Thermotropic copolyesters from methylhydroquinone,4,4'-dipbenyldicarboxylic acid and 2,6-naphthalenedicarboxylic acid

Abstract

Copolyesters from methylhydroquinone (Me-HQ), 4,4'-diphenyldicarboxylic acid (BB) and 2,6-naphthalenedicarboxylic acid (NDA) with various molar ratios were prepared and their thermal and mechanical properties were investigated. The modulus of as-spun fibres from Me-HQ/BB/NDA tends to increase as the orientation function of the nematic domains (F value) increases. As-spun fibre from a polymer with a molar ratio m/n=92.5/7.5 showed the highest modulus of 112GPa at F=0,91. However, the injection-moulded specimens did not show the same tendency and the highest modulus of 44 GPa was observed at the lowest F value of 0.56. From these results, it is assumed that the F value plays a predominant role in determining the modulus of the as-spun fibre, whereas other factors, such as rigidity of polymer chain. packing density of polymer chains and melt flowability, determine the modulus of the injection-moulded specimens.

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References

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Kobunshi Ronbunshu

43 261-261