Dynamic mechanical and dielectric relaxations in liquid crystalline copolymers formed from hydroxynaphthoic acid, terephthalic acid and p-aminophenol

Dynamic mechanical and dielectric measurements were carried out in the temperature range −120 to 160°C on nematic random copolymers formed from 60% hydroxynaphthoic acid, 20% terephthalic acid and 20% p-aminophenol. Only two relaxation transitions were observed both mechanically and dielectrically:...

Full description

Saved in:
Bibliographic Details
Published in:Materials letters 1992-05, Vol.13 (6), p.312-317
Main Authors: Jawad, S.Abdul, Alhaj-Mohammad, M.H.
Format: Article
Language:English
Subjects:
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Dielectric loss and relaxation
Dielectric properties of solids and liquids
Dielectrics, piezoelectrics, and ferroelectrics and their properties
Exact sciences and technology
Physics
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Dynamic mechanical and dielectric measurements were carried out in the temperature range −120 to 160°C on nematic random copolymers formed from 60% hydroxynaphthoic acid, 20% terephthalic acid and 20% p-aminophenol. Only two relaxation transitions were observed both mechanically and dielectrically: the β and α relaxations. The virtual absence of the low-temperature γ relaxation is attributed to the existence of hydrogen bonding anticipated in this copolymer. The appearance of a pronounced dielectric α relaxation confirms that some electric dipoles were inactive at low temperatures and become active when hydrogen bonds are broken at high temperatures.
ISSN:0167-577X
1873-4979
DOI:10.1016/0167-577X(92)90059-S