Synthèse par voie radicalaire de polymères à extrémités hydroxylées, 9. Synthèse de polybutadiènes: étude des microstructures

Butadiene polymerization with hydrogen peroxide resulted in the simultaneous formation of oligomers, polymers, and high polymers. Analyses of their microstructures showed that oligomers have a higher content of 1,2‐structures (28%) than the polymers (22%). The nature of the chain ends was determined with low molecular weight compounds. The content of 1,2‐units is distinctly higher in the oligomers, which shows that initiation takes place preferably in 1,2‐ and propagation in 1,4‐position. Besides hydroxyl end groups, other functional groups were detected in small quantities in the low molecular weight products: aldehydes, ketones, acids, hydroperoxides, and epoxides. These functions result from secondary reactions such as transfer, initiation, or termination reactions with alcohol releasing radicals.