Synthesis of Quaternary Ammonium Ion-Grafted Polyolefins via Activation of Inert C-H Bonds and Nitroxide Mediated Radical Polymerization

A TEMPO-functionalized isotactic poly(1-butene) macroinitiator was synthesized via rhodium-catalyzed activation of the alkane C-H bonds in polyolefin side chain using a boron reagent and subsequent transformations of the boronate ester group in the polymer. These functionalization processes did not induce cross-linking or degradation of the polymer chains. Nitroxide mediated radical polymerization of dipropyl(4-vinylphenyl)amine with the macroinitiator produced high-molecular weight amine-grafted copolymers of the polyolefin. Adjusting the ratio of polar monomer concentration to macroinitiator concentration controlled the concentrations of amine blocks in the graft copolymers up to 10 mol %. Quaternization of the amine-grafted copolymers with methyl triflate generated ammonium ion blocks along the side chain of the graft copolymers. A systematic decrease of contact angle in a series of ammonium ion-grafted copolymers was observed through water contact angle measurements, suggesting that the graft polymerization and the quaternization led to increased hydrophilicity in the polymers. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4519-4531, 2009