Effect of swelling agent on the physical properties of PET–clay nanocomposite materials prepared from melt intercalation approach

A series of poly(ethylene terephathalate) (PET)/organo-modified clay nanocomposites were successfully prepared by melt intercalation through the twin-roller mixer. Two kinds of swelling agents are used as organo-modifiers of the pristine clay. Wide-angle X-ray diffraction (WAXRD) and transmission electron microscopy (TEM) were employed to study the morphology of the PET–clay nanocomposites. The quaternary alkylphosphonium salt (4-carboxybutyl) triphenylphosphonium bromide (Φ3P+-C4)-modified clay was found to show better dispersion capability than that of quaternary alkylammonium salt hexadecyltrimethyl ammonium bromide (Me3N+-C16)-modified clay that existed in the polymer matrix. The thermo-mechanical properties were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analyzer (DMA). The optical clarity was examined by UV–visible transmission spectra. The better dispersion of (Φ3P+-C4)-modified clay in PET leads to excellent improvement of physical properties such as optical clarity, thermal stability and mechanical strength of the PET–polymers than that of using (Me3N+-C16)-modified clay.