Characterization of Poly (ethylene terephthalate)/SiO2 nanocomposites prepared by Sol–Gel method

Poly (ethylene terephthalate) (PET)/SiO2 nanocomposites were synthesized via the Sol–Gel method that involves two steps: terephthalic acid was first reacted with excess ethylene glycol to form bis (hydroxyethyl) terephthalate (BHET); then the tetraethoxysilane (TEOS) were transferred to the BHET followed by the Sol–Gel reactions at high temperature to form silica nanonetworks concurrent with polycondensation of BHET to produce the PET matrix. Transmission electron microscopy (TEM) showed that silica particle size was at nanoscale, and the nanoparticles were uniformly dispersed in the polymer matrix. Thermogravimetric analysis (TGA) results indicated that the activation energy of thermal degradation of the composites was largely improved. The flame retardancy of the composites was found to be improved according to cone calorimeter (CONE). The nonisothermal crystallization ability of the composites was found to be depressed according to differential scanning calorimetry (DSC).