Lyocell纤丝及其可生物分解的纳米复合材料研究

可生物分解的纳米复合材料是新一代材料,微米和纳米级纤维素纤丝具有环保性和潜在的低密度及高强度,可用来制造能生物分解的纳米复合材料.为了描述用一种新的机械方法从Lyocell纤维中分离出的纤丝的特性,以及探索这种纤丝能否增强生物分解的聚合物,笔者用偏振光显微镜(PLM)和扫描电子显微镜(SEM)研究了纤丝的几何特性,用宽角X光衍射法(WAXD)分析了其结晶度,纤维的纤丝化程度用水分保持值(WRV)进行了评价;纤丝增强的聚乳酸(PLA)纳米生物复合材料由模压法制备,用拉伸试验来检测其力学强度,采用SEM来观察其断面特性.结果表明:纤丝提高了PLA的弹性模量和拉伸强度,但纤丝和聚合物基质之间的结合强度很弱.

Lyocell-derived Cellulose Fibril and Its Biodegradable Nanocomposite

Biodegradable nanocomposite is one of the next generation materials. Cellulose fibrils in micro and nano scales, which are environmentally friendly and have potential lightweight and high strength, can be used to make biodegradable nanocomposites. The purposes of this research were to characterize the fibrils isolated from Lyocell fiber by a novel mechanical process and to discover weather the fibril reinforced biodegradable nanocomposites yield greater mechanical properties. The geometrical characteristics of the fibrils were investigated using polarized light microscopy (PLM) and scanning electron microscopy (SEM), and their crystallinity was investigated by wide angle X-ray diffraction (WAXD). The degree of fibrillation of the fibers is evaluated by water retention value (WRV). Fibril-reinforced nano-biocomposites, consisting of a biodegradable polymer (PLA) and fibrils were prepared by compression molding, evaluated by tensile test, and their morphological characteristics were investigated with SEM. The fibrils increased both tensile modulus and strength of polymer matrix, but a poor adhesion between fibrils and the matrix was still observed by SEM.