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Vibrational spectroscopic studies of the molecular structure of some polymer systems

Vibrational spectroscopic studies of the molecular structure of some polymer systems
Vibrational spectroscopic studies of the molecular structure of some polymer systems

Three studies of polymer systems have been carried out using vibrational spectroscopic techniques. These three projects are totally separate in background, but use related techniques which come under the umbrella of vibrational spectroscopy.

An investigation of joints in high density polyethylene by means of low frequency Raman spectroscopy was carried out. The frequency of the longitudinal acoustic mode of polyethylene was used as a way of measuring the lamellar thickness of the material in the weld. It suggested that the most important factor in the welding process is the crystallization temperature of the melt. There is no evidence that the pre-melt morphology or the morphology of the adjacent bulk material affects the morphology of the weld.

Fourier Transform Raman spectroscopy was used to study the crystallization process in isotactic polystyrene. Although it was not possible to improve on the maximum crystallinity values previously reported in the literature, the use of a low temperature cell enabled a band due to material in the crystal structure to be distinguished from one due to material in the amorphous regions. It is suggested that the main contributory factor to the low crystallinity of isotactic polystyrene is the slow rate of formation of the helix chain structure.

A new infrared method of studying thick polymer films was evaluated. The technique makes use of variable angle specular reflection spectroscopy with polarized radiation. It is concluded that the use of transflectance techniques, where the sample is mounted on a mirror support, does not offer any advantages over traditional transmission methods. The use of specular reflection, where the sample is mounted on an infrared absorbent material, is more promising, offering the prospect of measuring the degree of orientation in the plane of the film and possibly through the thickness of the film as well.

University of Southampton
Wesley, Ian John
Wesley, Ian John

Wesley, Ian John (1994) Vibrational spectroscopic studies of the molecular structure of some polymer systems. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

Three studies of polymer systems have been carried out using vibrational spectroscopic techniques. These three projects are totally separate in background, but use related techniques which come under the umbrella of vibrational spectroscopy.

An investigation of joints in high density polyethylene by means of low frequency Raman spectroscopy was carried out. The frequency of the longitudinal acoustic mode of polyethylene was used as a way of measuring the lamellar thickness of the material in the weld. It suggested that the most important factor in the welding process is the crystallization temperature of the melt. There is no evidence that the pre-melt morphology or the morphology of the adjacent bulk material affects the morphology of the weld.

Fourier Transform Raman spectroscopy was used to study the crystallization process in isotactic polystyrene. Although it was not possible to improve on the maximum crystallinity values previously reported in the literature, the use of a low temperature cell enabled a band due to material in the crystal structure to be distinguished from one due to material in the amorphous regions. It is suggested that the main contributory factor to the low crystallinity of isotactic polystyrene is the slow rate of formation of the helix chain structure.

A new infrared method of studying thick polymer films was evaluated. The technique makes use of variable angle specular reflection spectroscopy with polarized radiation. It is concluded that the use of transflectance techniques, where the sample is mounted on a mirror support, does not offer any advantages over traditional transmission methods. The use of specular reflection, where the sample is mounted on an infrared absorbent material, is more promising, offering the prospect of measuring the degree of orientation in the plane of the film and possibly through the thickness of the film as well.

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Published date: 1994

Identifiers

Local EPrints ID: 462843
URI: http://eprints.soton.ac.uk/id/eprint/462843
PURE UUID: 9891d5a8-505b-4e19-8507-978646c23d34

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Date deposited: 04 Jul 2022 20:14
Last modified: 04 Jul 2022 20:14

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Author: Ian John Wesley

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