2026 Volume 105 Issue 1 Pages 19-26
Cellulose nanofibers (CNFs) are materials produced from cellulosic pulp derived from renewable woody biomass and fibrillated to the nano size in width, and is expected to be alternative to fossil-based plastic gas barrier packaging materials. There are many reports of gas barrier films made by coating with chemically modified CNFs such as a TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) oxidized CNF, however low drying efficiency is one of the problems. On the other hand, although the mechanically nanofibrillated CNF has relatively high drying efficiency with chemically modified CNFs, there are few examples of its use as a gas barrier material. To produce the gas barrier thin films, a thin film transfer method based on the formation of wet paper of mechanically fibrillated CNF using paper-making technology was established, and the effect of CNF thin film on gas barrier properties were investigated. The paper-making technology was applied to the formation of a mechanically fibrillated CNF thin film with a basis weight of 7.5 g/m2 and its transfer onto a filter paper substrate, enabling the formation of sheets with an oxygen barrier property. This study shows that thin films of mechanically fibrillated CNF with oxygen barrier properties can be fabricated by the papermaking method using paper as the base material. In addition, the fact that there were sheets with high oxygen barrier properties even when mixed with unfibrillated fibers suggests that the formation of mechanically treated CNF thin films by this method will lead to higher efficiency in the nanofibrillation, dewatering, and drying processes.
