Application of green cationic silicon-based gemini surfactants to improve antifungal properties, fibre dispersion and dye absorption of sheepskin

by Yan Bao; Yuanxia Zhang; Jiajia Guo; Jianzhong Ma; Yuyao Lu

In view of conventional surfactants, cationic silicon-based gemini surfactants possess three more advantages imparted by unique structure. Therefore, in this paper, a series of green cationic silicon-based gemini surfactants (CmePSieCm) with different hydrophobic chain length (m ¼ 8, 12, 18) were used in sheepskin soaking and dyeing processes firstly. Then the properties of sheepskin after CmePSieCm treatment were studied and their waste bath was analyzed. Meanwhile, traditional soaking scheme (JFC and commercial fungicide) and commercial dye-fixing agent as comparisons were also used in sheepskin soaking and dyeing processes, respectively. The results showed that all performance of sheepskin after C12ePSieC12 treatment was the most outstanding. Antifungal properties and fiber dispersion of sheepskin after C12ePSieC12 treatment were almost similar to or even better than traditional soaking scheme. C12ePSieC12 was conductive to remove the interfibrillary protein among the collagen fibres, but did less damage to collagen fibre in the soaking process. Most importantly, the dosage of C12ePSieC12 was only half of the traditional soaking scheme, dramatically reducing the use and waste of the resource. Moreover, C12ePSieC12 was beneficial to the absorption and fixation of the dye by sheepskin. Compared with commercial dye-fixing agent, the dye concentration in dyeing waste bath using C12ePSieC12 decreased notablely from 3.13 mg/L to 1.75 mg/L. So C12ePSieC12 can replace traditional soaking scheme and commercial dye-fixing agent using in leather soaking and dyeing processes. In short, C12PSieC12 as a kind of eco-friendly substance has been presented, which can improve antifungal properties, fiber dispersion and dye absorption of sheepskin synchronously, and can reduce environmental pollution and provide the way for sustainable development of cleaner leather processing.

Journal of cleaner production 2019

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 SO2concentration. 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.

JALCA Nov 2018

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.

JALCA Nov 2018

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 CaCO3accelerates 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/CaCO3are most probably described by third (F3) and second (F2) order models, respectively. Morphological/elemental analysis showed calcium dispersed evenly over the VCF/CaCO3.

JALCA Nov 2018

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.

JALCA Nov 2018

An environmental polyurethane retanning agent with the function of reducing free formaldehyde in leather

by Xuechuan Wang; Zhuan Yan; Xinhua Liu; Taotao Qiang; Liang Chen; Peiying Guo; Ouyang Yue

Chromotropic Acid Grafted Amphoteric Polyurethane (CAGAPU) was synthesized with Chromotropic Acid (CA) as a modifier for Polyurethane (PU). The structure of CAGAPU was confirmed by FT-IR, 1 H-NMR. The retanning process and the experiments of CAGAPU with formaldehyde indicate the following: (1) The leather retanned by CAGAPU can be comparable or surpassed to the market PU-based retanning system in terms of shrinkage temperature and sensory performance. (2) The leather collagen fibers are smoother and orderly which provides a potential value for the appearance of the leather and fur industry. (3) The CAGAPU retanned system can bring down the free formaldehyde content in aldehyde tanned leather significantly. (4) The optimum dosage of CAGAPU is 20 g and the best retanning time is 6 h (5) The CAGAPU retanned system can reduce the free formaldehyde, Biochemical Oxygen Demand (BOD), Total Dissolved Solids (TDS) and Total Suspended Solid (TSS) from the source which retard pound on the economy and environment greatly compare to the traditional governance. Therefore, this paper provides the possibility for the sustainable development of leather. The work has changed the traditional way of “terminal treatment” and realized the “initial treatment” and may also offer a new idea of solving the problem of formaldehyde in the newly decorated houses or in the air.

Journal of cleaner production, 2019

Nanostructure of electrospun collagen: Do electrospun collagen fibres form native structures?

by Sizeland, K.H.; Hofman, K.A.; Hallett, I.C.; Martin, D.E.; Potgieter, J.; Kirby, N.M.; Hawley, A.; Mudie, S.T.; Ryan, T.M.; Haverkamp, R.G.; Cumming, M.H.

Collagen extracts can be electrospun to form fibres. The nanoscale structure of these fibres is not known but is expected to affect the biocompatibility of the spun materials. Collagen extracts from Macruronus novaezelandiae (hoki) skin were electrospun to form a fibrous material. The structure of the electrospun collagen fibres was analyzed and compared with the structure of native collagen, gelatin, and electrospun gelatin. Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) and SDS-PAGE were used to characterize the basic molecular structure of the biomaterials and synchrotron-based small-angle X-ray scattering (SAXS) and Transmission electron microscope (TEM) were used to investigate the fibril nanoscale structure (molecular arrangement). ATR-FTIR and SDS-PAGE revealed characteristic patterns of intact alpha chains in the electrospun collagen and hydrolyzed fragments in electrospun gelatin, as expected. TEM revealed fibres in both the native collagen material and the electrospun samples. However, SAXS patterns showed axial periodicity was not present in the electrospun fibers. This is indicative of the spinning process forming fibers that lack internal fibril structure, in contrast to the hierarchical structure of native collagen. The architecture of collagen affects its function. By characterizing the molecular and fibril structure of electrospun collagen and comparing it with native collagen fibrils, we may inform functional studies of collagen, including its configuration for cell attachment and recognition.

Materialia Oct 2018

The technology and application of 3D scanning

by Mason, Harriet

How 3D scanning works and its value to footwear producers.

Interest in three-dimensional (3D) scanning technologies has grown over the last few years. This is due in part to advances in technology that have allowed scanners to become smaller, more portable and more powerful, as well as the increasing range of different applications envisaged across multiple industries.

Most 3D scanners are laser-based and use a process called ‘trigonometric’ triangulation. This involves two or more lasers being shone at a point on an object, after which the angles of the reflected beams are recorded by one or more sensors (figure 1). When repeated across millions of points, the distances between the scanner and these points on the object and the directions of the beams as they bounce back build up into a 3D map of the surface of a scanned object. Once the 3D scan is complete, it can be assessed and measurements such as distance, volume area and angle can be taken from it.

SATAR Bulletin Oct 2018