Leather Structure Determination by Small-Angle X-ray Scattering (SAXS): Cross Sections of Ovine and Bovine Leather

Abstract

SAXS has been applied to structural determination in leather. The SAXS beamline at the Australian Synchrotron provides 6 orders of magnitude dynamic range, enabling a rich source of structural information from scattering patterns of leather sections. SAXS patterns were recorded for q from 0.004 to 0.223 A(-1). Collagen d spacing varied across ovine leather sections from 63.8 nm in parts of the corium up to 64.6 nm in parts of the grain. The intensity of the collagen peak at q = 0.06 A(-1) varied by 1 order of magnitude across ovine leather sections with the high-intensity region in the corium and the low intensity in the grain. The degree of fiber orientation and the dispersion of the orientation has been quantified in leather. It is shown how the technique provides a wealth of useful information that may be used to characterize and compare leathers, skin, and connective tissue.

Age Dependent Differences in Collagen Alignment of Glutaraldehyde Fixed Bovine Pericardium

“…The structure of these collagenous tissues can be characterized by small angle X-ray scattering (SAXS) to yield, for example, quantitative measures of fibril orientation and fibril D-spacing [5–7]. While other methods have been used to study collagen fibril orientation including polarized light microscopy [8], reflection anisotropy [9], small angle light scattering [10], confocal laser scattering [11], Raman polarisation [12], and anisotropic Raman scattering [13], synchrotron based SAXS has the advantage of excellent nonsubjective quantification combined with good spatial resolution.…”

Artificially modified collagen fibril orientation affects leather tear strength

“…The collagen orientation was determined from the azimuthal angle for the maximum intensity of the D ‐spacing diffraction peaks. The orientation index (OI) was the primary measure used, with OI defined as (90° − OA)/90°, where OA, the orientation angle, is the minimal azimuthal angle range, centered at 180°, that contains 50% of the microfibrils . The OI range takes us from perfect anisotropic alignment which is represented by an OI of 1, through to an OI of 0 which represents isotropy.…”

A small angle X‐ray scattering study of the structure and development of looseness in bovine hides and leather

“…Small angle X‐ray scattering (SAXS) studies of loose and tight leather support the idea that, in loose leather, the collagen fibrils are more layered, exhibiting a higher orientation index (OI) than in tight leather when the OI is measured with the X‐rays edge‐on to the leather . SAXS has been shown to be valuable in improving our understanding of the structure of leather and its relation to other physical properties, such as tear strength and the response to strain . The overall goal of the present study is to determine how looseness develops during the processing of bovine hides to dry crust.…”