Studies on the Physico-chemical Behavior of Synthetic Tanning Agents in Non-Aqueous Medium

Abstract

Green labelling is a high priority issue in the modern society thathas lead to several green technology initiatives in day-to-dayapplications. Among the several industry sectors, leatherindustry, is known to contribute to environmental pollution.Though, there are several alternate cleaner technologiesavailable, till date no drastic shift in methodologies of cleantechnology has been implemented. In our efforts to use ‘green’methodologies, in the present investigation, we have chosengreen solvents like ethanol and heptane as possible carriermedium for synthetic tanning agents in leather processing.These tanning agents are performance chemicals that impartspecial properties to leather depending on end applications. Inthis study, tunable interfacial properties that arise between thesolvated syntans and different solvents + water mixtures havebeen employed judiciously. Representative class of synthetictanning agents have been chosen for the evaluation. Theinterfacial properties of liquid/liquid (solution) have beenexamined to understand the influence of solvents in the posttanning applications in leather making. Physical characteristicslike tensile and tear strength have been determined forexperimental leathers. Results show that syntans in ethanol andheptane medium form uniform dispersion and act as diffusingvehicle. The results suggest that the bound and unbound waterin the leather matrix can form interfacial tension gradient withthe solvent enabling effective diffusion of the chemicals evenwith non-polar solvents like heptane. Physical strengthcharacteristics of experimental leather have met standard norms.The results have demonstrated an insight into the fundamentalbehavior of syntans in non-aqueous medium and provide cluesfor real time application in leather processing.