Covalently bonded interfaces for polymer/graphene composites

Abstract

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.

A facile way to produce epoxy nanocomposites having excellent thermal conductivity with low contents of reduced graphene oxide

“…Furthermore, GO has been reported to promote the homopolymerization of epoxy resin [13]. These factors may change the molecular weight between crosslinks of the epoxy during crosslinking, as has been reported previously [10,11,34,35]. Indeed, nanoclays are known to produce a similar effect when used as fillers in epoxy polymers, e.g.…”

Improving the fracture toughness properties of epoxy using graphene nanoplatelets at low filler content

“…This was accompanied with a 55% increase in modulus. 47 In contrast, similar fracture toughness improvements were seen by using 4,4′-methylene diphenyl diisocyanate, with no significant improvement in modulus. 48 In this paper, a series of low loading (<1 wt%) plasma functionalized-GNP-epoxy nanocomposites were prepared and various properties were investigated to assess the mechanical and thermal properties of the nanocomposites.…”

“…Covalent functionalization of GNPs has been shown to give significant enhancement over non-functionalized platelets in epoxy-nanocomposites. [47][48][49] The fracture toughness has been improved by up to 40% over non-functionalized GNPs by covalent functionalization with 4,4′-diaminophenylsulfone. This was accompanied with a 55% increase in modulus.…”

In situ thermally reduced graphene oxide/epoxy composites: thermal and mechanical properties

“…As discussed elsewhere (Yang et al 2009), the increase in the storage modulus may be attributed to good interfacial adhesion between the rGO and the epoxy matrix due to the chemical interaction between the functional groups on the GO and epoxy during the in situ reduction. This chemical interaction between the GO and epoxy may also lead to an increase in the molecular weight between cross-links of the cured epoxy matrix (Zaman et al 2011;Ma et al 2013;Yousefi et al 2013) as the rGO content is increased. The number average molecular weight between cross-links, M nc , are listed in Table 1.…”