The Structure and Properties of Ultrathin Films Blended from Nanofibrils of Natural Fibers.

本研究利用天然纳米原纤维（NFs）制备了一种新型可生物降解超薄膜，并对其表面结构和力学性能进行了分析。以木浆（漂白硫酸盐浆、纤维素）、壳聚糖（商品级）和胶原蛋白（牛皮废料）三种天然纤维为原料。一个带有特殊设计的圆盘的小型商用研磨机被用来对天然纤维进行纳米纤化。所有物料被控制为含有90% - 99%水的浆料。木浆制备的纳米颗粒直径约为几纳米，壳聚糖和胶原蛋白制备的纳米颗粒直径约为十纳米。以NFs的水悬浮液为原料制备了一种新型超薄膜。这些薄膜的厚度从几百纳米到几十纳米不等，具有均匀、坚固和半透明的特点。该方法在不使用有机溶剂的情况下，可以很容易地获得三种NFs的超薄膜。通过结构分析，将超薄膜中的每个NFs定向为与其表面平行。通过对纳米纤维进行微纤化制备其超薄薄膜，并与溶剂浇铸法制备的普通薄膜进行了对比。现在，我们能够制备出具有多种用途的混合薄膜。由木浆、壳聚糖和胶原蛋白混合制成的薄膜约为印刷级纸的1.5倍，约为聚乙烯的2倍。这些薄膜的值对于实际应用是足够的。

In this study, a new type of the biodegradable ultrathin films have been developed using natural nanofibrils (NFs), and the surface-structure of their ultrathin films and mechanical properties are analyzed. Three kinds of natural fibers, wood pulp (bleached kraft pulp, cellulose), chitosan (commercial grade) and collagen (cow hide waste) were used as raw materials. A small commercial grinder with a specially designed disk was used to nanofibrillate the natural fibers. All the materials were controlled as a slurry containing 90 - 99 % water. The diameter of their NFs from wood pulp was about some nanometer and the diameter of the some ones from chitosan and collagen were some ten nanometer. A new type of ultrathin film was made from the water suspension of NFs. The thicknesses of these films were from about some hundreds nanometer to about some tens nanometer, being homogeneous, strong and translucent. The ultra thin films of three kinds of NFs were easily obtained by this water-suspension method without using an organic solvent. Each NFs in ultrathin films is oriented to parallel to its surface plane by structural analysis. The formation process of their ultrathin films was made by microfibrillating the NFs, and then their networks of microfibril were compared with the ordinary films of solvent-cast method. Now, we are able to prepare thin hybrid films which are expected for many uses. The thin film from the mixture of wood pulp, chitosan and collagen was about 1.5 times of that of print grade paper and about 2 times of that of polyethylene. These values of the films are sufficient for practical use.