Vibrational Spectra of Polytetrafluoroethylene: Effects of Temperature and Pressure
Vibrational Spectra of Polytetrafluoroethylene: Effects of Temperature and Pressure
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DOI：
10.1063/1.1724924
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发表时间：
1964-05
影响因子：
4.4
通讯作者：
R. G. Brown
中科院分区：
文献类型：
--
作者：
R. G. Brown
研究了聚四氟乙烯在低压和常温下的红外光谱随温度的变化规律。625 ~ 640 cm-1区域吸收的温度依赖性与625 cm-1区域吸收是由于产生能e≈0.05 eV的缺陷引起的一致。对分子螺旋螺距反转所带来的能量增加的计算支持了这一观点。在T≈100°K时，在700 ~ 1700 cm-1区域存在一些在环境温度下不明显的可分辨波段。当温度为600°K时，发现光谱与文献报道有显著差异。施加6kbar压力会导致640和1210 cm-1处的吸收显著降低。随着压力的变化支持了只有在高压下才存在的相中的分子的平面构象的建议。拉曼光谱在733 cm-1和1378 cm-1处显示出谱线，这与基于…
The infrared spectrum of polytetrafluoroethylene was investigated as a function of temperature at low pressure, and as a function of pressure at ambient temperature. The temperature dependence of absorption in the region 625–640 cm—1 is consistent with the suggestion that the band at 625 cm—1 is due to a defect with creation energy e≈0.05 eV. A calculation of the energy increase accompanying reversal of the pitch of the molecular helix supports this suggestion. At T≈100°K, there are resolved a number of bands in the region 700–1700 cm—1 that are not apparent at ambient temperature. For T>600°K, the spectrum was found to be significantly different from a report in the literature. Application of pressure p>6 kbar results in significantly reduced absorption at 640 and 1210 cm—1. The changes with pressure support the suggestion of a planar conformation of the molecule in a phase existing only at high pressure. The Raman spectrum exhibited lines at 733 and 1378 cm—1, in good agreement with predictions based up...