Rheological and physical properties of a nanocomposite of graphene oxide nanoribbons with polyvinyl alcohol
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In this work, the physicochemical and rheological properties of a nanocomposite of graphene oxide (GO) and thermoplastic polyvinyl alcohol (PVA) are reported. After adding deionized water to PVA, the sample was heated and mixed. The polymer solution was divided in two portions, each of them containing PVA in water. GO nanoribbons were added to one portion of the PVA solution in water to obtain the nanocomposite suspension (1% w/w). The similarity of the Fourier-transform infrared spectra of PVA and its related nanocomposite was assessed (both having similar peaks, an important observation as it indicated the water absorption on the samples). The scanning electron microscopy images showed that PVA lost its spherical shape in composites due to the GO sheets coating. The characteristic peaks O− (m/e 16) and OH− (m/e 17) were observed in the time-of-flight secondary ion mass spectrometry negative mode spectra of PVA and nanocomposite of GO nanoribbons with PVA. The analysis of the OH−, O−, C2H−, and C2 − peaks of PVA and the nanocomposite of GO nanoribbons revealed that a reduction occurred for GO nanoribbons when coated with PVA. The rheological behaviors of samples in solution were studied and their shear rate versus shear stress were assessed. A non-Newtonian rheological behavior of the nanocomposite of GO nanoribbons with PVA was observed. The dielectric response of the nanocomposite of GO-PVA featured a simultaneous increase of both real and imaginary part of the complex permittivity toward low frequency due to the contribution of charge carriers. These results provide more understanding about the physical, mechanical, and dielectric properties of GO-PVA nanocomposite to make it appropriate in the construction of embedded capacitors. The novelty of our work lies in the rheological and physical properties of this nanocomposite in comparison with those of PVA that have not been previously reported.
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