CARBANIONS ON GRAFTED C-60 AS INITIATORS FOR ANIONIC-POLYMERIZATION

Two methods to introduce negative charges on a C-60 and the further us e of these carbanions as initiators for anionic polymerization of styr ene and methyl methacrylate were investigated. From the potassium salt s of C-60, obtained by reduction with potassium naphthalenide, only th e hexaanion is able to polymerize MMA, and that by electron transfer s o that no fullerene is attached to the PMMA. In a second method, polys tyryllithium was added to C-60 to form ''living'' star molecules with a C-60 core bearing a well-controlled number of branches (i.e., carban ions). Six carbanions have to be located on the C-60 to initiate anion ic polymerization of styrene by addition onto the monomer, while five are enough to initiate the more reactive MMA. Stars with seven PS bran ches and heterostars with six PS and two PMMA have been produced.