Studies on the crystallinity of poly(tetrafluoroethylene)
Studies on the crystallinity of poly(tetrafluoroethylene)
This study was conducted to gain insight into the phenomenon 'crystallinity' in the polymer poly(tetrafluoroethylene). Several routinely used techniques for determining the crystallinity were employed and an investigation of the feasibility of determining crystallinity with Raman spectroscopy was carried out. The results of wide-angle x-ray scattering, infrared spectroscopy, differential scanning calorimetry and density measurement on melt-quenched samples were compared to check these methods for consistency before changes in the Raman spectra were systematically correlated with the crystallinity as derived from these methods.
An increasing band 'tailing' of the Raman band at Δν = 1380 cm-1 (CF2 symmetric stretching fundamental) was identified as the most marked effect of decreased crystallinity and a novel method for quantifying this spectral feature has been devised. It was found that the quantified band 'tailing' can serve as a measure for the crystallinity and that all methods including Raman give consistent results. On the basis of the findings a model for poly(tetrafluoroethylene) is proposed which comprises, dependent on the molecular weight, either two or three different structural phases.
University of Southampton
1994
Lehnert, Ralph Jürgen
(1994)
Studies on the crystallinity of poly(tetrafluoroethylene).
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
This study was conducted to gain insight into the phenomenon 'crystallinity' in the polymer poly(tetrafluoroethylene). Several routinely used techniques for determining the crystallinity were employed and an investigation of the feasibility of determining crystallinity with Raman spectroscopy was carried out. The results of wide-angle x-ray scattering, infrared spectroscopy, differential scanning calorimetry and density measurement on melt-quenched samples were compared to check these methods for consistency before changes in the Raman spectra were systematically correlated with the crystallinity as derived from these methods.
An increasing band 'tailing' of the Raman band at Δν = 1380 cm-1 (CF2 symmetric stretching fundamental) was identified as the most marked effect of decreased crystallinity and a novel method for quantifying this spectral feature has been devised. It was found that the quantified band 'tailing' can serve as a measure for the crystallinity and that all methods including Raman give consistent results. On the basis of the findings a model for poly(tetrafluoroethylene) is proposed which comprises, dependent on the molecular weight, either two or three different structural phases.
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Published date: 1994
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Local EPrints ID: 458540
URI: http://eprints.soton.ac.uk/id/eprint/458540
PURE UUID: 26c8fca2-06af-44ad-897a-7f6235dee9f3
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Date deposited: 04 Jul 2022 16:51
Last modified: 04 Jul 2022 16:51
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Author:
Ralph Jürgen Lehnert
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