Synthesis of homo- and copolymer containing sulfonic acid via atom transfer radical polymerization

Well-defined functional poly(p-phenyl styrenesulfonate) and poly(p-phenyl styrene-sulfonate-co-styrene) were successfully synthesized by the atom transfer radical polymerization (ATRP) using CuBr/bpy(PMDETA) catalyst and 1-phenylethyl bromide (1-PEBr) as an ATRP initiator in diphenyl ether (DPE) or dimethyl formamide (DMF). In both homo- and copolymers, the CuBr/PMDETA catalytic system in DPE or DME showed higher yield than CuBr/bpy and the polydispersity index (PDI) of polymer was low. Using PMDETA or bpy as a ligand in DMF, the high yield with high PDI was obtained than in DPE. We found that the CuBr/PMDETA catalyzed ATRP of p-phenyl styrenesulfonate and copolymerization with styrene comonomer in DPE proceeded in a controlled manner. The polymers containing sulfonic acid were obtained by the chemical deprotection of protecting group, followed by acidification. The molecular structure, molecular weights and thermal properties of the copolymers were determined by nuclear magnetic resonance (¹H NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively.