Elasticity Reinforcement in Propylene–Ethylene Random Copolymer Stretched at Elevated Temperature in Large Deformation Regime
Elasticity Reinforcement in Propylene–Ethylene Random Copolymer Stretched at Elevated Temperature in Large Deformation Regime
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DOI：
10.1021/acs.macromol.5b02585
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发表时间：
2016-01
期刊：
影响因子：
5.5
通讯作者：
Jiayi Zhao;Y. Sun;Yongfeng Men
中科院分区：
文献类型：
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作者：
Jiayi Zhao;Y. Sun;Yongfeng Men
用原位小角和广角X射线散射技术研究了乙烯含量为12mol%的无规丙烯-乙烯共聚物在室温和63 °C下的拉伸变形行为。在这两种条件下，变形机制从滑移的结晶片层块转变为拉伸诱导熔化和再结晶过程在约0.9的临界应变。半结晶聚合物拉伸变形的临界应变通常标志着弹性应变平台值的开始。进一步的拉伸导致塑性变形的增加，这仅仅是由于原纤化。然而，当样品在63 °C下拉伸时，在大于1.3的应变下观察到特殊的弹性增强。广角X射线散射结果表明，在此应变为1.3的原无取向的晶体的原纤化完成，使进一步拉伸导致一个相当稳定的缠结网络嵌入的原纤，具有高弹性变形。
Tensile deformation behavior of a random propylene–ethylene copolymer with 12 mol % ethylene counits at room temperature and 63 °C was investigated using the in situ small and wide-angle X-ray scattering techniques. Under both conditions, the deformation mechanism changed from slip of crystalline lamellar blocks to stretching induced melting and recrystallization process at a critical strain of about 0.9. This critical strain in tensile deformation of semicrystalline polymers normally marks the starting of plateau value of elastic strain. Further stretching leads to increase of plastic deformation only due to the fibrillation. However, a peculiar elasticity reinforcement was observed at strain larger than 1.3 when the sample was stretched at 63 °C. Wide angle X-ray scattering results indicate that at this strain of 1.3 fibrillation of the originally unoriented crystals finished so that further stretching leads to a deformation of a rather stable entangled network embedded by fibrils that possesses high el...