Synchrotron radiation small-angle X-ray scattering study on fracture process of carbon nanotube/poly(ethylene terephthalate) composite films
Synchrotron radiation small-angle X-ray scattering study on fracture process of carbon nanotube/poly(ethylene terephthalate) composite films
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DOI：
10.1016/j.compscitech.2007.04.005
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发表时间：
2007-12
影响因子：
9.1
通讯作者：
Haruki Kobayashi;M. Shioya;Tomoya Tanaka;Toshihira Irisawa
中科院分区：
文献类型：
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作者：
Haruki Kobayashi;M. Shioya;Tomoya Tanaka;Toshihira Irisawa
利用同步辐射时间分辨小角X射线散射（SAXS）技术研究了碳纳米管（CNT）/无定形聚对苯二甲酸乙二醇酯（PET）复合薄膜拉伸变形过程中的断裂过程。所观察到的SAXS图案包括由银纹/聚合物界面处的全反射引起的平行于加载方向的条纹、由银纹的纤维/空隙结构和来自CNT的散射引起的垂直于加载方向的条纹。根据小角X射线衍射（SAXS）谱图的变化，研究了银纹的形成、扩展和断裂过程，并用基本断裂功法测定了复合膜的断裂韧性。CNT添加对PET的机械性能的影响根据用于机械测试的试样几何形状而变化，并且用表面缺口试样获得显著的影响。CNT的加入增加了银纹加宽所需的能量，并延缓了变形过程中银纹的生长和断裂。这导致PET的断裂塑性功和断裂韧性增加。然而，在CNT分数超过3wt%时形成的CNT聚集体引起断裂韧性的降低。
Time-resolved small-angle X-ray scattering (SAXS) measurements have been conducted during tensile deformation of carbon nanotube (CNT)/amorphous poly(ethylene terephthalate) (PET) composite films using synchrotron radiation in order to investigate the fracture process. The observed SAXS patterns consisted of the streaks parallel to the loading direction caused by the total reflection at craze/polymer interfaces, the streaks perpendicular to the loading direction caused by the fibril/void structure of crazes and the scattering from CNTs. The formation, widening and fracture processes of the crazes were investigated based on the changes of SAXS patterns during deformation and the fracture toughness of the composite films determined with essential work of fracture method. The influences of CNT addition on the mechanical properties of PET varied depending on the specimen geometries used for the mechanical tests and marked influences were obtained with surface-notched specimens. The CNT addition increased the energy needed to widen the crazes and retarded the growth and fracture of the crazes during deformation. This lead to the increases in the plastic work of fracture and the fracture toughness of PET. The CNT aggregates formed at the CNT fraction beyond 3wt%, however, caused reduction of the fracture toughness.