Application and valorization of novel indigenous Azadirachta indica leaf in leather processing

This study investigated the viability of locally available organic sources of Azadirachta indica leaf as vegetable tannin agent in leather processing to promote green leather manufacturing. Leather tanned with Azadirachta indica leaf powder (NPT), extract (NET) and conventional vegetable tanned leather (CVT) was characterized with FTIR, DLS, HPLC, DSC, TGA, and SEM. Total soluble solid, pH, tannin content, and tanning strength of Azadirachta indica leaf extract were found to be 24 %, 4.81, 12.34 % and 1.81 respectively. Moisture content, fat content, and water-soluble content of Azadirachta indica leaf extract tanned leather (NET) were 12.26 %, 10.8 % and 7.2 % respectively. The shrinkage temperature, tensile strength, stitch tear strength, grain crack load, and finished film bond strength of NET leather were 86 °C, 282.52 kg/cm², 139.53 kg/cm, 24 kg, and 414 g/cm respectively. NET leather exhibited better anti-microbial sensitivity against E. coli, S. aureus, and P. aeruginosa than NPT and NET leather. Overall, the experimental results of this study indicate the A. indica leaf could serve as a prime renewable tanning agent, substituting hazardous chromium and imported conventional vegetable tannin chemicals in leather manufacturing. Thus, developed A. indica leaf tannin material from plant sources could provide sustainable leather production, contributing to eco-friendly and viable green leather processing options.