Relaxation processes in liquid crystalline polymers

The dynamic mechanical properties of these oriented HBA/HNA copolymers have been studied by Yoon and Jaffe [35], Blundell and Buekingham [36] and Ward and co-workers [37]. It is of particular interest to eompare different compositions based on HBA and HNA only, with two other eopolymers that incorporate 

4-Hydroxybenzoic acid HNA, 2-Hydroxy 6-naphthoic acid TA, terephthalic acid DHN, 2,6 dihydroxynaphthalene BP, 4,4 biphenyldiol. 

The y relaxation is associated with the motion of phenylene groups, and this is shown most clearly by comparison of the dielectric relaxations for the CO 73/27 and CO 30/70 copolymers. These results suggest that the carbonyl group is strongly coupled to the aromatic ring to which it is attached, so that in this case there is a direct correlation between the mechanical and dielectric relaxations. 

There are several conclusions to be made regarding the relaxation behaviour of these thermotropic liquid crystalline polymers that have broad implications. First, 

Heijboer, X, Physics of Non-Crystalline Solids, North-Holland, Amsterdam, 1965, p. 231. 

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