Suitability of Pore Measurement Methods for Characterizing the Hierarchical Pore Structure of Leather

Pore structure of leather plays an important role in leather making process as well as in characterization of comprehensive properties of leather. In this study, scanning electron microscopy, mercury intrusion porosimetry (MIP), capillary flow porometry and nitrogen adsorption techniques were used for characterization of the hierarchical pore structure of leather. From the comparison, MIP was found to be more suitable for pore measurement of leather in consideration of its extensive measuring range (from 5.48 nm to 120 mu m), high accuracy (measuring both through pores and blind pores in leather) and satisfactory repeatability (with RSD of 3.25% and 1.73% for average pore diameter and porosity, respectively). Then the MIP test conditions were optimized. The appropriate conditions were found to be that a leather sample (approx. 3 cm x 2 cm and 0.6 g) is used for determination with a stem volume around 50%. Blank correction is conducted in the measurement with the maximum pressure of 33000 psia and the equilibration time of 10 s. In general, the characterization of the hierarchical pore structure of leather by MIP is a meaningful aid to explore the relationship between structure and property of leather.