The effect of wood drying on crystallinity and microfibril angle in black spruce (Picea mariana)

The effect of drying on wood cellulose crystallinity, crystallite size, and microfibril angle was investigated using wide angle X-ray diffraction. Forty replicated specimens of black spruce (Picea mariana) wood were dried at constant temperatures of 40 degrees C and 80 degrees C and relative humidities of 34% and 47% in attempts to attain samples possessing final moisture content of 15% and 8% at each temperature. X-ray evaluation of wood specimens, comparing individual samples pre- and post-drying, revealed that both the mass fraction of crystalline cellulose and crystallite width increased with drying. In contrast, mean microfibril angle of the wood was not significantly affected by drying. It was also apparent that the changes in wood ultrastructure resulting from drying were not influenced by the drying conditions, including temperature, relative humidity, and final moisture contents.