Nanostructure and crystallization phenomena in multilayered films of alternating iPP and PA6 semicrystalline polymers
Nanostructure and crystallization phenomena in multilayered films of alternating iPP and PA6 semicrystalline polymers
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iPP 和 PA6 半晶聚合物交替多层膜的纳米结构和结晶现象
DOI：
10.1016/j.eurpolymj.2011.10.003
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发表时间：
2012
影响因子：
6
通讯作者：
B.S. Hsiao
中科院分区：
文献类型：
--
作者：
F. Ania;F.J. Baltá-Calleja;A. Flores;G.H. Michler;S. Scholtyssek;D. Khariwala;A. Hiltner;E. Baer;L. Rong;B.S. Hsiao
目前的工作涉及两种交替不混溶半结晶聚合物：等规聚丙烯 (iPP) 和聚酰胺 6 (PA6) 的多层系统的晶体形态和纳米结构的研究。采用多层共挤的方法制备体积比为70/30的薄膜。与之前使用半结晶/非晶和非晶/非晶纳米层系统进行的实验相反，所研究的 iPP/PA6 薄膜在 USAXS 图案中没有表现出明确定义的最大值。这一结果解释了不规则的层状结构，并通过 TEM 图像进一步证实。然而，这种层状组装仍然影响两种聚合物的结晶行为。一方面，PA6 在多层材料内的结晶受到显着阻碍，其弱散射强度证明了这一点。作为温度函数的实时研究无疑检测到与高于 iPP 熔化温度的 PA6 相关的 WAXS 峰和 SAXS 最大值的存在。室温 AFM 研究还证实了 PA6 层内晶体结构的存在。另一方面，室温下的 SAXS 和 WAXS 测量揭示了 iPP 层内出现了定向层状形态，围绕垂直于层表面的轴具有单轴对称性。结果表明，结晶分子链主要平行于形成边缘片层的层表面放置。此外，X射线散射结果与两个片晶群的出现一致，两个片晶群都是边上且彼此垂直，与AFM观察到的交叉影线形貌一致。
The present work is concerned with the study of the crystalline morphology and the nanostructure of a multilayered system of two alternating immiscible semicrystalline polymers: isotactic polypropylene (iPP) and polyamide 6 (PA6). Films with a volume ratio of 70/30 were prepared by means of layer multiplying coextrusion. Contrary to previous experiments, performed with semicrystalline/amorphous and amorphous/amorphous nanolayered systems, the studied iPP/PA6 film does not exhibit a well defined maximum in the USAXS patterns. This result accounts for an irregular layered structure, as further confirmed by means of TEM images. Nevertheless, such a layered assembly still influences the crystallization behaviour of both constituent polymers. On the one hand, the crystallization of PA6 within the multilayered material is substantially hindered as evidenced by its weak scattering intensity. Real time studies as a function of temperature undoubtedly detect the presence of a WAXS peak and a SAXS maximum associated to PA6 above the melting temperature of iPP. Room temperature AFM studies also confirm the occurrence of crystalline structures within the PA6 layers. On the other hand, SAXS and WAXS measurements at room temperature reveal the occurrence of an oriented lamellar morphology within the iPP layers bearing uniaxial symmetry around an axis perpendicular to the layers surface. Results show that the crystalline molecular chains are placed mainly parallel to the layer surfaces forming edge-on lamellae. Moreover, X-ray scattering results are in agreement with the occurrence of two populations of lamellae, both edge-on and perpendicular to each other, in agreement with the crosshatched morphology observed by AFM.
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影响因子：
3.2
作者：
Dooley, J;Hyun, KS;Hughes, K
通讯作者：
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DOI：
--
发表时间：
1993
期刊：
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DOI：
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发表时间：
2008
期刊：
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DOI：
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发表时间：
2005
期刊：
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作者：
R. Adhikari;W. Lebek;R. Godehardt;S. Henning;G. Michler;E. Baer;A. Hiltner
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影响因子：
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作者：
Liu, Yi;Cui, Li;Fong, Hao
通讯作者：
Fong, Hao