COMPARATIVE STUDY OF PHYSICO-CHEMICAL PROPERTIES OF LEATHERS TANNED WITH INDIGENOUS CAESALPINIA CORIARIA AND ACACIA NILOTICA

Abstract

Since the character of leather is determined by the first tannage, there has been a global surge in the search for alternative vegetable tanning materials that are eco-friendly. In this study, the physico- chemical properties of Acacia nilotica (Bagaruwa) and Caesalpinia coriaria (Divi-divi) tanned leathers were compared. The comparison was done with the aim of developing Caesalpinia coriaria in order to reduce the over dependence on Acacia nilotica as the sole vegetable tanning materials which has found commercial application in the country. The result for the shrinkage temperature, indentation index and light fastness, were found to be the same for both tannages (72oC, 8mm and 3.0 rating, respectively). Variations occurred in other results for both Acacia nilotica and Caesalpinia coriaria  tanned leathers in the respective order: tensile strength (37.05N/mm2 and 34.34N/mm2), elongation at break (84.65% and 85.28%), [hide substance (255.71% and 247.84%), combined tannins (214.90% and 197.98%), degree of tannage (84.04% and 79.88%)], soluble matter (43% and 34%), fat content (8.50% and 9.30%), ash content (0.7% and 0.4%), moisture content (6.99% and 6.4%), [fullness of leathers (9980.38kg/cm2 and 4505.10kg/cm2] amongst others.  The offer for both tans was 30% of the crude material. The tanning process variables for both materials were done under the same conditions.  From the result presented, it is evident that indigenous Caesalpinia coriaria has a great potential for the tanning industry, especially the traditional tanneries in the country. Keywords: Acacia nilotica, Caesalpinia coriaria, physico-chemical properties and tannins.