Laboratory of Plastics and Rubber Technology, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, H-1521 Budapest, P.O. Box 91, Hungary.
Carbohydr Polym. 2013 Feb 15;92(2):1767-75. doi: 10.1016/j.carbpol.2012.11.006. Epub 2012 Nov 10.
PLA biocomposites were prepared using three corn cob fractions and a wood fiber as reference. The composites were characterized by tensile testing, scanning electron microscopy (SEM) and polarization optical microscopy (POM). Micromechanical deformation processes were followed by acoustic emission measurements. The different strength of the components was proved by direct measurements. Two consecutive micromechanical deformation processes were detected in composites containing the heavy fraction of corncob, which were assigned to the fracture of soft and hard particles, respectively. The fracture of soft particles does not result in the failure of the composites that is initiated either by the fracture of hard particles or by matrix cracking. Very large particles debond easily from the matrix resulting in catastrophic failure at very low stresses. At sufficiently large shear stresses large particles break easily during compounding, thus reinforcement depending on interfacial adhesion was practically the same in all composites irrespectively of initial fiber characteristics.
PLA 生物复合材料是用三种玉米穗轴部分和一种木纤维作为参考制备的。通过拉伸试验、扫描电子显微镜（SEM）和偏光显微镜（POM）对复合材料进行了表征。通过声发射测量跟踪了微机械变形过程。通过直接测量证明了不同组分的强度。在含有玉米穗轴重部分的复合材料中检测到两个连续的微机械变形过程，分别归因于软颗粒和硬颗粒的断裂。软颗粒的断裂不会导致复合材料失效，复合材料的失效要么是由硬颗粒的断裂引起的，要么是由基体开裂引起的。非常大的颗粒很容易从基体上脱粘，导致在非常低的应力下发生灾难性失效。在足够大的剪切应力下，大颗粒在复合过程中很容易断裂，因此，无论初始纤维特性如何，依赖于界面粘附的增强在所有复合材料中实际上是相同的。
