Substituted-HQs/BB polyarylates

Table 19.3 Thermal properties and moduli of substituted-HQs/BB polyarylates [19]. From Inoue, T. and Tabata, N., Mol. Cryst. Liq. Cryst., 254, 417-428 (1994), and reproduced with permission of Gordon and Breach (Taylor and Francis) Publishers...

The polyarylates were prepared from substituted HQ diacetates, substituted PECs and BB by melt polymerization at 250-400 °C. The pressure was gradually reduced to 1 torr as the polymerization proceeded. 

Therefore, we expected that the polyarylates synthesized from substituted HQs and BB would show higher stabilities of the liquid crystalline state and higher moduli than those produced from substituted HQs and substituted PEC. 

The Tm values of the poly(alkylene-4,4 -diphenyldicarboxylate)s are much higher than those of the poly(alkylene terephthalate)s. Therefore, as polyarylates derived from substituted HQs and BB seemed to have higher Tms, the, LCPs derived from BB and alkylene glycols with higher carbon numbers have been investigated [24],... 

However, in spite of the higher rigidity of the polymer chains, many pol-yarylates derived from substituted HQs and BB exhibited liquid crystallinity and lower Tms when compared to the polyarylates derived from substituted HQs and TA. 

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