. Porous collagen matrices with defined physical, chemical and biological characteristics are interesting materials for tissue engineering and drug delivery systems. In this study type I collagen gels were cross-linked with glutaraldehyde and then dried using different freezing temperatures during the lyophilization process. The obtained matrices were analyzed by DSC, TGA/DTG, FT-IR and SEM.
  The results show that triple helical structure of collagen is preserved during the lyophilization process and the pore sizes of collagen structure depend on the freezing temperature.
  
  KEY WORDS: collagen, freeze-drying, biomaterial, porosity
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Characteristics of Silicone Rubber Blends
- Pages 51-58
  Maria Daniela STELESCU*
  - National Research and Development Institute for Textile and Leather - Leather and Footwear Research Institute, 93 Ion Minulescu St., Bucharest, Romania, dmstelescu@yahoo.com
  ABSTRACT. In this paper, characteristics of silicone rubber blends cross-linked with various cross-linking systems based on benzoyl peroxide and benzoyl peroxide in the presence of the triallylcyanurate (TAC) coagent were analyzed. For analyzed samples, physical-mechanical properties, rheologic characteristics, gel fraction and cross-link density were determined.
  
  KEY WORDS: silicone rubber, cross-linking, peroxide, triallylcyanurate
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Influence of Various Types of Reinforcing Agents on Polymer Structures Based on Butadiene-Co-Acrylonitrile Rubber
- Pages 59-66
  Maria FICAI¹*, Ana STAN², Adriana STEFAN², Mihai GEORGESCU¹, Mihaela VILSAN¹
  - ¹National Research and Development Institute for Textiles and Leather - Division: Leather and Footwear Research Institute, 93 Ion Minulescu St., Bucharest, Romania, icpi@icpi.ro
  - ²National Institute of Aerospace Research Elie Carafoli, 220 Iuliu Maniu Blvd., Bucharest, Romania, anastan@incas.ro
  ABSTRACT. In this paper a multitude of polymer blends on a Brabender laboratory roll in the presence of many auxiliary materials with well-determined role in influencing the properties of the finished product. Upon the analysis of physical-mechanical values, it can be noticed that the density of polymer structures increases proportionally with filler quantity, while properties such as elasticity decrease proportionally with it. Due to the fact that butadiene-co-acrylonitrile rubber is not crystallized by stretching, in the absence of reinforcing agents, it often has unsatisfactory physical-mechanical properties. In the presence of active reinforcing agents of nano sizes, due to the large specific surface, the interactions developed between elastomer and reinforcing agents are maximized leading to compatibilization. Based on results obtained from experiments, it can be stated that polymer structures based on butadiene-co-acrylonitrile rubber are resistant to immersion in isooctane, in strong acids and bases, in mineral oils and organic plasticizers. The obtained blends have optimal characteristics for use in the field of vulcanized footwear for general use, in the food industry, for gaskets, and due to their resistance to immersion in isooctane, acids and bases, they can be used in aggressive environments.
  
  KEY WORDS: reinforcing agents, hardness, butadiene-co-acrylonitrile rubber
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