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Improvements in Leather Surface Hydrophobicity through Low-pressure Cold Plasma Polymerization 
by Ya-e Feng, Xuepin Liao, Yanan Wang and Bi Shi
Volume: 109      Number: 3     Page: 89-95     Year: 2014
Vinyltriethoxysilane (VTES) was polymerized and deposited on the surface of upholstery crust leather by using low-pressure cold plasma technology. After plasma treatment (50 W, 300 s), the initial water contact angle of the leather surface increased from 120o to 140o, showing a significantly improved hydrophobicity of leather surface. The increased hydrophobicity of leather surface could remained even the leathers were stored for 240 d. The surface morphologies of leather were characterized by Scanning Probe Microscope (SPM) and Scanning Electron Microscope (SEM). Unlike the fiber-like texture of untreated leather, a coating of VTES polymer on the plasma treated leather surface was observed by SPM. SEM and SPM images indicated that this coating film was on the surface of collagen fibers rather than the whole surface of leather, which would not reduce permeability of air and water vapor of the leather. Energy Dispersive X-ray Spectroscopy (EDS) was performed to determine the chemical composition of leather surface. The contents of Si and O increased remarkably as leather surface was covered with polymerized VTES. The X-ray Photoelectron Spectroscopy (XPS) showed that the peaks attributed to C=C bonds of VTES and C=O bonds of collagen disappeared after plasma polymerization. All these results demonstrated that VTES was polymerized and deposited on the surface of collagen fibers after plasma treatment, which resulted in a hydrophobic surface of leather.
 
 
Biopolymers Produced from Gelatin and Whey Protein Concentrate Using Polyphenols 
by M. Taylor, J. Lee, L. Bumanlag, R. Latona and E. Brown
Volume: 109      Number: 3     Page: 82-88     Year: 2014
Several researchers have recently demonstrated the feasibility of producing biopolymers from the reaction of polyphenols with gelatin in combination with other proteins (e.g. whey) or with carbohydrates (e.g. chitosan and pectin). These combinations would take advantage of the unique properties of both species and at the same time create products with enhanced functional properties. We have successfully demonstrated that the polyphenolic gallic acid and the vegetable tannins quebracho and tara could be used to modify gelatin and whey protein concentrate (WPC) resulting in a subsequent change in the physicochemical properties of each. When gelatin-polyphenol products were used as fillers, considerable improvements were seen in the subjective properties of the leather and when compared to control samples, there was no significant impact on mechanical properties. In this continuing research, we have begun to evaluate the potential of tara-modified gelatin/WPC biopolymers, specifically for their application as fillers. In this study, modification parameters for gelatin/WPC combinations will be explored, and the results of product characterization using physicochemical analyses will be presented. These studies could further contribute the use of sustainable resources in production of unique products that may have leather processing applications.
 
 
Studies on Ethiopian Sheep Skins as an Opportunity for Value Addition Part I: Histological, Microscopic and Chemical Characterization of Abyssinian and Wanke Sheepskins 
by H. Mohammed, G. Aysanew, R. Aravindhan, A. Gnanamani, J. Rao and N. Chandrababu
Volume: 109      Number: 3     Page: 76-81     Year: 2014
The leather industry is one of the priority sectors in Ethiopia, which has been identified as potentially competitive in the global market. Ethiopian tanners face a shortage of raw material input for production of leather. The government strategically planned for importing raw skins from neighboring countries and also for effective utilization of available raw material resources in the country. About fourteen sheep breeds are recognized in Ethiopia. Among the available resources, Wanke sheepskins, indigenous to lowland of Ogaden area of Somali Region take prime position based on their availability. Meat of Wanke sheep is in high demand in international market, but the skin commands low price not only due to availability but also less demanded by tanners due to natural problems associated with the skin. In this paper the histological, chemical and physical characteristics of Wanke sheepskins have been analyzed using various tools and techniques. This characteristic understanding of the Wanke sheepskins will enable the development of process strategy to produce Wanke leathers with improved properties.
 
 
Effects of Thickness and Gain on the Amplitude of Airborne Ultrasonics 
by C.K. Liu and N. Latona
Volume: 109      Number: 3     Page: 70-75     Year: 2014
Currently, hides and leather are visually inspected and graded for quality, usable area, and sale price. However, visual inspection is not reliable for detecting defects that are hidden inside the material. Development of a non-contact nondestructive method to accurately evaluate the quality of hides and leather is urgently needed. We previously reported the research results for airborne ultrasonic (AU) testing using non-contact transducers to evaluate the quality of hides and leather. The ability of AU testing was demonstrated for revealing defects in hides and leather that were difficult to be found during visual inspection. We also reported results on AU inspection using a statistical data/cluster analysis technique, in which leather and hide defects were depicted as color-coded amplitude maps, or C-scans. Recently new research was carried out to study the effects of transducer frequency, thickness of leather, and AU gain on the resultant AU amplitude received, which was shown in a C-scan imagine. Observation showed that a lower frequency of 100 KHz yielded better transmission of AU waves through samples and the AU gain should be less than -5dB. In addition, the amplitude of the C-scan decreased with the thickness of the samples. This study has provided a significant guidance for successful AU testing.
 
 
Flocculation Behaviors of Collagen Protein-Al(III) Composite Flocculant 
by Ruiqin Li, Jianfei Zhou, Xuepin Liao, Wenhua Zhang and Bi Shi
Volume: 109      Number: 2     Page: 56-62     Year: 2014
Hydrolyzed collagen protein (HCP) was prepared by the hydrolysis of solid skin wastes, and then cross-linked with glycerol triglycidyl ether (GTE) to produce cross-linked collagen protein (CCP). By combination CCP with different amounts of Al2(SO4)3, a series of CCP-Al (III) composite flocculants (CCP-Al) were successfully synthesized. A kaolin suspension (5 g/L) was utilized as a model system to investigate the flocculation behaviors of the as-prepared flocculants. When the dosage of the CCP-Al was 50 mg/L, the flocculation extent reached 95% in 20 minutes with the sludge volume ratio lower than 15%. Under the same conditions, the CCP-Al exhibited better flocculation performance than the Al2(SO4)3. Scanning electron microscope (SEM) observations revealed that the size of flocs formed by CCP-Al was larger than that of Al2(SO4)3, suggesting a better aggregation of flocs.
 
 
Extraction of Keratin from Unhairing Wastes of Goatskin and Creating New Emulsion Formulation Containing Keratin and Calendula Flower (Calendula officinalis L.) 
by E. Bayramoglu, A. Yorgancioglu, G. Yeldiyar and E. Onem
Volume: 109      Number: 2     Page: 49-55     Year: 2014
This study demonstrates the use of keratin extracted from unhairing wastes of goatskin for cosmetics. Keratin has been purified from unhairing wastes of goatskin according to the oxidation method for producing emulsions. The experimental process to prepare the emulsions includes Oil/Water (O/W) emulsion method with keratin and Calendula officinalis flower extract (Calendula officinalis L.). Four emulsion creams with different ratios of keratin and calendula ingredients were formulated. Fourier transform infrared spectroscopy (FTIR) analysis of the keratin purified and pH, viscosity and average particle size analyses of the emulsions prepared have been carried out. The results of the study have shown that keratin obtained from unhairing wastes of leather industry could be smoothly used in producing emulsion formulations with calendula flower ingredient.
 
 
Associated Use of Enzymes and Hydrogen Peroxide for Cowhide Hair Removal 
by E. Andrioli and M. Gutterres
Volume: 109      Number: 2     Page: 41-48     Year: 2014
This study evaluated the use of enzymatic extract produced by a strain of Bacillus subtilis in combination with hydrogen peroxide for hair removal of cowhides. Were tested two concentrations of enzymatic extract (100 and 300 U g-1 of hide), and two concentrations of hydrogen peroxide (4% and 8%). The hides were evaluated visually, and wastewater was evaluated through analysis of total nitrogen, total, fixed and volatile dissolved solids, glycosaminoglycans, proteoglycans and hydroxyproline. The oxidative-enzymatic unhairing didnt cause destruction of hair and reduced the process time compared to the conventional and the enzymatic unhairing. The results showed that the oxidative-enzymatic unhairing can be a viable alternative to the use of lime and sodium sulfide on hair removal.
 
 
Preparation of Nonwoven and Green Composites from Collagen Fibrous Networks 
by C.K. Liu, N. Latona and M. Taylor
Volume: 109      Number: 2     Page: 35-40     Year: 2014
The disposal of solid wastes, such as trimmings and splits generated in various manufacturing processes in a tannery is a serious challenge to the hides and leather industries. Most of these wastes are transported out of processing plants for landfills, not only incurring the expense of transportation, but also creating environmental issues. Our effort to address these new challenges is to develop new uses and novel biobased products from solid wastes to improve prospective markets for the hides and leather industries. We hypothesize collagen fiber networks derived from solid fibrous wastes can be utilized to prepare high performance green composites and air filters, of which both have a great market potential. Collagen fiber networks were obtained from split hides that have been processed to remove the noncollagenous materials through the hair removal, liming, and bating steps. Earlier studies were devoted to understand the effects of dehydration on the resultant fiber networks and the effects of processing steps such as bating, pickling and crosslinking treatments on the morphology and physical properties of the fiber networks derived from un-tanned hides, which will be the starting material for constructing air filters and green composites. This study focuses on preparations of nonwoven and green composites derived from fiber networks. Non-woven sheets were prepared using paper-making technology. They were then used as reinforced components to make composites that use gelatin as the matrix. Mechanical properties were evaluated for the resultant composites; results showed that the fiber sizes and gelatin content have significant effects on the properties of the resultant nonwoven and composites.
 
 
Powdered Hide Model for Vegetable Tanning 
by E. Brown, R. Latona, M. Taylor and A. Gehring
Volume: 109      Number: 1     Page: 8-13     Year: 2014
To demonstrate the utility of the powdered hide model for vegetable tanning studies, interactions of quebracho with samples of powdered hide prepared from partially processed hides were investigated. Hides were dehaired by a typical sulfide or oxidative method and carried through the delime/bate step of a tanning process. Prior to tanning, the powdered hide from oxidative dehairing was on average slightly more susceptible to attack by collagenase than was the powdered hide from sulfide dehairing. After tanning with as little as 20% quebracho, powdered hide from both processes was well protected against collagenase degradation. Apparent shrinkage temperatures ranged between 79C and 87C, increasing with increased quebracho offer. Shrinkage temperatures for quebracho-treated oxidatively powdered hides were generally 2C lower than for sulfide dehaired samples. This contrasts with no difference in shrinkage temperature for chrome tanned powdered hides. Comparison of micrographs of powdered hide treated with crude and purified quebracho suggest that the tanning effect of quebracho is both a function of quebracho/collagen interactions, and the filling effect of other components of the crude quebracho.
 
 
Low Carbon Products to Design Innovative Leather Processes. Part II: Determination of the Optimal Physical Modification of Tara  
by L. Olle, C. Casas, J. Diaz, S. Sorolla and A. Bacardit
Volume: 109      Number: 1     Page: 25-31     Year: 2014
This study considers the fruit of the tara bush as a sustainable source for tanning agents and proposes alternatives to chromium and other mineral salts and vegetable extracts. Specifically, physical modifications have been developed in part II of the study to obtain a modified tara with a higher percentage of tannins and with a better level of penetration (see Low carbon products to design innovative leather processes. Part I: determination of the optimal chemical modification of tara).1 The physical modification of tara focused on milling and sieving. The different products obtained have been characterized and applied to leather samples in order to evaluate the degree of penetration and stabilization in the leather structure.