Leather and Footwear Journal

Volume 13, no 1

Contents
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Effect of Gallic Acid Content on Tannin-Titanium (III) Combination Tanning
- Pages 3-12
  Bo TENG^1,2, Xiaoyun JIAN^1,2, Wuyong CHEN^1,2*
  - ¹Key Laboratory for Leather Chemistry Engineering of the Education Ministry, Sichuan University, 610065, Chengdu, China
  - ²National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, 610065, Chengdu, China, email: wuyong.chen@163.com
  ABSTRACT. The combination tanning using titanium (III) and hydrolysable tannin extracts was reported as a better tannage to improve the properties of leather than condensed ones. One of the most obvious differences between these tannin extracts was the gallic acid content. To clarify the effect of this reactive structure on tannin-Ti (III) combination tanning, Acacia Mangium tannin extract (no gallic acid), Orange Oil tannin extract (25% gallic acid) and Strawberry Tree tannin extract (40% gallic acid) were selected for tannin-Ti (III) complex and tanning experiments. The quantity of precipitation, pH of complexation system and shrinkage temperature were used as main evaluation factors of this investigation. Under different temperature and pH conditions with different dosages of tannin extracts and Ti (III) agent, their complex ability and tanning ability were studied respectively. The results show that: the gallic acid in tannin extracts could improve its complex ability with Ti (III) under different temperature and pH conditions; the tannin extracts with more gallic acid showed higher effective complexation index, and better reactivity to complex with Ti (III). So, higher thermal stability was obtained with less tanning agent; under tanning condition, the more the gallic acid content in tannin extracts, the higher the thermal stability of leather presented. This research could provide a reference for the Ti (III) - vegetable extracts combination tanning.
  
  KEY WORDS: gallic acid, tannin extract, combination tanning
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The Influence of TMPT Coagent on the Cross-link Density of the EPDM Rubber Vulcanized by Irradiation
- Pages 13-20
  Elena MANAILA
  - National Institute for Laser, Plasma and Radiation Physics, Electron Accelerators Laboratory, #409 Atomistilor St., 077125 Magurele, Romania, email: elenam_inflpr@yahoo.com
  ABSTRACT. This paper presents the effect of the polyfunctional monomer trimethylopropane trimethacrylate (TMPT) on the cross-link density and gel fraction of the ethylene-propylene rubber (EPDM) cross-linked by electron beam (EB) processing. Dependence of gel fraction and crosslink density on irradiation dose was determined from a dose range of 12.5 kGy to 50 kGy.
  
  KEY WORDS: ethylene-propylene terpolymer rubber, cross-linking, electron beam, microwave, trimethylopropane trimethacrylate
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The First Social & Environmental Report of the European Leather Industry
- Pages 21-48
  Federico BRUGNOLI¹, Gustavo GONZALEZ-QUIJANO¹, Luminita ALBU^2*
  - ¹COTANCE, 3 Rue Belliard, B-1040 Brussels, Belgium, email: brugnoli@spin360.biz, cotance@euroleather.com
  - ²INCDTP - Division: Leather and Footwear Research Institute, 93 Ion Minulescu, 031215, Bucharest, Romania, email: luminita.albu@icpi.ro
  ABSTRACT. This first Social & Environmental Report of the European Leather Industry has been elaborated within the context of the SER III Social Dialogue Project, implemented by the social partners of the European Tanning Industry: COTANCE and IndustriAll-European Trade Union. The paper represents a novel approach which takes into consideration the main elements that are linked with the sustainable development and economic growth of European tanneries. Key strategic concepts illustrated in the paper concern the ecological role of tanneries that base their production on by-products of renewable origin. They build their leadership on a mix of tradition and innovation and therefore require a particularly skilled workforce. The paper, moreover, presents in detail the structure of the European sector and, thanks to the contribution of several national industrial associations (representing 90.9% of European tanneries and 76.6% of the workforce), provides key environmental and social indicators linked with the industrial activity. The comprehensive analysis of social and environmental indicators demonstrates that tanneries in Europe are increasingly committed to the ethical and social aspects of their business, and that, through continuous investments, they have been able to ensure substantial improvements in process efficiency and in pollution prevention and control. All the efforts made by European tanneries over the years have resulted in improving the sustainability of their production. The excellent results achieved deserve to be valued more by stakeholders and better incentivised through measures encouraging new and future investments. The environmental and social values demonstrated by European leather help to keep European tanners ahead of international competition.
  
  KEY WORDS: social report, ecological role, sustainable development, leadership, tradition & innovation
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The Mechanical Properties of Ethylene-Vinyl-Acetate Copolymer/Triallylcyanurate Mixture Cross-linked by Electron Beam and Microwave Processing
- Pages 49-60
  Gabriela CRACIUN*, Daniel IGHIGEANU
  - National Institute for Laser, Plasma and Radiation Physics, Electron Accelerators Laboratory, #409 Atomistilor St., 077125 Magurele, Romania, email: gabriela.craciun@inflpr.ro
  ABSTRACT. In this study, the effect of the polyfunctional monomer triallylcyanurate on the mechanical properties of the ethylene-vinyl acetate copolymer cross-linked by electron beam and microwave processing was investigated. The control samples were obtained by crosslinking with dibenzoyl peroxide. The results show an improvement of mechanical properties for samples cross-linked by irradiation.
  
  KEY WORDS: ethylene-vinyl-acetate-copolymer, triallylcyanurate, cross-linking, irradiation
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Influence of Montmorillonite Nanoparticles on Polychloroprene Adhesive Properties
- Pages 61-80
  Laurentia ALEXANDRESCU^1*, Maria FICAI¹, Luminita Florica ALBU¹, Minodora LECA², Marian MIHUT²
  - ¹INCDTP Division: Leather and Footwear Research Institute, 93 Ion Minulescu St., Sect. 3, 031215-Bucharest, Romania, email: icpi@icpi.ro, laura_alexandrescu@yahoo.com
  - ²University of Bucharest, Faculty of Chemistry, Department of Physical Chemistry, 4-12 Regina Elisabeta Blvd., Sect. 3, 030018-Bucharest, Romania, email: minodora.leca@yahoo.com
  ABSTRACT. The aim of this study was to investigate the influence of montmorillonite nanoparticles on polychloroprene adhesive properties. This paper deals with obtaining ecologic adhesive nanodispersions based on chloroprene elastomer grafted with functional chemical groups on the chain of the basic elastomer compounded with Na-montmorillonite (Cloisite Na +). The water dispersing of an elastomer with significant crystallization characteristics (which is specific for the elastomers used as adhesives, as chloroprene rubbers) subjected previously to chemical grafting and dispersion by means of fillers (Na-montmorillonite - Cloisite Na +), dispersing and crosslinking agents will be tested. This way a solution of grafted elastomer in methylene chloride is prepared. To the cold solution a water solution of (anionic or non-ionic) surfactant is added under strong stirring provided by an agitator with high shearing rate. The resulting ecological adhesive nanodispersions were characterized using FTIR, SEM, particle size distribution analysis and peeling resistance. The presence of lateral chains in the grafted elastomer and montmorillonite nanoparticles influence its characteristics. Introduction of graftings and dispersion will be accomplished at a nano scale and using a high accuracy technology in chemistry, namely through forming active sites on the basic elastomer macromolecule, on which reactive groups such as methyl methacrylate will lead to an increase in bonding capacity.
  
  KEY WORDS: montmorillonite, chemically grafted, polychloroprene, nanodispersions, adhesives
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