Processable conductive graphene/polyethylene nanocomposites: Effects of graphene dispersion and polyethylene blending with oxidized polyethylene on rheology and microstructure

Abstract

Poor dispersion of graphene in non-polar polymer matrices creates composites with limited applications. A method to improve the dispersion of graphene in polyethylene (PE) via blending PE with oxidized PE (OPE) is examined. Graphene was produced by simultaneous thermal exfoliation and reduction of graphite oxide. Nanocomposites of graphene with PE as well as graphene with PE/OPE-blends were prepared by solvent blending. Improved dispersion of graphene in PE/OPE blends substantially decreases percolation from both rheological (0.3 vol%) and electrical (0.13 vol%) measurements compared to neat PE nanocomposites (1 and 0.29 vol%), respectively. A universal Brownian dispersion of graphene in polymers was concluded similar to that of nanotubes, following the Doi-Edwards theory. Micromechanical models, such as Mori-Tanaka and Halpin-Tsai models, modeled the mechanical properties of the nanocomposites. The nanocomposites microstructure, studied by small angle x-ray scattering, confirmed better dispersion of graphene at lower loadings and the formation of surface fractals in the blend/graphene nanocomposites; whereas only mass fractals were observed in neat PE/graphene nanocomposites.

Mass‐produced graphene—HDPE nanocomposites: Thermal, rheological, electrical, and mechanical properties

“…Polymer nanocomposites have shown enormous potential to significantly enhance the polymers properties by using nano‐scale fillers . Graphene has recently become one of the most promising nanofillers for polymer nanocomposites because of its extraordinary mechanical, thermal and electrical properties .…”

“…Graphene has recently become one of the most promising nanofillers for polymer nanocomposites because of its extraordinary mechanical, thermal and electrical properties . Graphene is a sp 2 ‐hybridized carbon layer with an atomic thickness, consisting of honeycomb‐like assembly of carbon atoms . This structure exhibits exceptionally high modulus (~1,000 GPa in tension), which can result in significant improvements in mechanical properties (over 100% increase in Young's modulus) when added to a polymer matrix .…”

Recent Developments Concerning the Dispersion Methods and Mechanisms of Graphene

“…Yang et al [73] found that the π-π structured plane of humic acid (HA) can be absorbed on the surface of graphene, which supplied oxygen-containing groups to graphene sheets to improve the dispersion of graphene in water. Iqbal et al [74] proposed an approach to …”

One-Step Synthesis of Hierarchical Micro-Mesoporous SiO2/Reduced Graphene Oxide Nanocomposites for Adsorption of Aqueous Cr(VI)

“…Graphene has been known as promising adsorbent with great potential in wastewater treatment [5][6][7] because of its large theoretical surface area (2630 m 2 /g) [8], remarkable electronic properties [9] and mechanical properties [10], and high ability of modification [11,12]. However, it is difficult to disperse graphene in water due to its hydrophobicity, agglomeration, and restacking [13][14][15], limiting its use in aqueous systems for decontamination.…”