Thermal degradation investigation of poly(ethylene terephthalate)/fibrous silicate nanocomposites

Based on the fibrous silicates (palygorskite, PT) organically modified by water-soluble polyvinylpyrrolidone (PVP), poly(ethylene terephthalate) (PET) nanocomposite with good dispersion of the PT nano-particles was prepared via in situ polycondensation. The thermal degradation behavior of PET and PET/PT nanocomposite was investigated by thermogravimetric analysis (TGA) under non-isothermal conditions at various heating rates in air and nitrogen, respectively. The apparent activation energies of the samples were evaluated by Kissinger and Flynn-Wall-Ozawa method. It is suggested that, during thermal decomposition in nitrogen, the clay as a mass-transport protective barrier can slow down degradation of polymer, but the catalytic effect of metal derivatives in clays may accelerate the decomposition behavior of PET. The combination of these two effects determines the final thermal stability of nanocomposite. However, in air atmosphere, the oxidative thermal stability of PET/PT nanocomposite was obviously superior to that of pure PET.