Dynamic birefringence in solutions of poly (naphthoyleneimide benzimidazole) in different stages of hydrolytic thermal degradation

Lavrenko, P. N.; Andreeva, K. A.; Strelina, I. A.

doi:10.1007/bf02547543

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“…b Values calculated by eq 15. c Formula weight for model compound C 12 H 6 NO 2 −C 7 H 4 N 2 −C 6 H 4 −C 12 H 6 NO 2 . d Samples obtained by the thermal hydrolysis of the PNI sample in solution as described previously …”

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confidence: 99%

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Diffusion and Flow Birefringence of Poly(naphthoyleneimide benzimidazole) in Concentrated Sulfuric Acid

Lavrenko

Pogodina

1998

Macromolecules

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The effect of changes in chemical structure on the equilibrium and kinetic behavior is examined for fully cyclic poly(naphthoyleneimide benzimidazole) (PNI) molecules in dilute solution in 96% sulfuric acid. With this aim, hydrodynamic and dynamo-optical properties were analyzed over a wide range of molecular weight from 6.7 × 10 3 to 2.5 × 10. 5 The M dependence of the translational diffusion coefficient, D, the shear optical coefficient, ∆n/∆τ, the intrinsic orientation of the macromolecules in the flow, [ /g], and the intrinsic viscosity, [η], were established as well as the macromolecule conformation. Results thus obtained indicate the rigid-chain behavior of the PNI molecules. From their comparison with similar data obtained earlier for poly(amide benzimidazole) the conclusion was made that the exclusion of physical mechanisms of the chain flexibility due to the amide group leads to a significantly higher equilibrium rigidity of the macromolecule. At the same time, the comparison of the flow birefringence relaxation time with the viscometric data indicates the intramolecular motions that include a large-scale deformation of the PNI chain increasing with the molecular weight.

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Section: Resultsmentioning

confidence: 99%

“…Dynamo-Optical Properties of the PNI Samples a Samples obtained by the thermal hydrolysis of the PNI sample in solution as described previously 32. …”

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confidence: 99%