Flow birefringence and conformational characteristics of molecules of para-and meta-isomers of polyoxyphenyl-benzoxazoleterephthalamides

Several series of polyester imides (PEIs) were prepared by melt polycondensation of trimellitimidobenzoic acid and acetylated, substituted hydroquinones as well as by solution polycondensation of corresponding dichlorides with hydroquinones. The influence of either phenyl‐ or tert‐butyl substituents at the hydroquinone unit on the hydrodynamic (diffusion and viscometry) and optical [flow (FB) and electrical (EB) birefringence] properties of solutions of these PEIs were investigated. Independent methods for quantitative evaluation of the length of the statistical Kuhn segment A gave values of 14.5 nm (translational friction and electrical birefringence) and 12.0 nm (flow birefringence), respectively. The equilibrium rigidity of PEIs with phenyl and tert‐butyl lateral substituents at the para‐aromatic chain fragment was comparable. Conformational properties of the PEIs were analyzed, and the conjugation energies of the ester and amide groups for para‐aromatic polyesters, PEIs, and structurally similar polyamidobenzoxazoles and polyamidobenzimidazoles were compared. The introduction of the phthalimide ring leads to a decrease of conjugation energy and deviation of the ester group from coplanarity. The Kuhn segment values obtained were useful for calculations of phase diagrams of semiflexible segmented block copolymers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 12–24, 2004

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Orientational–deformational nature of flow birefringence in solutions of rigid‐chain polymers

Pogodina

1993

J Polym Sci B Polym Phys

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The orientational–deformational nature of flow birefringence (FB) in solutions of rigid‐chain polymers is confirmed experimentally. The possibility of a direct determination of the internal viscosity parameter by the dependence of the FB relaxation time on the solvent viscosity is demonstrated. Indirect manifestation of internal viscosity in the FB relaxation time is confirmed by the dependence of the form factor on the degree of coiling. © 1993 John Wiley & Sons, Inc.

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Flow birefringence and conformational characteristics of molecules of para-and meta-isomers of polyoxyphenyl-benzoxazoleterephthalamides

Cited by 7 publications

References 3 publications

Anisotropy of Segments and Monomer Units of Polymer Molecules

Anisotropy of Segments and Monomer Units of Polymer Molecules

Conformational properties of macromolecules of heterocyclic polyester imides in dilute dichloroacetic acid solutions

Orientational–deformational nature of flow birefringence in solutions of rigid‐chain polymers

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