Submitted to: Proceedings of American Chemical Society National Meeting
Publication Type: Proceedings
Publication Acceptance Date: 5/2/2007
Publication Date: 8/1/2007
Citation: Liu, C. 2007. Hysteresis and Stress Relaxation Studies for a Fibrous Collagen Material: Chrome-free Leather. American Chemical Society, Division of Polymeric Materials: Science and Engineering. PMSE Preprints. 97:905-906. Interpretive Summary:
Technical Abstract: Animal hides are the most valuable coproduct of the meat industry, and most of those hides are converted into leather. Due to concerns over the use and disposal of chrome-tanned leather, the leather industry is now facing increasing scrutiny over its use of chrome as a tanning agent. The use of non-chrome tannages has gradually become pre-eminent to producing leather, particularly in the European automotive leather markets. Chrome-free leather is tanned using organic tannages, a more environmentally friendly production method, in place of using chrome salts. Many tanneries have started to provide chrome-free leather to meet their customer's special needs for leather in such items as children's and health care leather products. In some respects, however, the quality of current chrome-free (non-chrome-tanned) leather, such as glutaraldehyde-tanned leather, is inferior to that of chrome-tanned leather, for example, lower resiliency, UV resistance, and hydrothermal stability. As reported previously, we investigated several methods to improve the properties of chrome-free leather. This report focuses on the viscoelasticity of chrome-free leather. In many respects, chrome-free leather behaves very differently from chrome-tanned leather. The viscoelasticity of chrome-free leather has not been previously reported. Hysteresis and stress relaxation are two essential properties tied with viscoelasticity. We have designed a cyclic tensile test to measure these two properties to gain insight into the structural difference of chrome-free leather from chrome-tanned leather.