Characterization of compressed bacterial cellulose nanopaper film after exposure to dry and humid conditions

This work investigates the effects of two different levels of humidity (RH 50% and 75%) on the characterizations of compressed bacterial cellulose nanopaper film. The film was prepared with different heat treatments; compression at 25 degrees C for 72 h and then at 100 degrees C for 24, 72 or 120 h. Maximum tensile strength (250.7 MPa) and tensile modulus (18.6 GPa) were measured on the film treated at 100 degrees C for 120 h and RH 50%. However, tensile strength and tensile modulus dropped by 53.6% and 75.8% respectively and elongation at break increased by 32% when this film was stored in more humid conditions (RH 75%). FTIR spectra and XRD patterns indicate changes of the deformed chain structure of the cellulose as more water was incorporated between the layers of the lattice after exposure to humidity. (C) 2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).