Assessment of tannins extracts of Acacia nilotica ssp Adansonii pods and Azadirachta indica bark on leather processing

Abstract

Despite the fact, world leather industries are built on chromium tannage system, there is a growing interest of metal free tannages (chrome). This is primarily owing to the rising demand for chromium free tanning in the leather industry. The goal of this research paper was to evaluate the influences of vegetable tannins materials on the retannage of leather, by using Acacia nilotica ssp Adansonia pods (hydrolysable tannins) and Azadirachta indica bark (condensed tannins), and estimating the absorption and physico-mechanical properties of leather. The results indicated that this system of free chromium tannage give us products with tear strength of 80 N/mm, tensile strength of 55.5 N/mm2, and elongation at break (75.3%). A vegetable re-tanning produced strong leather with durable properties. On other hand, vegetable pre-tanning (condensed tannins) probably stiffens the fiber network of collagen molecules, blocking the bigger molecules from diffusing into the fibers of collagen.