Evaluation of the Impact of Iron on Structural deterioration of Chrome Leather in Buried Conditions, Based on Degradation Indices in FTIR Spectra

Iron and its corrosion products are among the effective factors in the degradation of leathers, especially in buried specimens. Therefore, the aim of this study is to evaluate the effects of iron corrosion products on leather deterioration. Accordingly, a buried leather sample obtained from historic “Khosravi” Leather Factory, Tabriz Islamic art university, was examined. Based on appearance, the leather was buried in the vicinity of the iron and its corrosion products. Structural evaluation of different parts of the leather and their deterioration was performed by spot test of iron, leather ash measurement, μ-XRF, UV-Vis and FTIR spectroscopy and microscopic examination. FTIR spectra were also fitted to the Gaussian function. The results showed that this sample was tanned with chromium salts and, probably, lime was used for dehairing. Examination of leather showed that the amount of iron varied in different parts of leather. In other words, a part of the leather has been in direct contact with iron and, over time, corrosion products have penetrated the leather structure. This has led to differences in the amount of iron in different parts of leather. Examination of the structural properties of these parts showed that as the amount of iron in the leather increased, the integrity of triple-helical structure of collagen collapsed and its hydrolysis increased. And it also has increased collagen oxidation.