Leather and Footwear Journal

Volume 11, no 1

Contents
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Performance of Needles on Sewability of Garment Leathers
- Pages 3-10
  Kavati PHEBE AARON*, Bangaru CHANDRASEKARAN
  - Central Leather Research Institute, Chennai, India, email: kphebejohn@yahoo.co.in
  ABSTRACT. The present study provides scientific knowledge related to the strength and other performance factors of the types of needle points. The combination of material, needle point and thread is what produces a good seam. Garment leathers (goat leathers) were subjected to strength tests using Universal testing machine. Results obtained clearly indicate that diameter, size of needles and type of needle points play crucial role in the strength of leathers subjected to stitching.
  
  KEY WORDS: sewing needle, needle size, needle point, goat nappa, breaking strength
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The Stability of Some Collagen Hydrogels
- Pages 11-20
  Madalina Georgiana ALBU¹*, Irina TITORENCU^2,3, Ciprian CHELARU¹
  - ¹INCDTP Division: Leather and Footwear Research Institute, 93 Ion Minulescu St., 031215, Bucharest, Romania, email: albu_mada@yahoo.com
  - ²Petru Poni Institute of Macromolecular Chemistry, Iasi, Romania, email: firina@yahoo.com
  - ³Nicolae Simionescu Institute of Cellular Biology and Pathology, Bucharest, Romania, email: firina@yahoo.com
  ABSTRACT. Hydrogel dressings are cross-linked polymer gels that are often shaped into sheets to provide and maintain a moist environment on site of wound application. Biological hydrogels are widely used as cell-culture substrates because of their resemblance to the natural extracellular matrix and complex signaling which facilitate the adhesion and growth of cells. In this study the collagen gels were cross-linked with glutaraldehyde in order to obtain a stable structure without any cytotoxic effects. The obtained hydrogels were characterized by thermal analysis, FT-IR spectroscopy, as well as enzymatic degradation and their biocompatibility with endothelial cells was monitored by optic and fluorescence microscopy. The hydrogels cross-linked with 0.4-1.0% did not show any cytotoxic effect in contact with endothelial cells. The hydrogel with 1.2% collagen and 0.8% GA is the most stable and could be a basic promising biomaterial for tissue engineering and drug delivery systems.
  
  KEY WORDS: hydrogels, collagen, biodegradation, endothelial cells
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New Antifelting-Antistatic Treatments of Keratinous Substrates
- Pages 21-32
  Tudorel BALAU MINDRU¹*, Viorica DESELNICU², Olga NICULESCU², Melinda PRUNEANU¹
  - ¹Gheorghe Asachi Technical University of Iasi, 67 Dimitrie Mangeron Blvd., 700050, Iasi, Romania, email: tbalau@ch.tuiasi.ro
  - ² Research and Development Institute for Textiles and Leather, Division: Leather and Footwear Research Institute, 93 Ion Minulescu St., 031215, Bucharest, Romania, email: icpi@icpi.ro
  ABSTRACT. This paper presents a study on the antifelting and antistatic characteristics of keratinous substrates of the natural sheep fur, as a result of treatments applied to these materials. SEM imaging, electrostatic charge measurements performed using a FM 300 fieldmeter and the surface resistivity measured using a Keitley 6517A electrometer, obtained for the three experimental variants compared with untreated control sample, show the advantage of using the new treatment, using a mixture with synergistic effect.
  
  KEY WORDS: sheep furs, antifelting, antistatisation, lubricating, resistivity, electrostatic charge
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Biodegradable Materials Some Untold Tales of Fiction and Consumer High Expectations!
- Pages 33-42
  Ioannis IOANNIDIS*
  - Me-Med Consultants for Leather Industry, 23 Aristodimou St, Athens, Greece, email: ioannidisioa@gmail.com
  ABSTRACT. Sustainability and «green chemistry» are the modern Industry principal drivers at a global scale for new products generation, created with the incorporation from their conception of a «cradle-to-cradle» life cycle approach and eco-design - as «grave» and «burial» can no longer be considered a viable or rational approach to waste management. In response to this emerging market need the term or label «biodegradable», as demonstrated here with real examples, has often been misused by small companies and reputable brand names alike for leathers and leather products in an attempt to promote product eco-friendliness. Degradability testing, as hitherto applied for leathers and leather articles, is critically reviewed and abandoning of the term biodegradable is proposed as an inaccurate claim, seldom tested with any reliability and often misleading the consumer; this, in turn, ought to be substituted by product lifecycle metrics of: (i) Biobased content (ii) «Cradle-to-cradle» Life-Cycle-impact for the product and its specific uses, that, however, is only possible if the primary product is fully retraceable a target far from being realistic at the moment for the leather supply chain - and (iii) Durability and serviceability, as per Eco-index internal benchmarking tool guidelines.
  
  KEY WORDS: leather, biodegradability, compostability, eco, life cycle, bioplastics
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Characteristics of Natural Rubber Blends Vulcanized with Electron Beam and Microwave
- Pages 43-52
  Elena MANAILA¹*, Maria Daniela STELESCU², Gabriela CRACIUN¹
  - ¹National Institute for Laser, Plasma and Radiation Physics, Electron Accelerators Laboratory, 409 Atomistilor St., 077125 Magurele, Romania, email: elenam_inflpr@yahoo.com
  - ²National Research and Development Institute for Textile and Leather Leather and Footwear Research Institute, 93 Ion Minulescu St., Bucharest, Romania, email: dmstelescu@yahoo.com
  ABSTRACT. This paper presents the effect of the polyfunctional monomers (PFMs) triallyl cyanurate (TAC), triallyl isocyanurate (TAIC), trimethylopropane trimethacrylate (TMPT) and zinc diacrylate (ZDA) on the mechanical properties of the NR (natural) rubber crosslinked by electron beam (EB) and microwave processing. The control samples were obtained by crosslinking with benzoyl peroxide in a hydraulic press at 160°C. The most effective polyfunctional monomer which led to getting the best properties was TMPT followed by ZDA. The results indicate that the application of new technologies will lead to a significant improvement in physical and mechanical properties of finished products and to optimizing the curing stage, the most important operation of the technological process for obtaining elastomeric materials.
  
  KEY WORDS: natural rubber, cross-linking, electron beam, microwave, polyfunctional monomers
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The Influence of Surfactants on Separation Processes Involving Membranes
- Pages 53-60
  Demetra SIMION¹*, Olga NICULESCU¹, Carmen GAIDAU¹, Marius SIMION², Georgeta POPESCU³, Ciprian CHELARU¹
  - ¹INCDTP Division: Leather and Footwear Research Institute, Bucharest, 93 Ion Minulescu St., postal code: 031215, Bucharest, Romania, email: demetra.simion@yahoo.com
  - ²INCD ECOIND Bucharest, 90-92 Sos Panduri, Sector 5, email: ecoind@incdecoind.ro
  - ³SC.CCMMM.SA, Research Center for Macromolecular Materials and Membranes, Spl. Independentei 206, 79611, Bucharest
  ABSTRACT. The influence of surfactants upon the wettability of some hydrophobic microporous membranes of polysulphone was studied by determining the contact angle and the ultrafiltration rates. The water-membrane contact angle increases with roughness and changes in presence of the surfactant in aqueous solution to an extent which depends on its nature and concentration. The variations of contact angle of surfactant in aqueous solution are in good agreement with the variation of the rate of ultrafiltration solutions through membranes and with the adsorption of surfactants on polysulphone surface. The method of measuring the contact angle is simple and rapid; it may be employed in characterization of polysulphone membrane, hydrophobicity in spite of the scattering of values obtained of microporous surfaces.
  
  KEY WORDS: surfactants, wettability, ultrafiltration, polysulphone membranes, hydrophobicity
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