Synthesis and characterization of comb-like polyphenylenes via Suzuki coupling of polystyrene macromonomers prepared by atom transfer radical polymerization

1,4-Dibromo-2,5-bis(bromomethyl)benzene was used as initiator in atom transfer radical polymerization of styrene in conjunction with CuBr/2,2′-bipyridine as catalyst. The resulting macromonomer, with a central 2,5 dibromobenzene ring and the degree of polymerization of 16 at each side, was used in combination with 2,5-dihexylbenzene-1,4-diboronic acid, for a Suzuki coupling in the presence of Pd(PPh3)4 as catalyst. The obtained polyphenylene, with alternating polystyrene and hexyl side chains, has high solubility in common organic solvents at room temperature. The new polymer was characterized by GPC, 1H-NMR, 13C-NMR, IR and UV analysis. Thermal behavior of the precursor polystyrene macromonomer and the final polyphenylene was investigated by thermogravimetric analysis and differential scanning calorimeter/calorimetry analyses and compared.