Mechanical properties and shrinkage temperature of a leather tanned using extract of cashew nut testa (NILEST-Tan C)

Abstract

Considering the environmental impact poised by chrome tanning agent in the leather industries, NILEST-Tan C was developed as an alternative tanning agent which is organic in nature and eco-friendly. The percentage offer of the tanning agent was varied as, 3 %, 6 %, 9 %, 12 %, 15 % and 30 % for control. Consequently, the tanned leathers were characterized based on their mechanical properties and shrinkage temperature. Mechanical properties such as tensile strength, percentage elongation and ball-burst of the tanned leathers increased with increase in the percentage offer of the tanning agent. The optimum tensile strength obtained at 15 % offers of the NILEST-Tan C was 25.41 MPa which is relatively higher than the control (crude testa powder) having 24.09 MPa at 30 % offers. In the case of % elongation, 12 % offer recorded the highest % elongation of 66.26 % and the control (crude testa powder) is 56.49 % at 30 % offer. The thermal properties of the tanned leathers in terms of shrinkage temperature were studied and 15 % offer of NILEST-Tan C has the highest shrinkage temperature of 72ºC, while the control (crude testa powder) at 30 % offer registered a shrinkage temperature of 74ºC. Thus, considering the good tensile strength recorded by the leathers, the tanned leathers can be used as shoe upper leather, upholstery and garment leather owing to the fact that the standard minimum value is 12 MPa.