Synthesis, characterization and rheological properties of three different associative polymers obtained by micellar polymerization

We report the synthesis, characterization and rheological properties in aqueous solutions of three different water-soluble associative polymers (AP's) (telechelic, multisticker and combined). Polymer chains consisting of water-soluble polyacrylamides, hydrophobically modified with low amounts of N,N-dihexylacrylamide and a linear hydrophobic initiator. These have been prepared via free radical micellar polymerization. We compare the properties of these different polymers, with respect to the localization of the hydrophobic groups, using steady-flow experiments. In the semidiluted regime we clearly differentiate two different zero-shear viscosity (eta(0)) -vs- concentration (C) behaviors; a first semidiluted regime unentangled, where the viscosity increases strongly and directly with c and a second regime entangled, where the viscosity increases proportionally to C-4, independently of the localization of the hydrophobic group.