Investigation of the effect of graphene oxide on the properties of epoxy‐phthalonitrile nanocomposites

Abstract

A novel keto-ene containing phthalonitrile (PN) monomer was synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR) and 1 H and 13 C nuclear magnetic resonance spectroscopy. Graphene oxide (GO) was prepared from natural graphite using Hummer's method. The effect of the addition of GO with diglycidyl ether of bisphenol A (DGEBA) and phthalonitrile in the presence of diaminodiphenyl sulfone (DDS) as a curing agent has been investigated. The mechanical, thermal, and electrical properties of GO/epoxy-phthalonitrile (EP-PN) nanocomposites as a function of different weight percentage of GO (0, 1, 3, and 5 wt%) are reported. Dynamic mechanical analysis reveals that a maximum glass transition temperature (166.5°C) and storage modulus (3.3 GPa at 25°C) values are obtained for 3 wt% of GO content. FT-IR, X-ray diffraction, and Raman spectral techniques were employed to characterize the prepared GO and its extent of exfoliation in EP-PN nanocomposites. The dispersion of GO in the fractured surface of the composites was analyzed by scanning electron microscopy and transmission electron microscopy. GO/EP-PN nanocomposites show dramatic increase in dielectric properties compared to the neat EP-PN nanocomposites. All the prepared nanocomposites fabricated with GO show excellent thermal stability in nitrogen atmosphere.