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Segmental motions and associated dynamic mechanical thermal properties of a series of copolymers based on poly(hexamethylene terephthalate) and poly(1,4-cyclohexylenedimethylene terephthalate)

Segmental motions and associated dynamic mechanical thermal properties of a series of copolymers... Abstract The dynamic mechanical thermal properties of poly(hexamethylene terephthalate) (PHT), poly(1,4-cyclohexylenedimethylene terephthalate) (PCT) and their P(HT-co-CT) random copolymers in the amorphous state were examined as a function of temperature and frequency. All the samples exhibited two main relaxation processes in the plot of tan δ versus temperature: the primary α-relaxation associated with the glass transition and the secondary β-relaxation attributed to the local segmental motions of mostly cyclohexylene rings for PCT and to cooperative motions of methylene, carboxyl, and phenylene groups for PHT. Both α- and β-relaxation temperatures increased with increasing CT content. The activation energy of the α-relaxation increased with increasing CT content, whereas that of the β-relaxation decreased. The sub-glassy secondary β-relaxation processes of PCT and PHT were investigated in terms of the cooperativity of main-chain segmental motions. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png "Macromolecular Research" Springer Journals

Segmental motions and associated dynamic mechanical thermal properties of a series of copolymers based on poly(hexamethylene terephthalate) and poly(1,4-cyclohexylenedimethylene terephthalate)

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References (41)

Publisher
Springer Journals
Copyright
2006 The Polymer Society of Korea and Springer
ISSN
1598-5032
eISSN
2092-7673
DOI
10.1007/BF03219104
Publisher site
See Article on Publisher Site

Abstract

Abstract The dynamic mechanical thermal properties of poly(hexamethylene terephthalate) (PHT), poly(1,4-cyclohexylenedimethylene terephthalate) (PCT) and their P(HT-co-CT) random copolymers in the amorphous state were examined as a function of temperature and frequency. All the samples exhibited two main relaxation processes in the plot of tan δ versus temperature: the primary α-relaxation associated with the glass transition and the secondary β-relaxation attributed to the local segmental motions of mostly cyclohexylene rings for PCT and to cooperative motions of methylene, carboxyl, and phenylene groups for PHT. Both α- and β-relaxation temperatures increased with increasing CT content. The activation energy of the α-relaxation increased with increasing CT content, whereas that of the β-relaxation decreased. The sub-glassy secondary β-relaxation processes of PCT and PHT were investigated in terms of the cooperativity of main-chain segmental motions.

Journal

"Macromolecular Research"Springer Journals

Published: Aug 1, 2006

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