November 2018 Abstracts

An Experimental Comparative Study of the Effect of Skin Type on the Stability of Vegetable Leather Under Acidic Condition

by Alireza Koochakzaei, Hossein Ahmadi and Shadpour Mallakpour

Vegetable tanned leather is very sensitive to environmental factors, especially acidic pollutants. In addition to environmental factors, the type of animal and tannin consumed highly influences the structure and deterioration of leather. Therefore, this comparative study aimed at evaluating the stability of sheep and goat leather, tanned with mimosa extract, during the accelerated aging process. The leathers were submitted to accelerated aging for two weeks at 40°C, 50% RH and 100 ppm SO2 concentration. The attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, colorimetry, fiber-optics reflectance spectroscopy (FORS), pH measurements, investigation of mechanical properties and shrinkage temperature (Ts) were used to investigate influence of the accelerated aging condition on physical and chemical properties of leather. Results showed that sheep leather has better structural stability against acidic deterioration with compared to goat leather. While, goat leather showed higher color stability than sheep leather. Moreover, results revealed that deterioration level in grain layer was more severe than corium.

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Natural Fibers Reinforced Chrome Shaving Composites for Sound Absorption Applications

by D. Hemalatha, S. Kowsalya, N. Nishad Fathima, S. Sowmya and J. Raghava Rao

Chrome shavings, the solid wastes from tanneries, show disposal difficulties due to the presence of the heavy metal chromium. In this present study, we have prepared sound absorbing materials from chrome shavings by blending with suitable synthetic and natural polymers via compression molding technique. Polypropylene (PP), was chosen as a synthetic polymer to improve the blending and natural fibers such as cotton, jute and kapok have been chosen for their porous nature. The composites were prepared, and their morphology was examined using scanning electron microscopy. The sound absorption of the prepared composites has been measured using Impedance tube method. The results suggest that composites blended with polypropylene exhibit more than 90% sound absorption in the mid frequency range. This study shows that chrome shavings in combination with natural fibers can be used as good sound absorption materials. Thus, the proposed approach paves the way for utilization of a leather waste to reduce noise pollution.

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Thermal Stability and Degradation Kinetics of Vegetable-tanned Collagen Fiber with in-situ Precipitated Calcium Carbonate

by Jie Liu, Eleanor M. Brown, Joseph Uknalis, Cheng-Kung Liu, Lan Luo and Ke-Yong Tang

The effects of in-situ precipitated calcium carbonate (CaCO3) on the thermal stability and decomposition kinetics of vegetable-tanned collagen fiber (VCF) are evaluated by thermogravimetry. The kinetic and mechanism analysis of the decomposition stage use an integrated procedure involving model-free methods and master-plots method. Various methods are employed to calculate the activation energy of the fibers. It is shown that VCF/CaCO3 exhibits better thermal stability than VCF in the range 22-350°C. However, thermogravimetric results also show that the presence of CaCO3 accelerates the decomposition process at higher temperatures. When the conversion values are below 0.4, the most probable decomposition mechanism for VCF and VCF/CaCO3 is random nucleation and nuclei growth (Avrami, equation A2). Above 0.4, the decomposition mechanisms of VCF and VCF/CaCO3 are most probably described by third (F3) and second (F2) order models, respectively. Morphological/elemental analysis showed calcium dispersed evenly over the VCF/CaCO3.

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Synergy of Organic Nanoclay and Inorganic Phosphates for Fire Retardant Leather Applications

by Jima Demisie Wegene and Palanisamy Thanikaivelan

Leather is a material used for various purposes including upholstery in airplanes, ships, automobiles and furniture. Leather requires good fire resistance properties for use in upholstery due to the possibilities of exposure to fire. Here, we report a method to produce fire retardant leather using organic nanoclay and ammonium dihydrogen phosphate as flame retardant additives through surface coating. Treated leathers were characterized using vertical flammability test, thermogravimetric analysis, scanning electron microscopic analysis, mechanical and hand and visual evaluation. Treated leathers left higher residues at 700oC than the control leather indicating their lower thermal decomposition potential. Further, we demonstrated that the ignition time of treated leathers is increased by more than 5 sec and treated leathers show negligible flame time after fire source was removed. The physical and organoleptic evaluations of treated leathers as well as other results suggest that a combination of organic nanoclay and inorganic phosphate provides fire retardant leathers for upholstery leather applications with acceptable strength and bulk properties.

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