SYNTHESIS AND CHARACTERIZATION OF POLY(TETRAMETHYLDISILYLENE-CO-STYRENE)

Dechlorination of dimethyldichlorosilane using sodium in toluene at 110-degrees-C in the presence of styrene (for varying composition of the monomers) has resulted in copolymers which are soluble in common organic solvents. Characterization of these polymers by H-1, C-13, and Si-29 NMR spectroscopy, pyrolysis GC, and microstructural analysis reveals that they contain tetramethyldisilylene and styryl moieties as repeating units. Significantly, no monosilyl linkage was observed in these copolymers. In addition to the repeating units containing disilyl linkages, polysilyl linkages were observed at higher concentrations of DMDCS. Polystyrene blocks were observed when the styrene concentration was increased. GPC data reveal that the copolymers have a bimodal distribution and the low molecular weight fraction increases with an increase in the concentration of styrene. The present investigation strongly suggests that synthesis of polysilanes by dechlorination using sodium involves disilyl species as the probable reactive intermediates.