Synthesis and characterization of anionic graft copolymers containing poly(ethylene oxide) grafts

Graft copolymers containing poly(ethylene oxide) side chain attached to maleic anhydride-alt-vinyl methyl ether (MA-VME) copolymer were prepared by coupling MA-VME and poly(ethylene glycol) monomethyl ether (MPEG) by esterification in DMF at 90degreesC. MPEG and dodecyl alcohol (DA) were grafted onto MA-VME copolymer in o-xylene at 140degreesC in the presence of p-toluene sulfonic acid as catalyst. The molecular weights of MPEG were found to influence the rate of the grafting reaction and the final degree of conversion. The graft copolymers were characterized by IR, GPC, and H-1-NMR. DSC was used to examine thermal properties of the graft copolymers. The analysis indicates that grafts have phase-separated morphology with the backbone and the MPEG grafts forming separate phases. The properties in aqueous solutions of these grafts were studied with respect to aggregation behavior and viscometric properties. In aqueous solution, the polymers exhibited polyelectrolyte behavior (i.e., a dramatic increase of the viscosity upon neutralization). Graft copolymers with DA have lower viscosities. (C) 2002 Wiley Periodicals, Inc.