Change in the Crystallite Orientation of Poly(ethylene oxide)/Cellulose Nanofiber Composite Films.

The crystallite orientation and crystallographic domain structure of poly(ethylene oxide) (PEO) in cellulose nanofiber-incorporated (CNF-incorporated) PEO films developed for packaging materials were observed using wide-angle X-ray diffraction for different CNF filling ratios. When a CNF filling ratio of <10 wt % was used, the molecular chains in the PEO crystallite region were oriented in a direction perpendicular to the surface of the film; however, when the ratio was >50 wt %, the PEO molecular chains were oriented in a direction parallel to the surface of the film. The fiber axis of the CNFs became parallel to the surface of the PEO/CNF composite film when the filling ratio was >25 wt %.