Preparation and characterization of PET blended with silica–polystyrene hybrid nanocomposites

Silica–polystyrene (Si–PS) nanocomposite latex particles were prepared by emulsion polymerization using Hwangtoh clay as the silica source and blending with polyethylene terephthalate (PET) by melt extrusion. The Hwangtoh clay was mechanically grounded as nanoscale. XRD measurements showed more crystallized Hwangtoh clay in nano-dimension than that of raw material with crystallite sizes (t) of 108.52 and 126.7 nm, respectively. SEM (scanning electron microscope) measurements showed that the dispersed Si–PS hybrid nanocomposite had a D _h of ~350 nm within the PET matrix. FTIR (Fourier transform infrared spectroscopy) measurements exhibited the characteristic absorption peaks of Si–O–Si stretching vibrations and Al–O–Si bending vibrations from both the Si–PS hybrid structure and PET/Si–PS composite. X-ray diffraction (XRD) measurements exhibited a characteristic Si diffraction peak of 2θ value at 25° and 29°, both from Si–PS hybrid nanoparticles and PET/Si–PS composites. The blending of PET with a Si–PS nanocomposite was determined by XPS (X-ray photoelectron spectroscopy) analysis, which showed three distinctive peaks representing the interatomic bonding of carbon. In XPS measurements, the decomposition of the Si 2p core peak demonstrated that the Si atom from Hwangtoh clay is composed of four chemical states such as Si⁰, Si⁺ (Si₂O), Si²⁺ (SiO), and Si³⁺ (Si₂O₃). Our results provide evidence of the successful encapsulation of silicate from Hwangtoh clay in a PS shell, and further blending with PET by the melting extrusion method.