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Aminated polyethylene glycol (PEG-NH2) functionalized graphene nanosheets (PEG-rG) were successfully introduced into epoxy resin as a core-shell nanostructure to prepare the epoxy based dielectric composite. The overall mechanical and dielectric performances of the PEG-rG/epoxy nanocomposites were greatly improved in comparison with its counterparts employing with untreated graphene. The dielectric constant of PEG-rG/epoxy 1.5 wt% nanocomposites reached 84.3 at 100 Hz, two times higher than that of rG/epoxy 1.5 wt% system. What’s more, the dielectric loss is effectively reduced to a very low level (tan δ = 0.21).

Percolative poly(vinylidene fluoride) (PVDF) composites with high dielectric constant and low dielectric loss was successfully achieved by incorporating reduced graphene oxide (rGO) decorated with magnetic iron oxide (Fe3O4) (rGO@Fe3O4) nano-fillers. The morphology, structure, thermal, electrical and magnetic properties of the composites were investigated systematically by using SEM, XRD, FTIR, TGA, DSC, impedance analyzer and magnetometer, respectively. The presence of a tiny amount of poly(sodium 4-styrene sulfonate) (PSSNa) facilitated the homogeneous distribution of rGO@Fe3O4 nanoparticles and prevented the formation of an electrical conductive network within the PVDF matrix, resulting in an excellent dielectric performance of the rGO@Fe3O4/PVDF nano-composites. With 1.0 wt% rGO@Fe3O4 incorporated in PVDF, the nanocomposite exhibited a high dielectric constant of 1297 and a low dielectric loss of 0.26 at 100 Hz. Percolation model revealed that such improvements could be attributed to the synergistic effect of the inorganic Fe3O4 and rGO, whereby the electric charges were accumulated by forming many mini-capacitors in the bulk PVDF matrix. The structure-property behavior of the final nanocomposites was discussed.

MnFe2O4/cellulose nanocrystal (MnFe2O4/CNC) composites featured high catalytic activities on the decomposition of methylene blue (MB) were prepared by a novel approach, through which the H+ ions produced during the acid hydrolysis of cellulose are largely consumed. Attributed to their high specific surface areas, small particle size and low band gap, contributing to the generation of large number of reactive hydroxyl radicals from H2O2, the magnetic MnFe2O4 nanoparticles anchoring on CNC demonstrate pronounced improvements of catalytic activities on the decomposition of MB pollutants compared with that of the bare MnFe2O4. Specifically, the degradation degree of MB catalyzed by MnFe2O4/CNC composite containing 20 wt% of CNC is 99%, which suggests more than 60% increase than that in the bare MnFe2O4. More particularly, MnFe2O4/CNC composites featuring excellent magnetic properties exhibit an excellent recycling catalytic performance, suggesting a great promising candidate in application of environmental pollutant treatment.

Flexible natural rubber/magnetic iron oxide (Fe3O4)@reduced graphene oxide (NRMG) composites with segregated structure were prepared by a self-assembly method in latex. Various characterization techniques were employed to verify the successful preparation of Fe3O4@rGO and the formation of segregated structure within the bulk composites. Compared with natural rubber/reduced graphene oxide (NRG) composites, the presence of Fe3O4 enhances the electromagnetic interference shielding effectiveness (EMI SE) of NRMG composites. The EMI SE value of NRMG composite with 10 phr (part per hundred parts of rubber) rGO is 1.4 times higher than that of NRG composite with the same rGO content in the frequency range of 8.2–12.4 GHz. The specific EMI SE of NRMG composite reaches 26.4 dB mm−1, outperforming the ever-reported polymer/Fe3O4@rGO composites with low rGO content. Excitingly, the EMI SE of NRMG composite decreases only 3.5% even after 2000 bending-release cycles, demonstrating potential applications in flexible shielding materials.

Graphene aerogels featuring ordered and controllable architectures represent promising candidates for use in water purification. In this context, a unique method for directing the self-assembly of graphene oxide (GO) nanoplatelets in a sodium hydrogen sulfite (NaHSO 3 ) aqueous suspension is proposed, which leads to the formation of annular GO assemblies and ultimately turns into graphene millimeter-vortex ring (GMVR) aerogel after chemical reduction and freeze-drying process. In comparison to other spherical or cylindrical adsorbents, GMVR exhibits superior adsorption efficiency for the removal of contaminants, such as dyes and other organic solvents from wastewater. Particularly, the maximum adsorption capacity of GMVR for methylene blue was 1004 mg g −1 , which is much higher than that of conventional graphene-based materials. The remarkable absorbability of GMVR materials is closely related to their increased surface area as well as the shortened diffusion pathway. Such approach of preparing GMVR composites provides potential route for the future development of excellent adsorbents.

Electromagnetic interference (EMI) shielding foams featuring light weight and ultralow thermal conductivity have received attention in a diverse range of applications, but their limited service life makes them very challenging in realistic use. As such, prolonging their service life has aroused significant scientific and technical interest. Herein, we report a facile method to prepare a carbon nanotube/acrylic copolymer (CNT/AC) foam by using isobutane as a blowing agent. This strategy is effective in constructing a 3D porous architecture composed of a segregated CNT network impregnated with an AC polymer through a hot pressing foaming process. This unique structure endows the composite with superior EMI specific shielding effectiveness (for foams with 0.62 vol% CNTs: 1243.3 dB·cm2·g−1) and an extremely low percolation threshold and thermal conductivity (0.008 W·m−1·K−1). More intriguingly, the inherent long-chain entanglements give the foam a self-healing feature. Specifically, with the incorporation of 0.80 vol% CNTs, the healing effectiveness of the EMI shielding performance is greater than 79% in the frequency range from 8.2 GHz to 12.4 GHz. Overall, the resulting CNT/AC foam possesses numerous advantages such as light weight, thermal insulation and EMI shielding self-healing performance, suggesting great potential application value in aviation areas.

Graphene (GE)/natural rubber (NR) composites (RGE) with a conductive segregated network (RGES) are prepared by latex mixing. Results show that the RGES composite with GE content of 10 phr (RGES-10) exhibits excellent electrical conductivity of 2.7 S/m and good flexibility. After 4 tensile cycles and subsequent thermal treatment, the electrical conductivity of RGES-10 shifts to 4.4 S/m, nearly 2 times higher than that of unstretched RGES-10 samples. The increased conductivity indicates that the destroyed networks, which occur during the tensile process, can be healed during the post thermal treatment. In addition, RGES-10 composite possesses excellent heat propagation with a uniform temperature distribution. The steady-state temperature of the RGES-10 increases from 57 to 152 °C as the applied voltage increases from 10 to 20 V.

Elastomeric conductive composites (ECCs) based on carbonaceous fillers are very attractive and play a significant role in the field of smart sensors due to their excellent flexibility, high and wide-spectrum sensitivity as well as fast response to external stimuli. In this study, a lightweight and multi-sensing composite based on reduced graphene oxide/natural rubber (rGO/NR), is fabricated by a facile and cost-effective approach that combines the rGO assembling on rubber latex particles by graphene oxide in-situ reduction and mild drying of the resulting hydrogels. The resulting composites exhibit a reliable porous structure whereas the rGO is spatially distributed in a three-dimensional segregated morphology that percolates the samples. The composites are characterized by a low percolation threshold (

Polydispersed graphene was synthesized by grafting a thin layer of water-soluble amine functionalized polyethylene glycol monomethyl ether (PEG-NH2). PEG-NH2 functionalized graphene (PEG@rGO) was then introduced into epoxy resin via a facile solution mixing method. Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) verified that PEG was successfully grafted to the surface of graphene. The obtained PEG@rGO showed excellent dispersibility in solvents when compared to pristine graphene. As a “core-shell” filler, PEG@rGO filled epoxy nanocomposites displayed improved dielectric constant and reduced dielectric loss, exhibiting potential applications in energy storage capacitors. The mechanical strength and final decomposition temperature were also simultaneously increased.