Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan.
Biomacromolecules. 2011 Mar 14;12(3):617-24. doi: 10.1021/bm101280f. Epub 2011 Feb 4.
To exploit the maximum potential of cellulose whiskers (CWs), we report here for the first time the successful fabrication of nanocomposites reinforced with highly oriented CWs in a polymer matrix. The nanocomposites were prepared using polyvinyl alcohol (PVA) and a colloidal suspension of cotton-derived CWs. The macroscopically homogeneous PVA-CW suspensions were extruded into cold methanol to form gel fibers followed by a hot drawing. Compared to the neat PVA fiber, the as-spun fiber containing a small amount of CWs (5 wt % of solid PVA) showed higher drawability, leading to an extremely high orientation of CWs with the matrix PVA. The stress-transfer mechanism, a prime determining factor for high mechanical properties of nanocomposites, was studied by X-ray diffraction. The stress on the incorporated CWs was monitored by applying an in situ nondestructive load to the composite fibers. The applied stress to the whole sample was found to be effectively transferred to the CWs inside the composites, suggesting strong interfacial bonding between the filler and the matrix. Effective stress transfer to the oriented whiskers resulted in outstanding enhancement in mechanical properties of the nanocomposites.
为了充分发挥纤维素晶须 (CWs) 的潜力，我们首次成功地在聚合物基体中制备了高度取向的 CWs 增强纳米复合材料。纳米复合材料是由聚乙烯醇 (PVA) 和棉衍生的 CWs 的胶体悬浮液制备的。将宏观均匀的 PVA-CW 悬浮液挤出到冷甲醇中形成凝胶纤维，然后进行热拉伸。与纯 PVA 纤维相比，含有少量 CWs（固体 PVA 的 5wt%）的初生纤维具有更高的拉伸性，导致 CWs 与基体 PVA 具有极高的取向度。通过 X 射线衍射研究了影响纳米复合材料力学性能的主要因素——应力传递机制。通过对复合纤维施加原位无损载荷来监测掺入的 CWs 上的应力。发现施加在整个样品上的应力有效地传递到复合材料内部的 CWs 上，表明填充剂和基体之间具有很强的界面结合力。有效的应力传递到取向的晶须上，导致纳米复合材料的力学性能得到显著提高。
