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.