Preparation and characterization of poly(ethylene terephthalate)/clay nanocomposites by melt blending using thermally stable surfactants

Poly(ethylene terephthalate) (PET)/clay nanocomposites were prepared by melt blending and their morphologies and properties were investigated through X-ray diffraction, bright field transmission electron microscopy, thermogravimetric analysis and cone calorimetry. Three clays were comparatively studied - montmorillonite, hectorite and magadiite - all organically modified with thermally stable surfactants developed in this laboratory. Two such organic modifications were investigated, alkyl-quinolinium surfactants and vinylbenzyl-ammonium containing copolymers; both organic modifications combine high enough degradation temperature to allow for melt processing with PET, and also favorable thermodynamics for nanocomposite formation with PET. All nanocomposites showed about the same value for the peak heat release rate (PHRR). The amount of char increases after nanocomposite formation and this could account for the PHRRs.