A Three Dimensionally Oriented Texture for Poly(tetrafluoro-p-xylene)
A Three Dimensionally Oriented Texture for Poly(tetrafluoro-p-xylene)
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聚四氟对二甲苯的三维定向织构
DOI：
10.1021/ma981030d
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
S. Chvalun
中科院分区：
文献类型：
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作者：
J. Blackwell;Soo Young Park;S. Chvalun
气相沉积法制备的聚(α，α，α‘，α’-四氟对二甲苯)薄膜具有高度的结晶性和单面取向。在350°C拉伸×10时，当链平行于拉伸方向排列时，该取向保持不变，从而产生三维取向的晶体。通过控制样品的旋转和倾斜来分辨35个X射线反射，这些反射可以由一个三斜晶胞来指示，其尺寸为a=5.36A，b=5.92A，c=6.57A(链轴重复)，α=97°，β=63.1°，γ=73.1°，包含一个单体单元。分子力学支持−CF2−CF2键的跨平面构象，该构象与相邻苯基成90°倾斜，导致纤维重复与观察到的相同。堆积分析指出了一种苯基近似垂直于Ac平面的结构，这给出了观测到的结构幅度与计算的结构幅度(R…
Films of poly(α,α,α‘,α‘-tetrafluoro-p-xylylene) prepared by vapor deposition polymerization are highly crystalline and have uniplanar orientation. This orientation is maintained on drawing ×10 at 350 °C, when the chains become aligned parallel to the direction of draw, leading to a texture of three-dimensionally oriented crystals. Thirty-five X-ray reflections are resolved by controlled rotation and tilting of the drawn specimen, and these can be indexed by a triclinic unit cell with dimensions a = 5.36 A, b = 5.92 A, c = 6.57 A (chain axis repeat), α = 97.0°, β = 63.1°, and γ = 73.1°, containing one monomer unit. Molecular mechanics favors a trans-planar conformation for the −CF2−CF2 linkage which is inclined at 90° to the adjacent phenyl groups, leading to a fiber repeat that is equal to that observed. Packing analyses point to a structure in which the phenyl groups are approximately perpendicular to the ac plane, and this gives good agreement between the observed and calculated structure amplitudes (R ...