摘要
应用扫描电子显微镜(SEM)研究乙烯-丙烯嵌段共聚物和聚乙烯/聚丙烯共混物的冲击断裂表面形态。结果表明,这二种材料力学性能的差别,明显地反映在它们的断面形态上。前者显示出一种典型的韧性断裂特征;后者则呈现出一种剥离层状结构。^(13)C-NMR分析结果表明,在上述乙烯-丙烯嵌段共聚物中,确实存在着乙烯-丙烯共聚链段。这是该材料具有良好的抗冲击性能的主要原因。
The difference of mechanical properties between ethylene-propylene block copolymer andpolyethylene/polypropylene blend was revealed by their fracture morphologies, having a ty-pical feature of toughness fracture with the former and a peeled layered structure with the latter,which were obtained by scanning electron microscopy. The existance of ethylene-propylene seg-ments in ethylene-propylene block copolymer indicated by ^(13)C-NMR spectrum contributes tothe strength of this material.
关键词
乙烯
丙烯
嵌段共聚物
断面形态
Fracture morphology
toughness fracture
sequencal structure
ethylene-propylene segment
