Nanocomposites based on acrylic (butyl acrylate-co-methyl methacrylate-co-acrylamide) terpolymer and various commercial montmorillonites were synthesized by an "in situ" batch emulsion polymerization method. A complex emulsifier system containing sodium dodecyl sulphate (SDS) and a polymeric stabilizer was used in the polymerization. The minimum emulsifier concentration necessary to obtain stable latex depended on nanoparticle type and was established by several trials. Based on the experimental data two groups of stable latexes were obtained and characterized. The first nanocomposite latex group (Group A) was obtained by using lower emulsifier content and included Cloisite 93A, Cloisite 30B, Nanomer 1.31 PS, Cloisite Na(+) clays while the second group (Group B) had higher emulsifier content including Cloisite 15A, Cloisite 20A, Dellite 67G and Nanomer 1.44P clays. The nanocomposite emulsions were characterized by means of particle size and zeta potential analyzes. The intercalation/exfoliation of the nanoparticles in acrylic latex was assessed by XRD and SEM. The structural characterizations of the nanocomposite films were performed by FTIR, mechanical properties were tested by DMTA and thermal behavior was analyzed by DSC and TGA.