The Effect of Particle Size Distribution On the Dispersion of Nanoclays in PET/Clay Nanocomposites

The effect of clay particle size distributions on their dispersion in Poly(ethylene terephthalate)/clay nanocomposites has been studied. A two-step centrifugation method has been used to remove large particles from commercial montmorillonite (MMT) to prepare centrifuged nanoclay (CMMT). Scanning electron microscopy (SEM) of aqueous dispersions of MMT and CMMT illustrated that average particle size of CMMT in water is much lower than that of MMT in water. PET/clay nanocomposites with MMT and CMMT have been prepared by using a modified melt-blending method of mixing PET with a clay slurry instead of direct introduction of dried clay to PET. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) results show better dispersion of CMMT particles into the polymer matrix. Melt viscosity results revealed that good dispersion of CMMT into PET matrix decreases the effect of hydrolysis degradation of PET in the presence of water. Differential scanning calorimetry (DSC) results indicated that the nucleating effect of clay particles and crystallinity of samples are influenced by the particle size distribution of nanoclays and the morphology of final nanocomposites.