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 %. The change in the orientation of the PEO crystals occurred because increasing the amount of CNF in the composite films decreased the space in which the PEO could be crystallized. Furthermore, the hydrogen bonds between the PEO and the CNF may behave as crystallization nuclei for the PEO. Our results thus pave the way toward the development of packaging materials that are more impermeable to gases than the current materials.

中文翻译：

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聚环氧乙烷/纤维素纳米纤维复合薄膜微晶取向的变化

使用广角X射线衍射对不同的CNF填充率，观察了为包装材料开发的纤维素纳米纤维掺入（CNF掺入）PEO薄膜中聚环氧乙烷（PEO）的微晶取向和晶体学域结构。当使用＜10wt％的CNF填充率时，PEO微晶区域中的分子链沿垂直于膜表面的方向取向；因此，PEO微晶区域中的分子链沿垂直于膜表面的方向取向。然而，当该比例＞ 50wt％时，PEO分子链沿平行于膜表面的方向取向。当填充率＞ 25wt％时，CNF的纤维轴变得平行于PEO / CNF复合膜的表面。由于增加复合膜中CNF的量减少了PEO可以结晶的空间，因此发生了PEO晶体取向的变化。此外，PEO和CNF之间的氢键可以充当PEO的结晶核。因此，我们的结果为开发比当前材料更不透气的包装材料铺平了道路。