哑铃形碳化硅晶须增强聚氯乙烯(PVC)复合材料的制备和性能　

PVC COMPOSITE REINFORCED BY DUMBBELL-SHAPED BIOMIMETIC SiC WHISKERS

研究了平直晶须和哑铃形仿生ＳｉＣ晶须增强聚氯乙烯（ＰＶＣ）复合材料的微观结构和力学性能 结果表明，与平直ＳｉＣ晶须相比，哑铃形仿生ＳｉＣ晶须在提高复合材料强度的同时还成倍地提高其延伸率，由于仿生晶须上小球的存在使复合材料中各部位处于均匀受力状态．裂纹不易在局部过早形成．同时，由于仿生晶须在拔出过程中起桥连的作用、所以复合材料的强度降低很小而延伸率得以增加， 在加载过程中仿生晶须逐渐从ＰＶＣ基体中拔出，在达到晶须断裂强度时在球颈处发生断裂， 由于仿生晶须的增强和增韧机理是通过晶须上的小球在基体和晶须之间传递应力，因此其增强、增韧效果对于复合材料中的界面结合情况是不敏感的。

PVC composite can be reinforced by dumbbell-shaped biomimetic SiC whiskers. The microstructure and mechanical property of the reinforced composite were investigated by tensile and SEM. The elongation rate of the biomimetic SiC whiskers composite was several times higher than that of the composite reinforced by plain SiC whiskers while the strength was only a little lower. The stress of the PVC composite is uniform and the formation of the fissure is difficult in the composite because of the existence of the beads on the biomimetic SiC whiskers. At the same time the biomimetic SiC whiskers also have the connection effective in the matrix when they are pulled out, so the elongation rate of the composite is higher. The beads can be pulled out from the matrix and make the matrix deform and crack, but the biomimetic SiC whiskers can not be pulled out completely, till fracture at the neck of the beads when the stress is high enough. The stress can be transferred by the beads from the matrix to the biomimetic whiskers, so the mechanical properties of the composites were insensitive to the interface between the matrix and the whiskers.