Polyacrylate-clay nanocomposites were prepared by an in situ polymerization method followed by heterocoagulation. In the heterocoagulation method, a cationic polyacrylate emulsion was prepared by emulsion polymerization using a cationic initiator in the presence/absence of free surfactant, cetyl trimethylammonium bromide (CTABr), followed by mixing with an aqueous clay slurry. WAXD results and TEM images suggest that morphologies of these nanocomposites depend on preparation method, mixing method, and the amount of free surfactant. TG-DTG analyses demonstrate the improvement in thermal stability of these nanocomposites, while DSC results indicate no significant changes in glass transition temperature of these nanocomposites. (c) 2006 Wiley Periodicals, Inc.