Síntese de nanomateriais de grafeno para utilização em nanocompósitos poliméricos

Abstract

Because of its unprecedented physical and chemical properties, graphene has attracted the attention of researchers searching to produce composite materials with unique properties. In this way, it has been studied the incorporation of graphene oxide loads into polymers and analyzed their influence on the mechanical, electrical and thermal behavior of the resulting composites. In this work, we present the preparation and the influence of the incorporation of graphene oxide (GO) on polyvinyl alcohol (PVOH). The mechanical reinforcement, by the incorporation of 0.5 wt%, 0.1 wt% and 1 wt% of graphene oxide into the polymer matrix, was estimated. The strategy involved the production of graphite oxide from graphite, using the modified Hummers method. The method was carried out by the addition of sulfuric acid (H2SO4), potassium permanganate (KMnO4) and hydrogen peroxide (H2O2), followed by the exfoliation of graphite oxide into sheets of graphene oxide by the use of ultrasound, and finally the preparation of the GO / PVOH nanocomposites by a simple solution mixing method. The synthesized materials were characterized by X-ray diffraction, Raman spectroscopy, and gravimetry. The analysis of the GO / PVOH films were carried out via tensile and UV-vis tests. Gravimetry showed that the solution of graphite oxide synthesized had a homogeneous concentration. X-ray diffraction (XRD) showed that the oxidative process of graphite precursor into graphite oxide was efficient. The stress-strain analysis confirmed the increase in mechanical strength of the polymeric film with the incorporation of graphene oxide load, while for the strain it was not possible to obtain conclusive data. The optical analysis showed a whitening of the film during the tensile test, indicating an alignment of the polymer chains and crystallization of the films. The UV-vis spectra showed that the pure PVOH film exhibited a high transparency, however, for the films with 0.1wt%, 0.5wt% and 1.0wt% GO this transparency decreased considerably.