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Thermotropic nematic polyesters

Blumstein, R. B., Stickles, E. M., Gauthier, M. M., Blmnstein, A., and Vohno, R, Influence of molecular weight on phase transitions and alignment of a thermotropic nematic polyester, Macwmolecules, 17,177-183 (1984). [Pg.316]

ORDER AND ODD-EVEN EFFECTS IN THERMOTROPIC NEMATIC POLYESTERS... [Pg.129]

Aromatic polyesters undoubtedly represent the most important class of thermotropic nematics. Fully aromatic rod-hke homopolymers such as poly(p-oxybenzoate) or poly (p-phenylene terephthalate) melt at temperatures which are too high to form a stable nematic mesophase. However if the regular chemical structure of the homopolymer is disrupted, the melting temperature is reduced and it is possible to obtain thermotropic nematics. ... [Pg.495]

Li MH, Brulet A, Cotton JP, Davidson P, Strazielle C, Keller P (1994) Study of the chain coirformation of thermotropic nematic main chain polyesters. J Phys II France 4 1843... [Pg.48]

Phase transitions in thermotropic nematic and cholesteric main chain polyesters were investigated by polarizing microscopy and differential scanning calorimetry ... [Pg.239]

Thermotropic liquid crystals, 15 86-98 bent-core, 15 98 discotic phases of, 15 96 frustrated phases of, 15 94-96 metallomesogens, 15 97 nematic liquid crystals, 15 86-92 smectic liquid crystals, 15 92-94 Thermotropic mesophases, 20 79 Thermotropic polycarbonates, 19 804 Thermotropic polyesters, liquid-crystalline, 20 34... [Pg.944]

A selection of monosubstituted and disub-stituted poly-(/ -phenylene-terephthalate)s is compared in Table 2. Poly(p-phenylene-terephthalate)s with methyl, methoxy, chlo-ro, or bromo substituents on either the hy-droquinone or the terephthalic acid moiety exhibit melting temperatures of 350 °C or higher. Thermotropic liquid crystalline behavior is observed in these samples, although it is in the range of thermal decomposition. A comparison of the mono- and diphenyl substituted polyesters reveals an important trend. The monosubstituted poly-(p-phenylene-terephthalate) with the phenyl substituent in the hydroquinone moiety melts at 346 °C, also forming a nematic melt up to a clearing temperature of... [Pg.19]

A.Blumstein, S.Vilasagar, S.Ponrathnam, S.B.Clough, and R.B. Blumstein, Nematic and cholesteric thermotropic polyesters with azoxybenzene mesogenic units and flexible spacers in the main chain, J.Polym.Sci., Polym.Phys.Ed. 20 877 (1982). [Pg.281]

Thermotropic polyesters are melt-spun from the nematic phase and orient easily in an elongational flow field (moderate drawdowns/forces are sufficient). In the fiber case, highly oriented fibers form easily with an initial modulus close to theory—typical values range from about 70 to 150 GPa. Ward [46] has shown that the tensile modulus may be described by an aggregate model, i.e., the modulus is a function of the inherent chain modulus, the molecular chain orientation, and the shear modulus (which described the stress transfer between chains). The tensile strength of LCP fibers follows the prediction of the lag-shear model [47]. Both the aggregate model and the lag shear model treat the LCP as though it... [Pg.16]

All of the present polyesters are thermotropic and formed nematic liquid crystalline phase upon melting. The isotropization temperatures, Ti, of the ordered sequence... [Pg.291]

R B Blumstein. Nematic and Cholesteric Thermotropic Polyesters with Azoxybenzene Mesogenic Units and Flexible Spacers in the Main Chain. J.Poly.Sci Poly.Phys. 20 877 (1982). [Pg.368]

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