PPO/SEBS-g-MAH共混体系的冲击断面和微观形变过程

IMPACT FRACTURE SURFACE AND MICROSTRUCTURAL DEFORMATION PROCESS OF PPO/ELASTOMERIC STYRENE-BASED BLOCK COPOLYMERS BLENDS

用扫描电子显微Ｗ（ＳＥＭ）观察了 ＰＰＯ／ＳＥＢＳ和 ＰＰＯ／ＳＥＢＳ－ｇ－ＭＡＨ共混物的常温缺口冲击断面，发现 ＰＰＯ／ＳＥＢＳ共混体系的冲击断面上有大量韧窝； ＰＰＯ／ＳＥＢＳ－ｇ－ＭＡＨ共混体系则呈现中心为棒，四周为环的冲击断面形貌对 ＰＰＯ／ＳＥＢＳ－ｇ－ＭＡＨ冲击断面的应力发白区的 ＳＥＭ观察结果表明在冲击断面下方，合金发生大的取向；ＴＥＭ的观察结果显示在应力发白区内，弹性体周围存在大量的微穴。

The fracture sufraces of various PPO/SEBS (Kraton G 1651) and PPO/SEBS-g- MAH (Kraton FG 1901) blends at 23℃ by the standard lzod impact test were tested be using SEM. The results showed that for PPO/SEBS(80.0/200mg.g-1) there were lots of patch pattern which exhibited ductile fracture. For PPO/SEBS-g-PAH blends, one core bar occured at the center of fracture surface, around which there were circles. Microstructural process happened at high speed impact were examined by microscopy. SEM studies showed that high orientation occured at stress-whitened zone. TEM observations of stress-whitened zone revealed that a large sum of cavities were formed during impact process. TEM observations of the region near the crack tip showed that microcavitation was the main process of releasing hydrostatic tensile siress.