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Influence de la température et de la nature du solvant sur les dimensions du poly-p-bromostyrène. Observation d'une transition conformationnelle by Karayannidis, Petros ;Dondos, Anastasios is a Chemistry article available to read on EtoBox.

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## Abstract We have investigated the dilute solution properties of poly‐__p__‐bromostyrene, in a number of solvents, at temperatures ranging from 15 to 70°C. It was found that the unperturbed dimensions of this polymer are depending upon the nature of the solvent, as it was already observed for several polar polymers. The largest values of K~⊖~ were found in solvents tightly associated with the polymer chain, increasing thus the chain stiffnes. Poly‐__p__‐bromostyrene exhibits in benzene and in dioxane around 20°C a conformational transition which affects the unperturbed dimensions. This transition brings with it a rapid increase of the chain flexibility, as it could be shown from measurements of limiting viscosity number and of light‐scattering. Around 50°C in the same solvents, another transition was observed, which is affected by the solvent‐polymer (long range) interactions. Addition of a solvent (as DMF) able to give rise to specific interactions with the polar groups of the polymer chain inhibits all these transition phenomena. It is however difficult to claim that the two observed transition phenomena are really distinct. It may well be that in a rather broad temperature ran

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Author

Karayannidis, Petros ;Dondos, Anastasios

Publisher

Wiley (John Wiley & Sons); Wiley (ISSN 0025-116X)

Published

1971

Language

FR

Field

Chemistry (Physical Sciences)