New Insights into Lamellar Structure Development and SAXS/WAXD Sequence Appearance during Uniaxial Stretching of Amorphous Poly(ethylene terephthalate) above Glass Transition Temperature
New Insights into Lamellar Structure Development and SAXS/WAXD Sequence Appearance during Uniaxial Stretching of Amorphous Poly(ethylene terephthalate) above Glass Transition Temperature
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DOI：
10.1021/ma702554t
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发表时间：
2008-03
期刊：
影响因子：
5.5
通讯作者：
D. Kawakami;C. Burger;S. Ran;C. Ávila‐Orta;I. Šics;B. Chu;S. Chiao;B. Hsiao;T. Kikutani
中科院分区：
文献类型：
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作者：
D. Kawakami;C. Burger;S. Ran;C. Ávila‐Orta;I. Šics;B. Chu;S. Chiao;B. Hsiao;T. Kikutani
采用同步辐射小角X射线散射（SAXS）和广角X射线衍射（WAXD）技术对非晶态聚对苯二甲酸乙二酯（PET）在玻璃化转变温度以上30 °C的单轴拉伸过程中的结构形成进行了原位研究。三个主要的变形引起的结构转变得到证实。(1)在小应变下，施加的载荷最初增加，但之后趋于平稳。WAXD观察到零星的各向同性结晶，没有择优取向，而SAXS没有看到分级结构。(2)在中等应变下，发生应变硬化。虽然WAXD显示了各向同性结晶的持续发展，SAXS表明形成了层状结构以及大规模的纤维状结构域。这种行为是不一致的shish-kebab或spinodal辅助结构形成的机制。相反，它可以解释为流动诱导的晶体和非晶相的分层通过激光。
An in situ study of structure formation in amorphous poly(ethylene terephthalate) (PET) during uniaxial stretching at a temperature 30 °C above glass transition temperature was carried out using synchrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) techniques. Three major deformation-induced structure transitions were confirmed. (1) At small strains, the applied load increased initially but leveled off afterward. Sporadic isotropic crystallization without preferred orientation was observed by WAXD, where no hierarchical structure was seen by SAXS. (2) At intermediate strains, strain hardening took place. Although WAXD showed persistent progression of isotropic crystallization, SAXS indicated formation of a layered structure as well as a fibrillar domain in large scale. This behavior is not consistent with the mechanisms for shish-kebab or spinodal-assisted structure formation. Instead, it can be explained by flow-induced demixing of crystal and amorphous phases through la...