Chromium tanned cow hides collected at two different stages (i.e. pre-neutralization and pre-finishing) have been treated separately with acrylic and glutaraldehyde based tanning agents. Both mechanical and hydrodynamic swelling properties of these treated samples were investigated. Observed results revealed that overall tensile properties and resistance against hydrodynamic swelling have been improved in all the treated samples as compared to those of untreated samples. Such improvement has been realized through measurement of crosslink densities via fitment of Mooney-Rivlin equation on the tensile plot. Leather post-treated with acrylic copolymer has envisaged superior results as compared to leather post-treated with gluteraldehyde based tanning agent. After one swelling / deswelling cycle, slight material loss has been incurred in all the samples, which is the highest for leather post-treated with glutaraldehyde. Such post-treatment of leather can be a useful measure to enhance the performance properties of leather samples already manufactured in the tannery.

Four different bag leathers, such as, Sheep Bag Leather (SBL), Buffalo Vegetable Tanned Leather (BVTL), Cow Drum Dyed Dry Milled Leather (CDDDML), and Cow Crocodile Print Leather (CCPL), were processed by different methods from respective wet-blues of Indian origin. Thermal degradation profile and mechanical properties of the samples were evaluated, and crosslink densities of each sample were measured by fitment of Mooney-Rivlin equation on stress-strain plots. Morphological characteristics (e.g. fibre structure, fibre thickness, splitting etc.) of all the specimens were investigated by image analyses of SEM photomicrographs. The highest crosslinking density for BVTL was attributed to its higher fibre and fibril thicknesses coupled with rigorous retanning by vegetable tannins and syntans. Embossing at higher temperature and pressure reduced CCPL's elongation-at-break value and hence stretchiness possibly due to the development of set properties within the CCPL matrix. SBL was noted to contain huge void spaces that increased its stretchiness, and melamine formaldehyde syntans showed pronounced influence in increasing the thermal resistance of both CCPL and CDDDML.