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

Abstract

Hydrolysis of poly(ethylene terephthalate) (PET) during processing in the presence of Fe 2 O 3 (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 SiO 2 nanoparticles increased the glass transition temperature (T g ) of PET, incorporation of IO nanoparticles led to a decrease in T g . There was an increase in rheological storage modulus (G ) of PET with incorporation of SiO 2 nanoparticles 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 zeroshear rate viscosity (η 0 ) increased with incorporation of SiO 2 nanoparticles. 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 (M v ) measurements showed that the molecular weight decrease found via rheological studies was in good accordance with theM v values.

The Synergy of Nanosilica and Zinc Diethyl Hypophosphite Influences the Flame Retardancy and Foaming Performance of Poly(Ethylene Terephthalate)

“…The complex viscosity jη * j decreased with the addition of nano-SiO 2 . According to research by Ebadi-Dehaghan [31] and Yao [32], nano-SiO 2 improved the modulus and viscosity of PET/SiO 2 nanocomposites by microcrosslinking PET molecular chains. In this paper, the reduction of complex viscosity and storage modulus would be related to the chain extension reaction of PET.…”