Poly(ethylene terephthalate) clay nanocomposites: Improved dispersion based on an aqueous ionomer

Poly(ethylene terephthalate) (PET) clay nanocomposites were synthesized using two different types of organo-modified clay: Cloisite 10A (a montmorillonite) and Somasif MEE (a synthetic fluoromica). In addition to these organo-modified clays, a nanocomposite using the unmodified clay, Somasif ME100, was also prepared. The facile method of preparation involved the dispersion of the clays in water together with an aqueous dispersion of an ionomer having a high level of compatibility with PET. After the removal of water, nanocomposite samples were prepared by a melt compounding route. Ionic interactions of the ionomer with the clay facilitated a high degree of exfoliation of the clay platelets in the PET matrix. Samples were characterized by TEM, XRD, melt rheology and TGA-MS. TEM analysis showed differences in the degree of clay platelet orientation and exfoliation between Cloisite 10A and the Somasif clays, with the Somasif MEE and ME100 clay additives giving a more ordered and exfoliated morphology. Melt rheology results were consistent with TEM observations with the more exfoliated samples giving higher viscosities. TGA-MS revealed that the Somasif ME100 sample showed a high level of thermal stability, while the organo-modified clay additives exhibited some thermal degradation at the PET processing temperatures.