The Ability of Rheological Studies for Assessment of Hydrolysis During Processing of Polyethylene Terephthalate Nanocomposites.

Hydrolysis of poly(ethylene terephthalate) (PET) during processing in the presence of Fe2O3(ferrite) nanoparticles (IO) was investigated. Three nanocomposites, filled with 2.5, 5, and 10 wt.% of IO nanoparticles, were processed in the melt state at 260°C. A nanocomposite containing 5 wt% of nano-silica was also prepared similarly as the blank sample. Dynamic mechanical thermal properties of the nanocomposites showed that, while the introduction of SiO2nanoparticles increased the glass transition temperature (Tg) of PET, incorporation of IO nanoparticles led to a decrease in Tg. There was an increase in rheological storage modulus (G′) of PET with incorporation of SiO2nanoparticles in the low-frequency region. Conversely, the incorporation of IO nanoparticles led to a decrease in G′ in this frequency region. The decrease of G′ was attributed to hydrolysis of PET due to the presence of impurities in the IO. The zero-shear rate viscosity (η0) increased with incorporation of SiO2nanoparticles. Conversely, this value decreased with incorporation of IO nanoparticles. While rheological studies showed a significant decrease in molecular weight of the PET due to hydrolysis, the IR spectroscopy did not have sufficient ability for assessment of the hydrolysis phenomenon. However, the viscosity-average molecular weight () measurements showed that the molecular weight decrease found via rheological studies was in good accordance with thevalues. [ABSTRACT FROM PUBLISHER]