The Chemical Degradation of Leather

The chemical deterioration of vegetable tanned leather is caused by acid hydrolysis and oxidation due to environmental deteriorative factors like air pollutants, heat and light. In addition, the type of tannin material influences the rate of deterioration. The degree of deterioration can be measured by the fall in the shrinkage temperature (Ts) of the leather. New analysis of data shows that, although environmental factors have a generally larger influence on the deterioration, the average degree of oxidation is greater in older leathers and it significantly influences the Ts in these materials. Moreover, it is also shown that acid pollution is indicated in the relation between pH and the sulphate content measured in the leathers although ammonia is released by oxidation of amino acids and may influence the pH value in acid-damaged leathers