title: Looseness in bovine leather: microstructural characterization.
abstract: BACKGROUND
  A substantial proportion of bovine leather production may be of poor quality, with the leather suffering from a characteristic known as looseness. This defect results in a poor visual appearance and greatly reduced value. The structural mechanism of looseness is not well understood.
  
  
  RESULTS
  Samples of loose and tight bovine leather are characterized using small-angle X-ray scattering, ultrasonic imaging, and electron microscopy. The density of fibre packing and orientation of the fibrils are analysed. Tensile strength is also measured. Loose leather is characterized by more highly aligned collagen fibrils. This results in a weaker connection between the layers. There is a looser packing of the fibres in loose leather than in tight leather, with more gaps between fibre bundles, particularly in a region in the lower grain. This region is visible with in situ ultrasonic imaging. Loose leather has a higher tensile strength than tight leather.
  
  
  CONCLUSIONS
  While a high degree of collagen fibril alignment is normally associated with strong leather, it has been shown that too much alignment results in loose leather. Understanding the physical basis of looseness is the first step in identifying looseness in hides and learning how to prevent looseness from developing during leather manufacture. © 2015 Society of Chemical Industry.
authors: School of Engineering and Advanced Technology, Massey University, Private Bag 11222, Palmerston North, New Zealand.
authors: Hannah C
authors: HC
authors: Wells
authors: Leather and Shoe Research Association of New Zealand, PO Box 8094, Palmerston North, New Zealand.
authors: Geoff
authors: G
authors: Holmes
authors: School of Engineering and Advanced Technology, Massey University, Private Bag 11222, Palmerston North, New Zealand.
authors: Richard G
authors: http://orcid.org/0000-0002-3890-7105
authors: RG
authors: Haverkamp
mesh_terms: D000818:Animals; D002417:Cattle; D003094:Collagen / Q000737:chemistry*; D004548:Elasticity; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D012867:Skin / Q000737:chemistry*; D014463:Ultrasonography
chemical_list: D003094:Collagen
keywords: collagen; electron microscopy; leather; looseness; microstructure; small-angle X-ray scattering; ultrasonics