Effect of Chrome-Tanning Process on Bovine Hide Using Dynamic Mechanical and Thermal Analysis (DMTA)

Abstract

The study reports the Dynamic mechanical Analysis of leather at pickling and tanned stage of processing. The study also discusses the effects of these two key processes in leather making on the viscoelastic properties. The technique of analysis has enabled recording of changes in the viscoelastic properties related to quality and hence functional performance as leather is further processed from pickling to tanning. Dynamic Mechanical Thermal Analysis of bovine hide can be to qualify and quantify leather tanning processes. The results have shown the possibility of using the technique to customize each leather tanning processes for specific application fields. Tanning enhances the E^', σ, and thermal stability while decreases E^'', loss factor, viscosity and ε. All the viscoelastic properties exhibited dispersion with two distinct frequency range: 0.1-30 and 30-100 Hz. The dominantly elastic nature of hides implies that the majority of the mechanical energy is dissipated by elastic deformation. Tanning: enhances 〖E'〗^' at frequencies lower than 30 Hz but lowers E^'' at higher frequency than 30 Hz, increases E^' at all frequencies and temperatures. Viscoelastic properties become less frequency-dependent at frequencies higher than 30 Hz. The viscoelastic properties investigated showed to increase with temperatures before drastic drop at specific temperatures. Tanned hide stores more residue stress and its molecular chains are easier to slide over each other when shearing forces are applied than pickled hide while pickled hide dissipates more than tanned hide at all temperatures and frequencies.