In this paper, a novel graphene oxide (GO)/sodium alginate (SA)/polyacrylamide (PAM) ternary nanocomposite hydrogel with excellent mechanical performance has been fabricated through free-radical polymerization of acrylamide (AAm) and SA in the presence of GO in an aqueous system followed with ionically crosslinking of calcium ions. As-prepared GO/SA/PAM (weight ratio SA : AAm = 1 : 2) ternary nanocomposite hydrogel with 5 wt% of GO displays a compressive stress as high as 1.543 MPa at the compressive deformation of 70%. The tensile strength and modulus of the hydrogel achieved ∼201.7 and ∼30.8 kPa, respectively. In the meantime, the ternary nanocomposite hydrogels can recover a large proportion of elongation at breakage and exhibits good elasticity. Additionally, the GO/SA/PAM ternary nanocomposite hydrogel exhibited good adsorption properties for water-soluble dyes. After introducing GO, the dye adsorption capacities of the hydrogel were significantly improved.

Boron nitride nanosheets (BNNSs) are two dimensional crystals composed of boron and nitrogen atoms covalently bonded in a hexagonal manner with exceptional physiochemical properties. However, the researches on BNNS are rather limited due to the lack of an efficient method to prepare BNNS. In this study, we report a facile and efficient method for the fabrication of BNNS through liquid-phase exfoliation of hexagonal boron nitride particles (h-BNs) in methanesulfonic acid. The resultant BNNS can be readily disperse in a number of organic solvents, such as N-methyl-2-pyrrolidone. Transmission electron microscopy and atomic force microscopy confirms that the obtained BNNSs are mainly single or few-layered with a thickness less than 3 nm. X-Ray photoelectron and infrared spectroscopy reveal that almost no compositional change occurred in BNNS during the superacid-assistant exfoliation process. The BNNS holds great promise in a number of important applications as demonstrated in this study of poly [2,2′-(p-oxydiphenylene)-5,5′-bibenzimidazole] (OPBI)/BNNS composites. The OPBI/BNNS composites showed superior mechanical and thermal properties as compared to neat OPBI and h-BN reinforced ones.

Three-dimensional (3D) structures of graphene have attracted extensive interest for their practical applications, such as supercapacitors and catalyst supports. Self-assembly is a typical technique to fabricate macroscopic graphene materials integrated with various superior properties. However, an efficient and environmentally-friendly strategy is still needed. In this paper, we report a green and mild method for the synthesis of 3D architectures of graphene. This proposed method is based on the chemical reduction of graphene oxide (GO) with the aid of a range of natural phenolic acids and in situ self-assembly of graphene sheets via π–π interactions. The obtained monolithic graphene exhibits low density, super hydrophobicity, high porosity, excellent mechanical strength and electrical conductivity. These multifunctional products can be used as adsorbents for removal of oils, organic solvents and dyes from contaminated water, as well as electrode materials for supercapacitors.

Aramid macroscale fibers, also called Kevlar fibers, exhibit extremely high mechanical performance. Previous studies have demonstrated that bulk aramid macroscale fibers can be effectively split into aramid nanofibers (ANFs) by dissolution in dimethylsulfoxide (DMSO) in the presence of potassium hydroxide (KOH). In this paper, we first introduced the ANFs into the structure of graphene nanosheets through non-covalent functionalization through π–π stacking interactions. Aramid nanofiber-functionalized graphene sheets (ANFGS) were successfully obtained by adding the graphene oxide (GO)/DMSO dispersion into the ANFs/DMSO solution followed by reduction with hydrazine hydrate. The ANFGS, with ANFs absorbed on the surface of the graphene nanosheets, can be easily exfoliated and dispersed in N-methyl-2-pyrrolidone (NMP). Through a combination of these two ultra-strong materials, ANFs and graphene nanosheets (GS), the resultant ANFGS can act as novel nanofillers for polymer reinforcement. We used the ANFGS as an additive for reinforcing the mechanical properties of poly(methyl methacrylate) (PMMA). With a loading of 0.7 wt% of the ANFGS, the tensile strength and Young's modulus of the ANFGS/PMMA composite film approached 63.2 MPa and 3.42 GPa, which are increases of ∼84.5% and ∼70.6%, respectively. The thermal stabilities of ANFGS/PMMA composite films were improved by the addition of ANFGS. Additionally, the transparencies of the ANFGS/PMMA composite films have a degree of UV-shielding due to the ultraviolet light absorption of the ANFs in the ANFGS.