Préparation et caractérisation de polymères-modèle à structure en étoile, par copolymérisation séquencée anionique

Abstract

Star-shaped polystyrene samples have been synthesized by anionic block-copolymerization of styrene and divinylbenzene (DVB), the proportion of the latter monomer being of the order of a few molecules per living end. Vacuum technique was used and benzene was chosen as solvent. The samples were found almost free of linear polystyrene, and of very low polydispersity. The number of branches was found to be a function of the overall concentration, of the amount of DVB, and of the molecular weight of the linear precursor. The results obtained with the meta and the para isomers did not differ significantly, as far as the products themselves are concerned. However, spectroscopic investigations carried out during reaction showed that the reactivity of the 2 double bonds of the para isomer differ significantly, whereas this is not the case with the meta isomer.