C-60 as core of well defined hetero-star polymers.

Addition of "living" polymers such as polystyryllithium onto C-60 allows th e synthesis of well defined star-shaped macromolecules with a C-60 core bea ring six PS arms of about same length and an equal number of negative charg es located on the fullerene. If these latter an used to initiate the anioni c polymerization of methymethacrylate, a hetero-star consisting of a C-60 c ore with 6 polystyrene and 2 poly(methylmethacrylate) arms is obtained. A s econd way to prepare hetero-stars is to react the "living" stars with funct ional polymers bearing at one end a reactive halide. We were able to graft 2 additional PS chains of exactly the same or different length as the 6 bra nches of the starting 6-branch star, producing respectively a 8 branched st ar or asymmetric-star.