Synthesis and characterization of a poly(acrylic acid)-graft-methoxy poly(ethylene oxide) comblike copolymer

A methoxy poly(ethylene oxide) (MPEO) grafted poly(acrylic acid) (PAA) comblike copolymer was synthesized by the direct condensation of MPEO onto the PAA backbone in the presence of dicyclohexyl dimethylcarbodiimide (DCC) and 4-dimethylaminopyridine (DMAP). Its chemical structure was characterized by Fourier transform infrared and ¹H-NMR spectroscopies. The effects of different catalysts, solvents, reaction temperatures, and reaction times on the grafting degree of the PAA-g-MPEO comblike copolymer were investigated. Compared to p-toluene sulfonic acid, DMAP/DCC as a catalyst markedly increased the grafting degree. The optimum reaction conditions were a tetrahydrofuran/water mixture solvent, a reaction temperature of 50°C, and a reaction time of 168 h.