Effect of Pressure Treatment on Structure and Mechanics of Crust Leather

Chemical modification has traditionally resulted in good leather mechanical properties; but this approach incurs high costs and contributes to significant environmental pollution. A physical approach can enhance the mechanics of leather, while lowering its cost and environmental load. In this study, the Cr-tanned crust leather was treated by pressures from 0 MPa to 37.5 MPa, significantly improving mechanical properties such as tensile (by 108%) and tear strength (205%) without adding any chemicals or reducing softness. Pressure treatment altered the diameter and D-spacing of fibrils and deformed the pore-size distribution. The higher tensile properties (32.6 to 67.9 MPa) of crust leather were obtained with pressure increasing, resulting in a reduced pore diameter (1142 to 212 nm) and larger specific surface area (3.2 to 6.4 m2/g). Pores in crust leather were categorized into 5 types by fractal dimension, and the properties (elongation at break, softness, and tear strength) were associated with pores of diameter below 200 nm. This study offers a novel approach to enhancing the mechanical properties of leather without using additional chemicals, resulting in cleaner leather processing