Combining mercury intrusion porosimetry and fractal theory to determine the porous characteristics of wood

The understanding of pore characteristics is the basis for studying the macroscopic physical properties of wood. Herein, mercury intrusion porosimetry (MIP) was analyzed in detail as a function of pressure to analyze wood samples. Additionally, fractal analysis was performed from the MIP derived data to establish the relationship between the fractal dimension and the structural parameters. The results demonstrate that in spite of the large variability of the MIP data from different wood species, the overall trend can be approximated. The aperture size ranged from 2.0 nm to 350 mu m with a corresponding porosity ranging from 44.26 to 73.18%. The threshold pressure, average pore radius and pore-to-throat ratio extracted from the MIP data can be used as a valid parameter to evaluate the structural characteristics. The fractal dimension values in the corresponding macropore, mesopore and micropore aperture range intervals are 2.978, 2.827 and 2.438, respectively, which indicate a higher degree of pore complexity for larger pores. Negative correlations are observed between the fractal dimension and porosity with R-2 values of 0.85, and in addition, positive correlations are observed between the fractal dimension and the average pore radius and pore-to-throat ratio with corresponding R-2 values of 0.66 and 0.52, respectively.