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Schroepfer M.,FILK Research Institute of Leather and Plastic Sheeting | Schulz H.,FILK Research Institute of Leather and Plastic Sheeting | Czerny M.,German Research Center for Food Chemistry | Czerny M.,Fraunhofer Institute for Process Engineering and Packaging | Schieberle P.,German Research Center for Food Chemistry
32nd Congress of the International Union of Leather Technologists and Chemist Societies, IULTCS 2013 | Year: 2013

One of leather's important characteristic is its smell. In contrast to synthetics the leather smell is desired and regarded as an attribute of authenticity by customers in many countries. For research works 5 different leathers from different application areas were chosen. Depending on manufacturing technology the leathers showed different nuances of leather smell. Presentation gives results from analysis of leathers by GC-O, AEVA, GC-MS and SIVA for identifying and quantifying substances accountable for certain leather smells. Furthermore, it points out from which stages of leather manufacturing the leather smell originates and if it can be influenced. Alternative methods for identification and quantification of substances relevant to smell are discussed regarding their informational value. Source


Kluver E.,FILK Research Institute of Leather and Plastic Sheeting | Meyer M.,FILK Research Institute of Leather and Plastic Sheeting
Journal of Applied Polymer Science | Year: 2013

This article describes a technology for the thermoplastic treatment of collagen. Based on limed, untanned cattle pelts a fine powder, termed Thermoplastic Collagen (TC) is produced, which can be processed using conventional thermoplastic techniques. Central step in the production of TC is the partial denaturation of collagen, which was achieved by four different methods. Extrusion of TC at temperatures below 100°C is possible after addition of 30-60% water as plasticizer. In order to maintain permanent flexibility and reduce tackiness, glycerol and stearic acid are used as additives. Shear and elongational viscosities of TC-water-mixtures decrease with the shear rate which is consistent with the behavior of thermoplastic materials. The power law can be applied, yielding power law indices of 0.15-0.35. The viscosities are more distinctly influenced by raw material and water content than by temperature or glycerol content. Material properties of the extrudates are described and compared with the starting material. © 2012 Wiley Periodicals, Inc. Source


Kluver E.,FILK Research Institute of Leather and Plastic Sheeting | Meyer M.,FILK Research Institute of Leather and Plastic Sheeting
Polymer Engineering and Science | Year: 2015

Plant protein isolates (wheat gluten, soy, and pea protein) were treated in a thermoplastic extrusion process, yielding protein based bioplastic material. The application of glycerol as plasticizer in amounts of 50-67% of total mass and high temperatures above 140°C led to smooth and homogeneous extrudates. Viscosity measurements of the protein melt under extrusion conditions confirmed the thermoplastic behavior, obeying the power law with power law indices of 0.31-0.4. Chemical changes in the material were qualitatively shown by amino acid analysis and fluorescence measurement. High moisture sensitivity and low mechanical stability of the extrudates, as determined by solubility, water vapor permeability, sorption isotherms, and tensile strength, can be partially ascribed to the high glycerol content. The application of pure protein bioplastics for technical purposes, e.g., as packing material, is discussed on basis of the presented data considering stability, appearance, and long time storage. © 2014 Society of Plastics Engineers. Source


Schropfer M.,FILK Research Institute of Leather and Plastic Sheeting | Kluver E.,FILK Research Institute of Leather and Plastic Sheeting | Meyer M.,FILK Research Institute of Leather and Plastic Sheeting
Journal of the American Leather Chemists Association | Year: 2014

The influence of elastin degradation in leather on important mechanical properties was investigated. The elastin content of pelts and wet blues was determined by chromatographic analysis of desmosine, which is a specific and hydrolytically stable crosslinking. Analysis of pelts was performed directly, while chrome containing samples had to be detanned prior to analysis. It is demonstrated that elastase significantly reduces the elastin content. In contrast to often assured statements on the marked influence of elastase on softness, area yield, tensile strength and elongation of leather, our investigations showed no significant changes in the mechanical properties of leather as well as area yield, grain quality or softness after treatment with elastase. It is concluded that the impact of elastin on leather properties is generally lower than postulated before or that it is not pronounced in the dry state. Source

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