Transparent Woody Film Made by Dissolution of Finely Divided Japanese Beech in Formic Acid at Room Temperature

A new transparent flat woody film was developed by direct dissolution of finely divided Japanese beech wood in formic acid at room temperature for 4-7 days and subsequent slow evaporation of the solvent on a substrate. The obtained woody film was bendable and foldable without breaking (it could be used for origami) and had a relatively high Young's modulus and tensile strength. The thermal analyses showed that the woody film was mechanically and thermally stable even at relatively high temperatures and can be utilized up to 180 degrees C without softening. The film absorbed almost the same amount of water as that absorbed by the cellulose film and had very high biodegradability, which was comparable with that of cellulose. The film was prepared without removing any constituents from wood and using a very simple processing method. We think that this work opens the way for the production of biodegradable and sustainable "molded wood" materials.