Influence of drying treatment on density of cellulose nanofiber sheet

The density of cellulose nanofiber (CNF) sheets is strongly related to their physical properties for various applications. We investigated the effects of restraint drying on the density of CNF sheets. Furthermore, the density of the sheet was measured before and after cyclic wetting and drying. The CNF suspension was filtrated with a membrane filter under reduced pressure to prepare a CNF wet sheet. Hot-press drying could produce the visually flattest CNF sheet among the “hot-press drying”, “restraint drying”, and “unrestraint drying” processes. The density of the CNF sheet prepared at room temperature was higher than that prepared at 105 °C. The density of the CNF sheet prepared at 105 °C also increased with cyclic wetting and drying. © 2018 The Society of Fiber Science and Technology, Japan.