Uniaxial deformation of overstretched polyethylene: In-situ synchrotron small angle X-ray scattering study
Uniaxial deformation of overstretched polyethylene: In-situ synchrotron small angle X-ray scattering study
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DOI：
10.1016/j.polymer.2007.06.056
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发表时间：
2007-08
期刊：
影响因子：
4.6
通讯作者：
Yujing Tang;Zhiyong Jiang;Yongfeng Men;L. An;H. Enderle;D. Lilge;S. Roth;R. Gehrke;J. Rieger-J.-R
中科院分区：
文献类型：
--
作者：
Yujing Tang;Zhiyong Jiang;Yongfeng Men;L. An;H. Enderle;D. Lilge;S. Roth;R. Gehrke;J. Rieger-J.-R
利用同步加速器小角X射线散射研究了超出自然拉伸比拉伸的高密度聚乙烯的变形机制。对微纤维滑移介导的协同变形行为有了新的认识。散射数据一方面证实了Peterlin提出的关于取向聚乙烯的静态结构的模型，该取向聚乙烯由取向原纤维组成，而取向原纤维是由微原纤维束构建的。另一方面，发现变形是由微原纤维的滑移而不是原纤维的滑移介导的。在微原纤中，聚合物链在结晶区和非晶区均高度取向。当拉伸超过自然拉伸比时，主要发生微原纤维彼此之间的滑移。层间非晶层的厚度仅略有增加。由于微原纤间的聚合物片段被拉紧，微原纤之间的耦合力在拉伸期间增加，因此越来越阻碍微原纤的进一步滑动，最终导致原纤的滑动。
Synchrotron small angle X-ray scattering was used to study the deformation mechanism of high-density polyethylene that was stretched beyond the natural draw ratio. New insight into the cooperative deformational behavior being mediated via slippage of micro-fibrils was gained. The scattering data confirm on the one hand the model proposed by Peterlin on the static structure of oriented polyethylene being composed of oriented fibrils, which are built by bundles of micro-fibrils. On the other hand it was found that deformation is mediated by the slippage of the micro-fibrils and not the slippage of the fibrils. In the micro-fibrils, the polymer chains are highly oriented both in the crystalline and in the amorphous regions. When stretching beyond the natural draw ratio mainly slippage of micro-fibrils past each other takes place. The thickness of the interlamellar amorphous layers increases only slightly. The coupling force between micro-fibrils increases during stretching due to inter-microfibrillar polymer segments being stretched taut thus increasingly impeding further sliding of the micro-fibrils leading finally to slippage of the fibrils.