Polybutadiènes hydroxytéléchéliques, 2 Microstructure et fonctionnalité des polyméres obtenus par voie anionique. Etude par résonance magnétique nucléaire du proton et du carbon 13

Abstract

Abstract The examination, by 1 H NMR, of anionic hydroxytelechelic polybutadienes in conjunction with accurately measured M n values allows the simultaneous determination of the number average functionality and the identification of the nature of the chain ends bearing the functional groups. The microstructure of the polymer chains has been studied by 13 C NMR. A high proportion of isolated vinyl units has been found only if the percentage of vinyl is less than 70%, whereas the vinyl sequences are atactic. During the functionalization, if lithium is utilized as catalyst, only one molecule of ethylene oxide is added at each end of the polymer chain. With potassium, ethylene oxide polymerizes. Owing to the chain ends, reaction mechanisms of the addition of ethylene oxide onto the living polymer have been proposed.