Fully aromatic polyesters have been prepared by esterification reaction between hydroquinon derivatives and terephthalic acid. These polymers as anticipated displayed thermotropic liquid crystal tehaviour, which was evidenced by DSC method. Also the TGA results revealed that these polymers are fairly thermally stable up to the temperature of 450℃ and beyond that the scission of ester linkage had occurred. Comparisons were made from the synthesis point of view between the fully aromatic polyester and the conventional polyethylene terephthalate. These two condensation reactions appeared similar with exception of their reaction temperatures, i. e., the latter took place at temperatures 50 to 60℃ lower. Also, the conventional type differed from the liquid crystal type in melt viscosities particularly around the temperatures where the condensation comes to completion. The conventional polyester exhibits a Newtonian behavior turns into pseudoplasticity. For the aromatic types, on the other hand, a pseudoplastic behavior sets in earlier, say, at a shear rate of 5 sec^-1 and its flow index is much lower than that of the conventional polyester. Thus at shear rates imposed by the mixing methods conventionally in practice at present, the melt viscosities of liquid crystal polymers such as ones treated herein, can be lowered significantly in comparision to those of non-liquid crystalline polymers. This supports strongly the possibility of employing conventional process equipment for the synthesis and processing of new aromatic polymer.

히드로퀴논 유도체와 테레프탈산의 에스터 반응에 의해 전방향족 폴리에스터를 합성하였다. DSC와 TGA에 의한 결과를 고찰하면 이들 고분자는 310∼320℃ 범위에서 액정을 형성하고 450℃까지는 안정하며 485℃에서 에스테르결합의 분해가 일어남을 보여주었다. 한편 재래식의 폴리에틸렌 테레프탈레이트와 합성측면에서 비교해보면, 양자의 중합반응은 현상학적으로는 유사하고 반응 온도만 50∼60℃ 정도 낮다고 볼 수 있다. 그리고 중합 온도에서의 용융점도를 조사한 결과 전방향족 시료는 5S^-1까지 newtonian 성질을 보이나 그 이상에서는 pseudoplaciticity를 나타내었다. 반면 재래식 폴리에스테르는 100S^-1 이후에서 기울기가 완만한 pseudoplaciticity를 보임으로, 교반속도에 상응하는 shear Rate에서는 오히려 액정성 폴리에스테르의 점도가 더 낮아지기 때문에 이들의 공업적 합성을 위한 기존 설비의 이용 가능성을 시사해주었다.