Characterization and rheological properties of model alkali-soluble rheology modifiers synthesized by reversible addition–fragmentation chain-transfer polymerization

Model alkali-soluble rheology modifiers of different molar masses were synthesized by the reversible addition–fragmentation chain-transfer polymerization of methyl methacrylate, methacrylic acid, and two different associative macromonomers. The polymerization kinetics showed good living character including well-controlled molar mass, molar mass linearly increasing with conversion, and the ability to chain-extend by forming an AB block copolymer. The steady-shear and dynamic properties of a core-shell emulsion, thickened with the different model alkali-soluble rheology modifiers, were measured at constant pH and temperature. The steady-shear data for latex solutions with conventional rheology modifiers exhibited the expected thickening, whereas the associative rheology modifiers showed contrasting rheology behavior. The dynamic measurements revealed that the latex solutions thickened with the conventional rheology modifiers exhibit solid-like (dominant G') behavior as compared with the associative rheology modifiers that give the latex solution a liquid-like (dominant G") character. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 223–235, 2003