Effect of the interaction between wood constituents and swelling liquid on the creep properties of wood during drying

This study aimed to clarify the effect of the interactions between the swelling liquid and wood constituents on the creep behavior during drying. Creep tests were conducted during drying of four sample groups (untreated, acetylated, delignified, and hemicellulose-extracted samples) that were swollen using water, one organic liquid, or water-organic mixtures. The largest creep deformation was measured for the hemicellulose-extracted samples, followed by delignified, untreated, and acetylated samples. Apart from the acetylated samples, all treated samples tended to have large creep deformation in water-organic mixtures. For the acetylated samples, the creep deformation was small, except in case of acetone. These differences in the creep deformation behavior are mainly due to the differences in the glass-transition temperature of lignin as a result of the interaction between the wood constituents and the swelling liquid. The considerable increase in creep deformation due to hemicellulose-extraction suggests that hemicellulose, which interacts with lignin and cellulose, reduces the fluidity of the wood due to liquid desorption during creep measurements.