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Liquid crystal polymers 23. Steric and polar effects of large substituents in thermotropic aromatic polyesters with decamethylene spacers
Author(s) -
Furukawa Akira,
Lenz Robert W.
Publication year - 1986
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19860020103
Subject(s) - thermotropic crystal , substituent , steric effects , liquid crystal , mesogen , polyester , chemistry , polymer chemistry , polymer , triclinic crystal system , crystallography , hydroquinone , materials science , organic chemistry , crystal structure , liquid crystalline , optoelectronics
A series of thermotropic aromatic polyesters based on a triad ester mesogenic unit containing an arylsulfonyl substituted hydroquinone group and a decamethylene spacer group was prepared. The large arylsulfonyl substituent was substituted in the para‐position with either electron donating or accepting groups to study the effect of steric and polar interactions on the thermal transitions of these polymers and on the thermodynamic parameters of their isotropization transitions. All polymers formed nematic melts, and a regular decrease in T 1 , ΔH 1 and ΔS 1 was observed with increasing molecular radius of the substituted hydroquinone group. However, a polarity or polarizability effect was superimposed on these relationships. Model compounds containing the same aromatic ester triad were prepared and their thermotropic properties were compared to those of the polymers. Essentially identical effects were observed for both.