Characterization of Reduced and Surface-Modified Graphene Oxide in Poly(Ethylene-co-Butyl Acrylate) Composites for Electrical Applications

Abstract

Promising electrical field grading materials (FGMs) for high-voltage direct-current (HVDC) applications have been designed by dispersing reduced graphene oxide (rGO) grafted with relatively short chains of poly (n-butyl methacrylate) (PBMA) in a poly(ethylene-co-butyl acrylate) (EBA) matrix. All rGO-PBMA composites with a filler fraction above 3 vol.% exhibited a distinct non-linear resistivity with increasing electric field; and it was confirmed that the resistivity could be tailored by changing the PBMA graft length or the rGO filler fraction. A combined image analysis- and Monte-Carlo simulation strategy revealed that the addition of PBMA grafts improved the enthalpic solubility of rGO in EBA; resulting in improved particle dispersion and more controlled flake-to-flake distances. The addition of rGO and rGO-PBMAs increased the modulus of the materials up to 200% and the strain did not vary significantly as compared to that of the reference matrix for the rGO-PBMA-2 vol.% composites; indicating that the interphase between the rGO and EBA was subsequently improved. The new composites have comparable electrical properties as today’s commercial FGMs; but are lighter and less brittle due to a lower filler fraction of semi-conductive particles (3 vol.% instead of 30–40 vol.%).

Evaluation of Synergic Potential of rGO/SiO2 as Hybrid Filler for BisGMA/TEGDMA Dental Composites

“…Figure 4 shows the spectra of rGO and modified rGO (S-rGO). The spectra of rGO was typical and agreed with the literature [ 37 ], showing a broad peak at 3432 cm −1 due to the stretching vibrations of OH, NH and moisture and weak bands at 2919 and 2856 cm −1 for residual alkyl groups. The characteristic bands of carbonyl stretching and amine bending modes are assigned at 1714 and 1558 cm −1 , respectively.…”

“…Modification of rGO with the coupling agent γ-MPS was attempted using a method modified from literature [ 32 , 33 , 37 ]. In this case, γ-MPS (0.05 mL) was separately prehydrolyzed in 15 mL ethanolic aqueous solution (70 wt.%) for 2 h. The silane solution was added dropwise into a pre-suspended rGO (400 mg) in 250 mL of 70 wt.% ethanolic solution and refluxed at 60 °C for 2 h, then kept on stirring overnight at room temperature.…”

Antibacterial Activities of Aliphatic Polyester Nanocomposites with Silver Nanoparticles and/or Graphene Oxide Sheets

“…Nevertheless, RGO finds attractive applications in electronics, optoelectronics, composite materials and energy-storage devices [104]. It is also commonly used as a filler material for polymers to form functional polymer nanocomposites and bionanocomposites [47,105,106,107,108,109]. The disadvantage of this chemical reduction strategy is the use of highly toxic hydrazine and sodium borohydride.…”

Readily Dispersible Chemically Functionalized Reduced Graphene Oxide Nanosheets for Solution-Processable Electrodes and Conductive Coatings

“…7,8 More recently, poly(n-butyl methacrylate) chains were polymerized from rGO and reduced the weight and brittleness of similar composites used for field grading materials. 9 In a previous investigation, our group demonstrated the utility of the Williamson ether conditions to graft alkyl chains onto GO and then reduce by using hydrazine. 26 The resulting nanoparticles exhibited enhanced dispersion and miscibility with thermoplastics; however, their electrical conductivity was significantly lower than rGO.…”