RESUME:Nous avons etudie des copolymbes triskquenc6.s de I'isoprhe et de differents mkthacrylates d'alcoyles. Les comportements viscotlastiques de ces 'matkriaux sont ceux des elastomtres thermoplastiques du type SBS. La valeur du facteur de perte (tg6) de la phase caoutchoutique depend du pourcentage de la phase plastique et du procedt de mise en oeuvre du film. Nous avons Cgalement ttudie I'influence de la nature de la sequence ester (methyl, ethyl, propyl, butyl, isobutyl et diphhyl) et montrer son interaction sur la morphologie des materiaux et leurs modes de relaxations.
SUMMARY:Block copolymers with a central sequence of polyisoprene (12% of 1-4 structure) and poly(alky1-methacrylates) have been studied. The viscoelastic properties of these compounds are those of thermoplastic rubbers of the SBS type. The loss factor (tg6) of the rubbery phase changes with the ratio of plastic compound and with the processing of the films. We studied the influence of the ester sequences (methyl, ethyl, propyl, butyl, isobutyl and diphenyl methacrylates). We correlated the viscoelastic behaviour and relaxation processes of the materials with the nature of the sequence together with the morphology observed by electron microscopy.