NMR imaging study of stress-induced material response in rubber modified polyamide 6
NMR imaging study of stress-induced material response in rubber modified polyamide 6
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DOI：
10.1021/ma0113273
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发表时间：
2002-01-01
期刊：
影响因子：
5.5
通讯作者：
Crevecoeur, J
中科院分区：
文献类型：
--
作者：
Adriaensens, P;Storme, L;Crevecoeur, J
通过磁共振成像 (MRI) 检查两种不同类型的挤出聚酰胺 6 (PA6)/马来酸酐接枝乙烯-丙烯 (EPM-g-MA) 共混物的断裂行为。 TEM 显微照片显示出明显的形态差异：一种共混类型包含分散在 PA6 基体中的纯橡胶颗粒，另一种类型则包含橡胶颗粒内的 PA6 吸留物，并且韧性明显更高。在临界载荷下对两种共混物类型的缺口样品进行的 MRI 实验表明，橡胶空化现象朝着裂纹尖端逐渐增加，这可以根据局部质子自旋密度进行量化。在韧性和塑性区尺寸之间观察到明显的关系：最坚韧的共混物在裂纹尖端之前具有明显更延伸的塑性区。具有咬合的共混物韧性的增强可归因于更明显的能量离域，这表明这是由不同的变形机制引起的，其中橡胶链的承载能力起着重要作用。
The fracture behavior of two different types of extruded polyamide 6 (PA6)/maleic anhydride grafted ethylene-propylene (EPM-g-MA) blends is examined by magnetic resonance imaging (MRI). TEM micrographs demonstrate a clear difference in morphology: where one blend type contains pure rubber particles dispersed in the PA6 matrix, the other type contains PA6 occlusions within the rubber particles and is significantly more tough. MRI experiments on notched specimens of both blend types under critical load reveal a gradual increase of rubber cavitation toward the crack tip which can be quantified on the basis of the localized proton spin density. A clear relation is observed between the toughness and the dimensions of the plastic zone: the toughest blend has a significant more extended plastic zone ahead of the crack tip. The enhanced toughness of the blends with occlusions can be attributed to a more pronounced delocalization of energy, which is suggested to result from a different deformation mechanism in which the load bearing capacity of the rubbery chains plays an important role.