Evolving Strategies for Producing Multiscale Graphene-Enhanced Fiber-Reinforced Polymer Composites for Smart Structural Applications

Abstract

Graphene has become an important research focus in many current fields of science including composite manufacturing. Developmental work in the field of graphene-enhanced composites has revealed several functional and structural characteristics that promise great benefits for their use in a broad range of applications. There has been much interest in the production of multiscale high-performance, lightweight, yet robust, multifunctional graphene-enhanced fiber-reinforced polymer (gFRP) composites. Although there are many reports that document performance enhancement in materials through the inclusion of graphene nanomaterials into a matrix, or its integration onto the reinforcing fiber component, only a few graphene-based products have actually made the transition to the marketplace. The primary focus of this work concerns the structural gFRPs and discussion on the corresponding manufacturing methodologies for the effective incorporation of graphene into these systems. Another important aspect of this work is to present recent results and highlight the excellent functional and structural properties of the resulting gFRP materials with a view to their future applications. Development of clear standards for the assessment of graphene material properties, improvement of existing materials and scalable manufacturing technologies, and specific regulations concerning human health and environmental safety are key factors to accelerate the successful commercialization of gFRPs.

Keywords: composites; graphene; polymers; smart materials.

Figure 1

a) The cumulative summary for the approximate number of graphene–polymer composites publications from 2004 to September 2019 (using Web of Science). b) The cumulative summary for patent application “graphene–polymer composites” as a function of application year. Note: patents remain unpublished for up to 18 months from their filing. Accordingly, 2018 and 2019 are under‐represented; Data updated as of June 2018.

Figure 2

a) Main supply chain factors affecting the rapid uptake of graphene. b) A comparison of the cost of graphene with the benchmark materials since 2010 to 2022. Reproduced with permission.^{[ 35 ]} Copyright 2020, John Wiley and Sons.

Figure 3

Market snapshot in 2014 and 2026 by IDTechEx. This will change as real applications sales grow. Source: www.IDTechEx.com/graphene.^{[ 43 ]}

Figure 4

Graphene applications roadmap. Adapted with permission.^{[ 38 ]} Copyright 2019, Graphene Flagship.

Figure 5

Some common production methods of graphene in relation to quality and scalability potential. Each method has been evaluated in terms of graphene quality (G), cost aspect (C; a low value corresponds to high cost of production), scalability (S), purity (P), and yield (Y) of the overall production process. Adapted with permission.^{[ 45 ]} Copyright 2020, Springer Nature.

Figure 6

a) Liquid phase exfoliation of graphite. 1) Starting material (graphite), 2) chemical wet dispersion, 3) ultrasonication, and 4) final dispersion after the ultracentrifugation process. Reproduced with Permission.^{[ 51 ]} Copyright 2019, OSA Publishing. b) Schematic showing the reduction process of GO. Adapted with Permission.^{[ 52 ]} Copyright 2019, IOP Publishing. c) the solution–gelation transition of graphene sheets upon switching pH values.

Figure 7

Schematics of the two proposed strategies for multiscale composite manufacturing.

Figure 8

Schematic of desired changes in degradation development with typical three degradation phases for FRP (unmodified) and nanoparticle modified FRP loaded in fatigue: fatigue life improvement by an extension of phase I and II (shift a) and a less pronounced degradation increase (shift b). Adapted with permission.^{[ 84 ]} Copyright 2019, Elsevier.

Figure 9

The general fabrication routes for graphene‐based polymer dispersions with GO or rGO. Reproduced with permission.^{[ 46 ]} Copyright 2019, John Wiley and Sons.

Figure 10

Radar charts comparing gPFRPs with benchmark CFRPs in relation to part performance and scalability potential. Each material system has been evaluated in terms of A) weight, B) specific strength, C) specific stiffness, D) impact strength, E) through‐plane electrical conductivity, F) anti‐corrosive properties, G) fatigue life/wear properties, H) raw material costs, I) manufacturing complexity, J) final part cost; a low value corresponds to manufacturing complexity, higher cost of raw materials, and manufacturing.

Figure 11

Schematic diagram of a) EPD, Reproduced with permission.^{[ 174 ]} Copyright 2019, Elsevier and b) dip‐coating process.^{[ 175 ]}

Figure 12

SEM micrograph of a) GnP‐coated CFs. Reproduced with permission.^{[ 88 ]} Copyright 2019, Elsevier. b) GnPs‐coated glass fabric. Reproduced with permission.^{[ 198 ]} Copyright 2020, Elsevier. c) Multilayered gFFRP composite, and d) Optical photograph of the cross‐section of gFFRP composite.

Figure 13

Radar charts comparing gPFRPs with benchmark MAs and OFCs in relation to part performance and scalability potential. Each material system has been evaluated in terms of A) weight, B) specific strength, C) specific longitudinal stiffness, D) electrical conductivity, E) response time, F) detection area, G) detection mode, H) sensitivity ratio, I) part assembly and manufacturing complexity, J) final part cost; a low value corresponds to manufacturing complexity and higher cost of raw materials and manufacturing.