A method for making polyester nanocomposite materials by polymerization in the presence of exfoliated fibrous clay nanoparticles includes dispersing the nanoparticles in a mixture of diol, water, and sodium salt before polymerization, thereby improving the dispersion of the nanoparticles in the final nanocomposite. This results in enhanced mechanical properties, such as modulus, in articles made from the nanocomposite.