Enhanced dispersion of nanoclays in poly(ethylene terephthalate)/clay nanocomposites using supercritical carbon dioxide

Abstract

Nanoclays were prepared using supercritical carbon dioxide (scCO 2 ) as a medium, and then blended with polyethylene terephthalate (PET) via conventional melt blending processing. The structure and morphology of nanoclays were investigated using wide-angle X-ray diffraction (WAXD) and scanning electron microscopy (SEM). It was found that, compared with the original organically modified layer silicates, smaller nanoclay tactoids and individual platelets morphology could be obtained after they were processed by scCO 2 , indicating scCO 2 processing could enhance exfoliation of nanoclays. WAXD and transmission electron microscopy measurements were used to evaluate the dispersion of nanoclays in the nanocomposites. The results indicated the conventional blending extrusion processing could help to improve the dispersion of nanoclays, and the nanocomposites containing scCO 2 pretreated nanoclays formed a looser clay stack and an improved intercalation structure, compared with those containing as-received nanoclays. Thermal and mechanical properties of the nanocomposites were also studied by differential scanning calorimetry (DSC) and dynamic mechanical analysis, and the results showed that crystallization rate, crystallinity, and storage modulus of the well-dispersed nanocomposites containing scCO 2 pretreated nanoclays were increased, compared with the neat PET and nanocomposites containing asreceived nanoclays or nanoclays prepared by conventional organomodification process in water. J. VINYL ADDIT. TECHNOL., 23:E58-E67, 2017.

Supercritical carbon dioxide (scCO2) dispersion of poly(ethylene terephthalate)/clay nanocomposites: Structural, mechanical, thermal, and barrier properties

“…Recently, several scCO 2 based processing techniques have been reported to effectively disperse clay and form polymer/clay nanocomposites with superior properties . Yang et al .…”