Interactions Between Collagen and Alternative Leather Tanning Systems to Chromium Salts by Comparative Thermal Analysis Methods

This study aims to investigate the interactions between collagen and tanning processes performed by ecol-tan^®, phosphonium, EasyWhite Tan^®, glutaraldehyde, formaldehyde-free replacement synthetic tannin (syntan), condensed (mimosa) and hydrolysed (tara) vegetable tanning agents as alternatives to conventional basic chromium sulfate, widely used in the leather industry. Collagen stabilisation with tanning agents was determined by comparative thermal analysis methods: differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and conventional shrinkage temperature (T_s) measurement. Analysis techniques and tanning agents were compared and bonding characteristics were ranked by the thermal stabilisation they provided. Chromium tanning agent was also compared with the alternative tanning systems. The results provide a different perspective than the conventional view to provide a better understanding of the relationship between tanning and thermal stability of leather materials.