SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF A NOVEL AND STARLIKE C-60(PMS)(X)(CH3)(X) COPOLYMER

A novel starlike C-60(PMS)(x)(CH3)(x) (x=1-3) copolymer was prepared b y reaction of a living poly(alpha-methylstyrene) (PMS) carbanion with C-60, followed by a capping reaction with methyl iodine. The character ization techniques used are UV-vis, FT-IR, GPC, DSC, TGA, ESR, C-13 NM R, SEM, XRD, cyclic voltammetry (CV) and fluorescence spectroscopy. Th is starlike polymer has a visibly earthy yellow cast when compared wit h the unfunctionalized parent polymer (PMS), and is highly soluble in some common organic solvents. Poly(alpha-methylstyrene) is essentially transparent at wavelengths longer than 280 nm, and its main absorptio n band is at 250 (vs) nm. Covalent attachment of the multiple PMS arms to the C-60 core results in the bathochromic shift of the above band and the appearance of a new absorption band at 328 nm (pi-->pi). This new band is one of the characteristic absorptions for organofullerene s. The thermal stability and oxidation/reduction activation of pure PM S are enhanced apparently by C-60 chemical modifiction. It is also fou nd that in this copolymer there are mainly two kinds of paramagnetic s pecies, whereas no ESR signal in pure poly(a-methylstyrene) is detecte d, and this indicates the non-existence of unpaired electron or free r adical. (C) 1997 Elsevier Science Ltd.