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A comparative dielectric study on the molecular dynamics of the liquid crystalline and the amorphous state of copolyesters

✍ Scribed by Oscar Ahumada; Tiberio A. Ezquerra; Aurora Nogales; Francisco J. Baltà-Calleja; Hans G. Zachmann

Publisher
John Wiley and Sons
Year
1995
Tongue
English
Weight
310 KB
Volume
16
Category
Article
ISSN
1022-1336

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✦ Synopsis

Abstract

The complex dielectric permittivity has been measured in the 10^3^−10^6^ Hz frequency range for selected random copolyesters of poly(ethylene terephthalate). The variation of the dielectric properties with temperature has been qualitatively related mainly to two processes. The α relaxation, which is associated with the glass transition, has been shown to be dependent on the molecular order of the systems. The β relaxation process has been assigned to local motions of the ester groups attached to both sides of the aromatic rings. The β process is also shown to exhibit a dependence on molecular order.

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