Dynamic loss properties of wood

Internal friction and dielectric loss measurements have been made on whole wood, on cellulose, and on lignin. A prominent β peak is seen at 200 K for frequencies around 1 Hz. This peak shifts to lower temperatures (near 160 K) when wood is heated to 475 K. We propose that this shift signifies molecular changes characteristic of the first stages of coalification of wood and lignin. Additional comparisons are made with the macromolecular structure of amber, oil shale, and synthetic polymers.