Effect of spherical and platelet-like nanoparticles on physical and mechanical properties of polyethylene terephthalate

Abstract

The influence of spherical (titanium dioxide (TiO2)) and platelet-like (Closite20A) nanofillers on the physical properties of polyethylene terephthalate (PET) nanocomposites was investigated. PET nanocomposites were prepared by melt blending of PET and nanofillers. Differential scanning calorimetry showed that PET nanocomposites had higher crystallinity than the neat PET, possibly due to the nucleating role of the nanoparticles. It was observed that the influence of nanoclays on crystallization of PET is more considerable than TiO2 nanoparticles. For PET/TiO2 and PET/clay nanocomposites, the highest value of crystallinity observed at 3 wt% and 1 wt% loading level of TiO2 and Closite20Ananoparticles, respectively. Scanning electron microscopic micrographs showed that uniform distribution and good dispersion of TiO2 through PET matrix were achieved at 1 and 3 wt% loadings but at higher loadings up to 5 wt%, nanoparticles tend to accumulate. Transmission electron microscopy and wide angle X-ray diffraction showed that the dominant structure of PET nanocomposites containing 1 wt% nanoclays was exfoliation while at higher loading levels, the shift in peak to lower angles and subsequent increase in platelet spacing suggest intercalated structure. The addition of TiO2 nanoparticles caused noticeable enhancement of PET ductility, while the incorporation of nanoclays into PET matrix developed a fragile structure with lower ductility.