A scalable approach for the mass production of chemically modified graphene has yet to be developed, which holds the key to the large‐scale production of stable graphene colloids for optical electronics, energy conversion, and storage materials, catalysis, sensors, composites, etc. Here, a facile approach to fabricating covalently modified graphene and its polymer nanocomposites is presented. The method involves: i) employing a common furnace, rather than a furnace installed with a quartz tube and operated in inert gas as required in previous studies, to treat a commercial graphite intercalation compound with thermal shocking and ultrasonication and fabricate graphene platelets (GnPs) with a thickness of 2.51 ± 0.39 nm that contain only 7 at% oxygen; ii) grafting these GnPs with a commercial, long‐chain surfactant, which is able to create molecular entanglement with polymer matrixes by taking advantage of the reactions between the epoxide groups of the platelets and the end amine groups of the surfactant, to produce chemically modified graphene platelets (m‐ GnPs); and iii) solution‐mixing m‐GnPs with a commonly used polymer to fabricate nanocomposites. These m‐GnPs are well dispersed in a polymer with highly improved mechanical properties and a low percolation threshold of electrical conductivity at 0.25 vol%. This novel approach could lead to the future scalable production of graphene and its nanocomposites.

The interface is well known for taking a critical role in the determination of the functional and mechanical properties of polymer composites. Previous interface research has focused on utilising reduced graphene oxide that is limited by a low structural integrity, which means a high fraction is needed to produce electrically conductive composites. By using 4,4 0 -diaminophenylsulfone, we in this study chemically modified high-structural integrity graphene platelets (GnPs) of 2-4 nm in thickness, covalently bondedGnPs with an epoxy matrix, and investigated the morphology and functional and mechanical performance of these composites. This covalently bonded interface prevented GnPs stacking in the matrix. In comparison with unmodified composites showing no reduction in electrical volume resistivity, the interface-modified composite at 0.489 vol% GnPs demonstrates an eight-order reduction in the resistivity, a 47.7% further improvement in modulus and 84.6% in fracture energy release rate.Comparison of GnPs with clay and multi-walled carbon nanotubes shows that our GnPs are more advantageous in terms of performance and cost. This study provides a novel method for developing interface-tuned polymer/graphene composites.

In spite of extensive studies conducted on carbon nanotubes and silicate layers for their polymer-based nanocomposites, the rise of graphene now provides a more promising candidate due to its exceptionally high mechanical performance and electrical and thermal conductivities. The present study developed a facile approach to fabricate epoxy-graphene nanocomposites by thermally expanding a commercial product followed by ultrasonication and solution-compounding with epoxy, and investigated their morphologies, mechanical properties, electrical conductivity and thermal mechanical behaviour. Graphene platelets (GnPs) of 3.57 AE 0.50 nm in thickness were created after the expanded product was dispersed in tetrahydrofuran using 60 min ultrasonication. Since epoxy resins cured by various hardeners are widely used in industries, we chose two common hardeners: polyoxypropylene (J230) and 4,4 0 -diaminodiphenylsulfone (DDS). DDS-cured nanocomposites showed a better dispersion and exfoliation of GnPs, a higher improvement (573%) in fracture energy release rate and a lower percolation threshold (0.612 vol%) for electrical conductivity, because DDS contains benzene groups which create p-p interactions with GnPs promoting a higher degree of dispersion and exfoliation of GnPs during curing. This research pointed out a potential trend where GnPs would replace carbon nanotubes and silicate layers for many applications of polymer nanocomposites.

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Rather than using graphene oxide, which is limited by a high defect concentration and cost due to oxidation and reduction, we adopted cost-effective, 3.56 nm thick graphene platelets (GnPs) of high structural integrity to melt compound with an elastomer-ethylene-propylene-diene monomer rubber (EPDM)-using an industrial facility. An elastomer is an amorphous, chemically crosslinked polymer generally having rather low modulus and fracture strength but high fracture strain in comparison with other materials; and upon removal of loading, it is able to return to its original geometry, immediately and completely. It was found that most GnPs dispersed uniformly in the elastomer matrix, although some did form clusters. A percolation threshold of electrical conductivity at 18 vol% GnPs was observed and the elastomer thermal conductivity increased by 417% at 45 vol% GnPs. The modulus and tensile strength increased by 710% and 404% at 26.7 vol% GnPs, respectively. The modulus improvement agrees well with the Guth and Halpin-Tsai models. The reinforcing effect of GnPs was compared with silicate layers and carbon nanotube. Our simple fabrication would prolong the service life of elastomeric products used in dynamic loading, thus reducing thermosetting waste in the environment.

In this communication we demonstrate that in the initial stages of deposition of ultrathin plasma polymer films, both the growth rate and the chemical composition of the films are affected by the nature of the substrate which is an important question surprisingly neglected until now.

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