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Abstract

In this paper, graphene, graphene/matrix, and graphene/fiber nanocomposites, including their synthesis process, fabrication, properties, and potential applications, were reviewed. It was found that several synthesis techniques for nanographene were developed, such as liquid-phase exfoliation and chemical vapor deposition. In addition, some fabrication processes of graphene/matrix and graphene/fiber-based nanocomposites were made, including in-situ polymerization, nanostitching in that single layer nano graphene plate could be interconnected by means of carbon nanotube stitching, resin transfer molding, and vacuum-assisted resin transfer molding. Several properties, including mechanical, thermal, and electrical, on the graphene nanoplatelets materials were summarized in this review paper. It was realized that graphene, graphene/matrix, and graphene/fiber nanocomposites have extraordinary mechanical, thermal, and electrical properties used in advanced engineering applications, including soft robotics, microelectronics, energy storage, biomedical and biosensors as well as textile industry.

Keywords

Graphene graphene nanoplatelets nanocomposites electrical properties thermal conductivity mechanical properties

Introduction

Numerous researches have been carried out to develop novel materials or tune existing materials with an inimitable combination of properties that can be replenished with the traditional metallic compounds, ceramics, and polymeric substances. Graphene nanoplatelets composite has certain potential used in high performance requiring areas such as space/aerospace, marine, defense, robotic, medical and transportation due to its high specific strength/stiffness ratio, chemical resistance, and better corrosion properties [1,2]. This requirement led to the advancement and expansion of nanocomposite materials. Due to their novel properties and diversified application usage, nanocomposites garnered increasing noticeable consideration as an indispensable part of our everyday life [3 –5].

Graphene nanoplatelets (GNPs) composites have a high surface area to volume ratio, lightweight, easy to fabricate, and flexible [6 –8]. The small amount of GNPs in neat composite improved its properties due to the enhancement of the interfacial region [9,10]. It has revealed that the inclusion of nanoparticles not only noticeably improved the interfacial bond but also increased the mechanical, thermal, and electric properties of composites [11 –13]. To enhance the material performances, the interest of using nanomaterials as reinforcements such as carbon nanotubes (CNTs) [14 –16] and graphene nanoplatelets (GNPs) [17 –19] have been widely explored as fillers for their integration into polymer composites. As a result, their demanding properties were exploited to develop functional materials [20]. Graphene is a two-dimensional (2 D) atomic crystal material [21] and an array of one-atom-thick planar sheets comprised of sp2-bonded carbon atoms closely organized in a crystal honeycomb lattice. This makes them light and strong, including flexible and rigid material as illustrated in Figure 1. Charge carriers of graphene reveal excessive intrinsic mobility and can move for thousands of inter-atomic distances without scattering [22]. It shows higher thermal conductivity [23], impermeability, stiffness, and improved mechanical and optical properties [24 –26]. Therefore, graphene and graphene-based nanocomposites show a range of prospective applications due to their remarkable properties, from high-performance electronic devices [27], to composite materials [28], and wearable electronics [29].

Figure 1.

All graphitic forms of graphene as 2D flat nanosheet, top and 3D multilayered graphite formation, bottom [21].

This review was prepared in four sections. The first section dealt with various synthesis methods on graphene. The second section was on the fabrication method of graphene nanocomposites. The third section was related to the properties of graphene, and its nanocomposites, and the last one was related to the application of GNPs composites. Therefore, this review study provided comprehensive and diverse information on graphene nanoplatelets composites.

Synthesis of graphene

Graphene has a densely packed, huge surface area due to van der Waals interaction forces, and therefore, graphene layers tend to restack and reaggregate. Several attempts have been devoted to creating techniques for synthesis to achieve high-quality pristine graphene because of its planar hexagonal array and high aspect ratio. Mass-level production synthesis of graphene prevention of aggregation is a critical parameter. Finding a suitable and well-fitted fabrication method for mass-level graphene production and having defect-free graphene is the main objective. Generally, graphene synthesis approaches can be categorized into two categories as top-down and bottom-up methods. On the other hand, each method can be used depending on the end-use requirements. The methods are classified as presented in Figure 2, and the graphene synthesis methods are schematically shown in Figure 3. Mechanical exfoliation [31], chemical synthesis [32,33], chemical exfoliation [34,35] epitaxial growth [36 –38], and chemical vapor deposition [39] have been extensively studied. Other methods including arc-discharge method [40], electrochemical exfoliation [41,42], microwave synthesis [43,44], gas-phase synthesis [45,46], total organic synthesis [47,48], solvothermal synthesis [49,50], unzipping of carbon nanotubes (CNT) [51,52] and flash graphene synthesis [53] have been well explained.

Figure 2.

Classification of graphene synthesis techniques.

Figure 3.

A schematic demonstration of various graphene synthesis methods. (a) Micromechanical cleavage, (b) anodic bonding, (c) photo exfoliation, (d) liquid-phase exfoliation, (e) growth on SiC, (f) precipitation from metal, (g) chemical vapor deposition, (h) molecular beam epitaxial and (i) chemical synthesis; Reprinted with permission from [30].

Mechanical exfoliation

Graphite consists of stacked layers of multiple graphene sheets, which are bound together by weak van der Waals forces. Graphene can be made from a pure graphite sheet by breaking these forces [54]. This method is a well-known simple technique for graphene production [31]. An adhesive tape is required, between which graphite flakes are placed and the outer side is peeled off constantly. This process is repeated. As the tape is peeled off and replaced with a new tape, the flakes break up into thinner flakes, and this repetitive process continuous until efficient single layers are accomplished. Through this process, exfoliation of graphite into few-layer and single-layer graphene sheets with lateral sizes can be possible. Geim et al. [21] makes a freestanding graphene sheet using thick, highly oriented pyrolytic graphite (HOPG) and a repetitive peeling-off process from the graphite. Then, the tape was dispersed in acetone solution, and an oxidized Si-wafer was dipped into the solution to move the flakes onto the substrate. The deposited flakes were extensively studied, especially for the electrical properties [55]. Mechanical exfoliation is a versatile and simple process to get defect-free graphene for fabrication, but the main obstacle is large-scale production. On the other hand, micromechanical exfoliation has been applied to fabricate graphene utilizing the mechanical process by generating shear forces. From the mechanical point of view, the main task is to mechanically overcome the Van der Waals’s attraction between the graphene layers within the bulk precursor. Chen et al. [56] made single and few-layer graphene sheets exfoliated from natural graphite via mechanical exfoliation using a three-roll mill machine with a polymer adhesive. Despite its shortcomings, micromechanical exfoliation persists as the preferred method for basic research.

Liquid-phase exfoliation

Liquid-phase exfoliation (LPE) has emerged as the most popular method for mass production. It is a simple and accessible process in which pristine graphite is exposed to a solvent to degrade the van der Waals forces between interconnected layers [57]. A schematic representation of the liquid-phase exfoliation process is shown in Figure 4. This process can be applied to exfoliate graphite in various liquid media by external driving forces such as ultrasonication, electric field, or shear forces to achieve spontaneous exfoliation into graphene sheets. Graphite is dissolved into an appropriate solvent followed by exfoliation. N-methyl pyrrolidine (NMP) and N, N-dimethylformamide (DMF) [59] are used as solvents. Liquid-phase exfoliation of graphite by ultrasonic techniques is of particular importance, as this simple process can produce neat graphene films ready for organic functionalization. This also allows the integration of additives, for example, surfactants [57], antioxidants [60], and polymers [61,62].

Figure 4.

Liquid-phase exfoliation process of graphite, schematic; Reprinted with permission from [58].

The liquid-phase exfoliation process usually involves three operations: (1) graphite must be dispersed in a solvent, (2) exfoliation, and (3) purification [58]. The expansion and collapse of voids in liquids due to pressure fluctuations induce exfoliation through ultrasonication, cavitation, and shear forces. After that, the graphene-solvent interaction is required to stabilize the inter-sheet attractive forces [63]. Some of the solvents are not cost effective, corrosive, high boiling points, and are typically toxic. Ultrasonication-assisted LPE has been widely applied to prepare the dispersions of graphene; perhaps there is a problem of high energy-extensive consumption and lower efficiency. High-shear mixing and micro fluidization bring new strength to the development of liquid-phase exfoliation. Removing surfactants as dispersants is quite troublesome. As a result, prepared graphene may show poor performance in this method.

Chemical vapor deposition (CVD)

Chemical vapor deposition (CVD) is an efficient and well-known process to produce graphene. This process can achieve good quality, uniformity with many domains, controlled graphene layer numbers, and a large scale of the produced graphene with small defects [64]. CVD requires the activation of gaseous reactants and the resulting chemical reaction, with the generation of an invariant solid deposit over an appropriate substrate, for example, Ni [65], Cu [66], Fe [67], Pt [68], or their alloys [69], ethanol [70], methane [71], hexane [72] and botanic camphor [73]. CVD is a recognized and adaptable technique for graphene synthesis [74]. The CVD growth of graphene comprises two types of chemical reactions in its deposition process: homogeneous gas-phase reactions and heterogeneous chemical reactions [75]. The gaseous precursor undergoes pyrolysis to form carbon species, and it is placed on the outside of the substrate where nucleation develops, and the carbon structure of graphene grows. Typically, to lessen the reaction temperature and to enhance the pyrolysis of the precursor, a catalyst is utilized. Generally, the CVD graphene process involves eight steps, as illustrated in Figure 5 [74].

Figure 5.

Steps involving chemical vapor depositions (CVD) graphene process.

A precursor in the CVD process requires that carbon-containing gasses (e.g., methane, CH₄) or liquid vapors from carbon sources (e.g., alcohols) need to be decomposed on transition metals wherever carbon is soluble. Some carbon is thought to precipitate as a graphite film at improved temperatures (900 –1100°C) in metal when it is cooled. At high temperatures, pyrolyzed carbon atoms can form a graphitic structure from dissociated carbon atoms. Metal catalysts stimulate graphitic structure formation expansion as well as lower energy barriers for precursors pyrolysis. Among the various metal catalysts, such as Ni and Cu is desirable due to their etching ability and cost efficiency [66]. It has been reported that uniform graphene films were synthesized over a large area [65] via methane on Cu foils, were constructed for mass production of the graphene films [39]. Figure 6 shows thermal-CVD and plasma-enhanced CVD methods [75] schematically.

Figure 6.

(a) Thermal-CVD and (b) Plasma- enhanced CVD processes where reactants transfer (1), thermal or plasma activation (2), from the main gas stream layer the boundary reactants transport through gas diffusion (3), adsorption of reactants (4), bulk diffusion of species (5), surface migration to the growth of the film (6), desorption of by-products (7), transport of by-products (diffusion) and return to the main gas stream (8), and by-products transportation from the deposition area (9) By-products transportation from the deposition area; Reprinted with permission from [75].

The chemical vapor deposition process (CVD) can be divided into two forms, thermal chemical vapor deposition [76,77] and plasma-enhanced chemical vapor deposition [78]. Thermal CVD is often used, and heating is the main driving criterion for the reaction. Ahmed et al. [79] reported single layer to few layers’ graphene on polycrystalline Ni by thermal CVD treating by solid precursor, camphor at ambient pressure. However, using plasma can facilitate pyrolysis temperature reduction. In the case of pressurized operation, there are two groupings, atmospheric-pressure CVD, and low-pressure CVD [80]. Substrate selection is crucially essential, and diversified substrates can be used. Metals, especially Cu, thrive the most as it acts as a catalyst and, the low carbon adsorption tendency of Cu allows easy control for the formation of large-area homogeneous mono or bilayer graphene. At low temperatures, the plasma produces reactive radicals of gaseous carbon precursors by pre-cracking, resulting in high-quality monolayer graphene films [81].

Epitaxial growth

When a single crystalline layer is deposited on a single crystalline substrate, an epitaxial layer is formed, which is recognized as epitaxial growth [82]. Through this process, fabrications of high-crystalline graphene onto single-crystalline SiC substrates are made. Depending on the substrate, two common epitaxial growth techniques have been developed, namely, homo-epitaxial and hetero-epitaxial growth [83]. When the deposited film materials are the same substrate, it is defined as homo-epitaxial growth, and if the substrate is different from the deposited substrates specified as hetero-epitaxial growth. Initial transport dimensions have been reported to grow on multilayer epitaxial graphene grown-up followed by thermal decomposition of SiC in ultrahigh vacuum [84,85]. Epitaxial growth of graphene on SiC is usually for wafer-based applications, for example, electronic devices or parts, and as such, it is not necessary to wipe the graphene from the original substrate [86]. Gupta and co-workers also explained the transport method of SiC in graphene on the C-surface of 3 C-SiC (111) at T > 1200°C [87].

Fabrication of graphene nanocomposites

The graphene nanocomposite processes play significant functions in defining the graphene into polymers. Many attempts have been taken to disperse uniform and homogenous graphene into the polymer matrix. Graphene integrated composites have been fabricated mainly by the following methods as solution mixing, melt blending, in-situ polymerization, and electrospinning. A short description of these fabrication processes are given below.

Solution mixing technique

Homogenous dispersion of graphene in the polymer matrix is a critical issue during the manufacturing of graphene nanocomposites to get strong bonding between nanographene sheet and matrix [88,89]. Solution mixing is a commonly practiced technique to manufacture graphene reinforced polymer composites since it is pliable to tiny sample sizes/low viscosity for filler dispersion. Generally, this technique requires three steps. First, graphene needs to disperse in an appropriate solvent by sonication or magnetic stirring. Then, the nanofiller suspension is integrated into the polymer in the same solvent or in a sorted solvent by means of stirring or shear mixing. Lastly, the obtained nanocomposite film is washed with water to remove the remaining solvent and dried. A number of graphene nanocomposites have been prepared by this process as graphene/epoxy [90], graphene/polystyrene [91], graphene/poly (methyl methacrylate) [92], graphene/ethylene-vinyl acetate copolymer [93], graphene/polyvinylidene fluoride [94], graphene/poly(ε-caprolactone) [95] and graphene/polypropylene [96]. Moreover, it is essential to find an approach to inhibit aggregation sheets by increasing the solubility properties of graphene in the relevant solvents. Due to the use of large amounts of organic solvents in the production, this process is not sustainable for the environment, especially for industrial production.

In-situ polymerization

In-situ polymerization is one of the effective synthesized manufacturing methods to make uniform dispersion of graphene in the nanocomposite [97]. Nanocomposite’s preparation requires mixing a monomer liquid with filler. Then, the monomer’s polymerization will develop the expected manufactured product. After that, the product is normally precipitated out and separated or cast as thin films. The graphene precursors and monomer are dispersed in a respective solvent and ultra-sonicated for even dispersion of the solution. Soon afterward, an initiator is inserted to produce the polymer. By the nature of the preferred product, this process can vary to form a pervasive range of categories and synthesis routes. The main benefits of this process are that the filler does not need to exfoliate before the formulation of the nanocomposite. Because of the strong interaction between the filler and the polymer, homogeneous dispersion has occurred rapidly and provides the first-rate miscibility for high-level filler loading in the polymer [98]. Some examples of graphene-based polymer nanocomposites include graphene/polystyrene [99], graphene/polyaniline [100], and graphene/epoxy [101,102] and graphene/polyacrylonitrile nanocomposites [103]. Figure 7 represents a typical example of an in-situ polymerization process.

Figure 7.

A schematic illustration of PA6T-graphene nanocomposite by in-situ polymerization. (PA: polyamide); Reprinted with permission from [104].

Melt blending

Melt blending is another technique used for the preparation of graphene nanocomposites film. This is relatively a more cost-effective, environment-friendly, and large-scalable technique. Melt blending is a process accomplished in the presence of inert gas (argon, nitrogen, or neon) but solvent is not essential. In this method, a solid filler (graphene) is used, and a thermoplastic polymer is blended via shear mixer and melted. Melt blending relies profoundly on the disentanglement of the polymer structure during their molten phase. The main disadvantages are the poor dispersity of the graphene in the thermoplastic matrix and damage of graphene sheet under high shear forces during processing [105]. Melt blending is well-suited with extrusion and injection molding. This method is toxin-free however facile dust formation is the major shortcoming in particular greater graphene ratio [106]. Li and co-workers [107] developed PA6/GO-g-hindered phenol antioxidant nanocomposites via melt processing (Figure 8). PA6 molecules onto graphene oxide surface were obtained through the formation of H-bonding, and graphene oxide was exfoliated and equivalently spread in the matrix. Some of the product examples of melt blending include polypropylene/graphene composites [108], polyethylene terephthalate/graphene nanocomposites [109] and polycarbonate/graphene nanocomposites [110].

Figure 8.

An illustration of formulation of PA6/GO-HP nanocomposites (PA: Polyamide; GO: Graphene oxide); Reprinted with permission from [107].

Electrospinning

Electrospinning is a process to form nanofibers or nanowebs with directly from solution under the electrical field as shown in Figure 9. This process is relatively simple, flexible and cost-effective. It can be potentially implemented in various fields such as tissue engineering, chemical and biological sensing, energy generation, and textiles [112 –114]. There are some clear reasons to incorporate graphene and its derivatives into electrospun nanofibers. The critical task is to enrich the electrospun material’s mechanical and electronic properties [115]. The precursor preparation blending includes dissipating the polymer and graphene in a solvent such as dimethylformamide (DMF) [112].

Figure 9.

A schematic explanation of fabrication of GO-doped Polyvinylidene fluoride (PVDF)/CuO/Al nanocomposites by using electrospinning; Reprinted with permission from [111].

The electrospinning process is established on the theory of ‘‘electrostatic attraction” of charges. During this process, the surface tension of the polymer solution inside the syringe can be externally charged by using a high voltage supply at the tip of the needle. To collect the ejected fibers oppositely charged collector is put at some distance (∼10 cm). During the high voltage (∼10–30 kV) transport [116], the solution in the syringe emerges out to overcome the surface tension and the hemispherical surface at the needle tip eventually elongates form a cone-like formation called the ‘‘Taylor cone”. The repulsive force overcomes the surface tension of the solution when a critical voltage value is reached, and a charged jet of the solution is ejected from the tip of the cone. The application of the high voltage precedes to ultra-fine composite fibers formation occurred with diameters in the nanometer range [117], which are electrospun as the solvent evaporates when the jet moves in the air, dropping the polymer fibers on the collector. Consequently, the electrospun fibers possess a high surface-to-volume ratio, lower density, and better mechanical strength. Polymer types and viscosity, solvent, voltage, the needle used to collector distance, and polymer flow rate is the critical process parameters. The drawback of the process includes small pore size and shortage of proper cellular infiltration inside the fibers. In the design and cellular migration, several attempts are made by introducing, heprasil, and mixing with polymers with different mortification behavior [113]. Some of the material examples by electrospinning are polyaniline/poly (methyl methacrylate)/amino-functionalized graphene [118], nylon/graphene nanocomposites [119], polycaprolactone/graphene nanocomposites [120], graphene oxide doped polyvinylidene fluoride/CuO/Al nanocomposites [111], polyamide/graphene oxide nanocomposites [121] and polystyrene/reduced graphene oxide nanocomposites [122].

Fabrication process of fiber-based graphene nanocomposites

The fiber-reinforced nanocomposites (FRC) fabrication process implies the preparation process of the fiber preforms and reinforcing these preforms along with the polymer matrix material [123]. Traditional 2 D fabric is generally used as fiber reinforcement. However, it suffered Mode-I delamination due to a lack of the through-the-thickness fibers. Therefore, several methods have been introduced to improve the out-of-plane directional properties through three-dimensional (3 D) weaving, 3 D braiding, and stitching processes [124]. Currently, carbon nanotubes and graphene nanoplatelets have been used in preform as a form of two-dimensional dry or prepreg fabric or dry 3 D preforms. Recently, nanostitching method was developed to use nanomaterials (MWCNTs or GNPs) during the preform formation and composite process [125,126]. On the other hand, composite processes can be categorized as open molding and closed molding processes [127 –129]. The open molding process is defined as when resins and fiber reinforcements are exposed to air during hardening. The closed molding process is when raw materials are cured within a two-sided mold or inside a vacuum bag (close off from the atmosphere). Selection of composite manufacturing technique is mainly based on the component of materials, tooling flexibility and their properties considering end-use requirements [130].

Resin transfer molding and vacuum-assisted resin transfer molding

Figure 10(a) and (b) represents the composite fabrication process of Resin transfer molding (RTM) and Vacuum-assisted resin transfer molding (VaRTM), respectively. The RTM process represents a closed-cavity molding method that provides dimensional stability and smooth surface of the composite [133]. In these processes, a dry fiber reinforcement preform is in the mold cavity, which closes the mold and is held in a clamping media. A liquid thermosetting resin is injected into the closed mold at a pressure (1 to 10 bar) [134]. As the liquid matrix flows through the dry fibers, it wets them and shifts air from the mold. The curing reaction is achieved at room or elevated temperature. The VaRTM process unites fiber arrangement, resin injection, and cure in one phase. A dry fabric preform is pulled out by resin by applying vacuum pressure. Then, the inlet line is further closed, drawing a vacuum onto the system. When the inlet line is open, a pressure gradient is formed, driving the matrix to impregnate the fibers [135].

Figure 10.

(a) RTM; Reprinted with permission from [131] and (b) VaRTM techniques, schematic [132].

Nanostitching

Figure 11 exhibits nanostitching method for making multi-nanostitched nanocomposites. In this technique, multiwall carbon nanotubes (MWCNTs) in the epoxy matrix were dispersed by employing a magnetic mixer and an ultrasonic mixer (200 watts, 40 KHz). After that, the MWCNTs/epoxy was vacuumed in a chamber. The carbon or aramid nanoprepreg fabrics and nanostitching yarns were made by using the carbon nanotubes or graphene nanoplatelets mixtures via hand lay-up technique. They were pre-cured by employing an air oven. The carbon or aramid nanoprepregs were layered and stitched in their out-of-plane direction. The nanostitched prepregs were then located in a metal mold wrapped with Teflon film and were cured in a hot press. Finally, they were removed from the mold as a form of multi-nanositched composites [125,126,136,137]. We are currently using the graphene nanoplatelets in the nanostitching technique at Nano/Microfiber Preform Design and Composite Laboratory in the Department of Textile Engineering in Erciyes University, supported by Scientific Research Unit (EUBAP) under contract number FDK-2020-10069. The result will be disseminated to share with readers.

Figure 11.

Nanostitching method for making multi-nanostitched nanocomposites; Reprinted with permission from [125,126].

Properties of graphene

Physical

Graphene has appeared as one of the most encouraging nanomaterials due to its distinctive arrangement of outstanding properties. These properties have yielded an exciting material with enormous potentiality for application in various high-performance devices and end-uses. Graphene nanoplatelets (GNPs) are a combination of a single layer, few layers, and nanostructured graphite that are commercially obtainable, and its thickness can differ from 3 to 100 nm. Its lateral size is 25 µm, and it is noted that while the number of layers is 10, graphite is generally considered a 2 D-like material. Table 1 presents the physical properties of graphene [138].

Table 1.

Some of the physical properties of graphene materials.

Physical properties of nanographene
Charge carrier mobility	∼2,50,000 (cm² V⁻¹ S⁻¹)
Thermal conductivity	∼5200 (Wm⁻¹K⁻¹)
Transparency	∼97.7%
Specific surface area	∼2630 (m²/g)
Young’s modulus	∼1TPa
Tensile strength	∼1100 GPa
Band gap	Zero

Mechanical

Graphene has a two-dimensional planar sheet structure and a hexagonal crystal lattice followed by covalent bonds between carbon atoms. Naturally, graphene is found in two forms: “monolayer” and “free-standing” [22]. Graphene owns some substantial mechanical properties like in-plane stiffness, high Young’s modulus, tensile strength, flexural strength because of the hexagonal 2-D crystal lattice consisting of sp2 hybridized C-C bonds. Monolayer graphene with defect-free is regarded to be a strong material yet [139]. However, it is worth mentioning that thermal and electronic transmission in graphene is very responsive to interruptions of the sp²-bonding network, but mechanical properties are substantially more tolerating of defects [140]. Table 2 shows some of the mechanical properties of graphene materials [143].

Table 2.

Mechanical properties of graphene material.

Method	Material	Mechanical Properties	References
AFM	Mono layer	E = 1 ± 0.1 TPaσ _int = 130 ± 10 GPa at ε_int = 0	Lee et al. [139]
Raman	Graphene	Strain ∼1.3% in tensionStrain ∼0.7% in compression	Tsoukleri et al. [141]
AFM	Mono layer grapheneBilayer grapheneTri-layer graphene	E = 1.02 TPa; σ = 130 GPaE = 1.04 TPa; σ = 126 GPaE = 0.98 TPa; σ = 101 GPa	Lee et al. [142]

Thermal

The heat flow direction of graphene can be divided into in-plane and out-of-plane directions. In-plane heat flow is more prominent than out-of-plane, and it is formed because of covalent sp2 bonding among carbon molecules, while out of plane is emitted from feeble van der Waals coupling [144]. Graphene-based transistors are recipients of in-plane heat flow reliant on a specific network. The heat flow can be regulated by phonon scattering, interfaces, and edges. Eventually, the rare thermal properties of graphene come from its 2 D structure, creating a powerful area for new breakthroughs of heat-flow physics, and potentially taking the lead for thermal appliances. The expanded graphite was observed to be the most efficient, having an in-plane thermal conductivity of 6.7 Wm⁻¹ K⁻¹ in the ribbon sample containing 40 wt% graphite [145].

Graphene is used as fillers to increase thermal conductivity. The thermal conductivity of single-layer graphene at room temperature is in the range ∼3000–5300 Wm⁻¹K⁻¹ of the Raman G peak frequency [146]. Yu et al. demonstrated that few graphene layers were useful filler for epoxy composites. It improved the thermal conductivity by more than 3000% (at ∼25 vol % loading) integrating into epoxy and exhibited a thermal conductivity κ = 6.44 W/m K [147]. So, graphene sheets can perform like hurdles to inhibit heat generation propagation from the outer atmosphere in a polymer matrix and enhance thermal constancy. Balandin et al. [148] determined the thermal conductivity of single-layer graphene (SLG) by utilizing confocal micro-Raman spectroscopy. A schematic representation of the experimental setup and the subsequent Raman spectrum of SLG is illustrated in Figure 12.

Figure 12.

(a) Illustrated the excitation laser light focused on a graphene layer suspended across a trench. (b) Raman spectrum with G peak region logged at two excitation power levels. (c) a shift in G peak spectral position shift versus power transfer; Reprinted with permission from [148].

Thermal conductivity is expressed as following equation (1) for plane heat wave case:

K = (\frac{1}{2} π h) (\frac{Δ P}{Δ T})

(1)

Where, h is the thickness of single-layer graphene. The intrinsic temperature $Δ T$ rise because of variation in heating power $Δ P$ . The final expression of thermal conductivity for the radical heat wave is provided as following (equation (2))

K = χ^{G} (\frac{L}{2 h W}) (\frac{δ ω}{δ P})

(2)

Where δω is the small alter in peak position because of a shift in δP and is computed from the curve slope in Figure 12(c). Graphene temperature coefficient χ^G is −1.6 × 10⁻²cm⁻¹/K. So, the thermal conductivity of single-layer graphene is from ∼4.8 × 10³ to ∼5.3 × 10³ W/mK on in average. Few layers of graphene (2 to 4 layers) by Raman Opto-thermal are found ∼2800 − 1300 W/mK [149].

Electrical

The distinctive atomic arrangement of the carbon atoms in graphene permits its electrons to easily move at exceedingly high velocity without the notable chance of scattering, conserving valuable energy typically lost in other conductors. Graphene can conduct electricity at the limit of zero mass carrier’s intensity since the electrons do not appear to slow down or localize [150]. The electrons of graphene behaved like a relativistic Dirac fermion system [151], a linear energy spectrum, and revealed some exceptional electronic properties such as the quantum Hall effect [152], absence of the Anderson localization [153]. Colloidal graphene quantum dots with chemically derived have been developed [154]. There are some critical properties as superior charge carrier mobility, ambipolar electric field effect [155], ballistic transport [156], chirality [157], weak scattering of charge carriers [158], and weak anti-localization [159]. Graphene has very high charge mobility because of the electronic arrangement ranging between 2000–15000 cm² V⁻¹S⁻¹ [160]. The most remarkable phenomena observed in graphene are quantum Hall effects and substantial control of quantum interference effects. It was noted that the electrical properties of graphene can be linearly improved incorporating of free charge carriers such as dopants [161] and the charge carrier density.

Optical

The optoelectronic properties of graphene are entirely recognized and combined with the polymer matrix [162]. Graphene can be tuned with the ultra-wideband [163], zero bandgap and strong contact of Dirac Fermions with electromagnetic radiation [164]. Graphene can absorb 2.3% of the incident light at one atomic thickness [165]. The rare optical properties of graphene are produced by a conical band of the electrons and holes at the Dirac point. It shows also high optical transmittance, low optical reflectance, luminescence, photoluminescence [166], quenching properties, and fluorescence quenching capabilities [167] due to its distinct electronic structures [168]. Additionally, the opto-electrical characteristics of the graphene film are very responsive to its layer numbers [169] and do vary with the layer number. The more graphene layers produced the greater light absorption at the expense of the lower optical transparency. It was found that single-layer graphene has an optical transmittance of 97.4%, and this decreases linearly with the number of layers. The luminescence and photoluminescence properties of graphene are successfully being applied in various biological functions [170]. Moreover, the transparency of graphene increases from monolayer to few-layer graphene, which decreases its surface area [171].

Properties of graphene nanocomposites

Graphene improves the performance of polymer-based composites due to its high strength and high modulus properties [172]. Recently, it has become a novel class of nanofillers for resinous composites. There are some factors on which the properties of polymer/graphene composites depend on such as the filler’s dispersion, bonding amongst filler and matrix, filler to matrix ratio and the graphene sizes. It was reported that filler dispersion, size of filler, and the interfacial bonding between reinforcements and matrix are crucial aspects for the overall properties of the resultant composites [173]. Bhanuprakash et al. described that graphene oxide could improve the interfacial properties effectively between carbon fiber and epoxy and enhance the interlaminar shear strength by 47% of composites [174]. Structural features, morphology, weight fraction, rate of dispersion, modification of the surface, and interfacial bonding between graphene and polymer are the main parameters which influence the composite properties.

Mechanical properties

The studies on the mechanical properties of polymer/graphene nanocomposites revealed that resin modulus was improved with the addition of the graphene. Such as, the modulus of epoxy resin was improved about 31% by addition of the graphene platelet (0.1 wt%) [175]. Additionally, several researchers reported that the mechanical properties of nanocomposites were significantly improved with the addition of graphene nanoplatelets [176 –179]. Numerous factors that manipulate the mechanical properties of graphene-associated materials as $γ$ -ray irradiation was noticed to substantially impact on structure-properties relationship [180,181]. It was concluded that the addition of nanographene (0.2%) in the carbon/epoxy composite increases its mechanical properties due to the locking of graphene in the structure [182]. A low amount of GNPs in the polymer matrix (1-2 wt%) considerably increased the fatigue performance of nanocomposite [183].

Tensile

A number of experimental studies indicated that the evidence integration of graphene into the composites improves the tensile properties of the composites [184 –186]. A short record of graphene epoxy nanocomposites studied in tensile properties values is presented in Table 3. Tang et al. [90] scrutinized the effect of graphene dispersion while Wang et al. [173] analyzed graphene nanoplatelet size impact on tensile, flexural modulus and strength of a graphene/epoxy nanocomposite. Yao et al. observed that when 0.8 wt % graphene was added to epoxy nanocomposites, the tensile strength and elongation at break increased by (37%) and (63%), respectively, as compared with neat epoxy [199]. Lee et al. [200] reported that functionalized graphene (0.1 wt%) improved the mechanical properties of epoxy composite compared to the pristine. Another study showed that epoxy with 1.5 vol.% GO enhanced the tensile strength, modulus and hardness of composite [25]. Tang et al. [187] studied surface functionalization of graphene oxide (GO) which was accomplished by refluxing GO with a diamine and polyetheramine. It was found that 2.7 vol% of functionalized GO/epoxy nanocomposites showed higher tensile modulus (536%) and strength (269%) compared to the pristine graphene/epoxy nanocomposites. It was identified that the mechanical properties of carbon fiber/epoxy/GO (0.2 wt.%) composites exhibited enhancement in the tensile strength, modulus, toughness, flexural strength by almost 34%, 20%, 83%, and 55%, compared to the neat composite, respectively [182]. The tensile strength and modulus of graphene oxide (1 wt.%) added epoxy composites were 29.2% and 22.0% higher than those of neat epoxy at a cryogenic temperature [184]. The inclusion of 0.25 wt% graphene nanoplatelets (GNPs) to epoxy nanocomposites showed the best improvement in tensile strength (20%) compared to the neat composite [176].

Table 3.

Tensile properties of graphene/epoxy nanocomposites.

Type of sample	Preparation method	Filler loading(wt%)	Tensile modulusincrease(%) GPa	Tensile strength increase(%) MPa	References
GNPs/epoxy	Shear mixing	6 wt%	23.5%	–54% decrease	King et al. [9]
GO/epoxy	Three-roll mill	1 wt%	12% at 0.1 wt%	13% at 0.5 wt%	Bortz et al. [18]
f-GNPs/epoxy	Three-roll mill	1 wt%	15.8%	38% at 0.5 wt%	Moghadam et al. [88]
GNPs/epoxy	Solution mixing	5 wt%	48.8 %	–36% decrease	Wang et al. [173]
Silanized silica NPs/GO/epoxy	Mechanical mixing	1 wt%	22.0%	29.2%	Jiang et al. [184]
Silane-f-GO/epoxy	Ball milling process	0.25 wt%	10%	48%	Wan et al. [185]
f-GO/epoxy	Mechanical mixing	2.7 vol%,	536%	269%	Tang et al. [187]
G-P/epoxy	Mechanical mixing	5 wt%	25%	21% at 2.5 wt%	Yasmin and Daniel [188]
GNPs/epoxy	Solution mixing	1 wt%	11.5%	11%	Zakaria et al. [189]
GNPs/epoxy	Solution mixing	5 wt%	28%	3% at 1 wt%	Prolongo et al. [190]
f-GNPs/epoxy	Solution mixing	1 vol%	8.6%	−14.5% at 0.25 vol%	Meng et al. [191]
f-Gr/epoxy	Solution mixing	0.1 wt%	57%	57%	Wan et al. [192]
f-Gr/epoxy	Solution mixing	1.5 wt%	12%	97% at 0.4 wt%	Liu et al.[193]
f-GNR/epoxy	Ball milling	0.15 wt%	14%	--	Nadiv et al. [194]
GNPs/epoxy	Three-roll mill	1 wt%	13%	−14%	Imran and Shivakumar [195]
RGO/GO/epoxy	Mechanical mixing	0.4 wt%	20%	52%	Ramos-Galicia et al. [196]
f-GO/carbon fiber/epoxy	Resin transfer molding	0.5 wt%	20%	15%	Chen et al. [197]
TRGO/epoxy	Three-roll mill	1 wt%	105%	108%	Hsu et al. [198]

GNPs: graphene nanoplatelets; GO: graphene oxide; f-GNPs: functionalized graphene nanoplatelets; G-P: Graphite platelet; f-Gr: functionalized graphene; f-GNR: functionalized graphene nanoribbon; f-GO: functionalized graphene oxide; RGO: reduced graphene oxide; TRGO: thermally reduced graphene oxide.

Flexural

Graphene nanoplatelets are found to be inexpensive and successfully applied as nanofillers to improve the flexural performance of the composites [201,202]. The larger surface area of GNPs increases the contact area with the matrix. It maximizes the stress transfer between the matrix and GNPs [203]. A summary of flexural properties of graphene/epoxy nanocomposites is presented in Table 4. GNPs addition (0.5%) in the resin increased the flexural modulus and toughness by 14% and 28% compared to the control, respectively [209]. Another study observed that GNPs coated carbon fiber/epoxy composite (0.25 wt%) improved the fatigue life of the neat composite [176]. Naebe et al. manufactured covalent functionalized epoxy/graphene nanocomposites and demonstrated 22% and 18% improvement in flexural strength and modulus, respectively, as illustrated in Figure 13 [204].

Table 4.

Flexural properties of graphene/epoxy nanocomposites.

Sample type	Preparation method	Optimum loading Wt%	Flexural modulus (GPa)%	Flexural strength (MPa)%	References
GO/epoxy	Three-roll mill	1 wt%	12%	23%	Bortz et al.[18]
GNPs/epoxy	Solution mixing	5 wt%	25.7 %	11.5%	Wang et al. [173]
GO/CF/epoxy	VaRTM	0.25 mg/ml	28.2%	25%	Bhanuprakash et al. [174]
GNPs/CF/epoxy	Hand Lay up	3 wt.%	22%	82% (90° direction)	Qin et al. [178]
GNPs/epoxy	Solution mixing	1 wt%	28%	17 %	Zakaria et al. [189]
f-GNR/epoxy	Ball milling	0.15 wt%	–	7%	Nadiv et al. [194]
GNPs/epoxy	Three-roll mill	1 wt%	3%	–7%	Imran and Shivakumar et al. [195]
GO/CF/epoxy	RTM	0.5 wt%	16%	15%	Chen et al. [197]
f-GNPs/epoxy	Ultrasonication	0.1 wt%	18%	22%,	Naebe et al. [204]
CF/GO/epoxy	Compression molding technique	0.3 wt%	72%	66%	Pathak et al. [205]
f-GNPs/epoxy	Shear mixing	5.0 wt%	22.1%	Decreased continuously with GNPs content increases	Wang et al. [206]
GNP/carbon/epoxy	Three-roll mill	5wt.%	15%	–	Li et al. [207]
f-GO/carbon fabric/epoxy	VaRTM	0.3 wt%	–	29.7%	Shen et al. [208]

GO: graphene oxide; GNPs: graphene nanoplatelets; f-GNPs: functionalized Graphene nanoplatelets; GNP: graphite nanoplatelet; f-Gr: functionalized graphene; f-GNR: functionalized graphene nanoribbon; CF: carbon fiber; VaRTM: vacuum-assisted resin transfer molding process; RTM: resin transfer molding.

Figure 13.

(a) Stress–strain curves and (b) flexural modulus and strength of the various composite specimen; Reprinted with permission from [204].

Interlaminar shear strength (ILSS)

To determine the capability of a composite for resisting delamination damage, the interlaminar shear strength (ILSS) is considered as a critical parameter. Pathak et al. observed that the interlaminar shear strength (ILSS) of GO added (0.3%) carbon fiber/epoxy composites increased 25% compared to the pristine [205]. Zhang et al. [12] claimed that interlaminar shear strength (ILSS) was increased (12.7%) when GO sheets were added to the interfacial regions of carbon fiber/matrix composite. Another study reported that at 15 wt% of graphene oxide/polyaniline (60:1 weight ratio) in the carbon fiber/divinylbenzene/polyaniline, enhanced (76%) its ILSS properties [210]. Han et al. found that when the epoxy resin was loaded with 10 wt% GO, the interlaminar shear strength (ILSS) was improved (8.05%) [211]. Shen et al. [208] reported that the interlaminar shear strength (ILSS) of a carbon fabric/epoxy composite was enhanced (12.9%) by the optimal content of oriented GO (catalyst Fe₃O₄) as depicted in Figure 14. Qi et al. [212] studied the grafting of stiff p-phenylenediamine (PPD) and ethylenediamine (EDA) to the carbon fiber surface. For the grafted EDA and PPD carbon fibers, the ILSS properties were improved by 44.8% and 38.6%, respectively. The interlaminar shear strength (ILSS) of various graphene epoxy nanocomposites is presented in Table 5.

Figure 14.

Effect of orientation and contents of GO (catalyst Fe₃O₄) on the interlaminar shear strength of carbon fiber/epoxy composites; Reprinted with permission from [208].

Table 5.

Interlaminar shear strength (ILSS) of various graphene epoxy nanocomposites.

Type of sample	Preparation method	Optimum loading (wt%)	Interlaminar shear strength (ILSS) (MPa)	References
GO/CF/epoxy	Hand lay up	5 wt%	12.7%	Zhang et al. [12]
GO/CF/epoxy	VaRTM	0.2 mg/ml	47% increase for GOs coated CF,44% increase thermally annealed GOs coated CF. 41% increase Reduced exfoliated graphene oxide (rEGO)	Bhanuprakash et al. [174]
GNPs/CF/epoxy	Hand Lay up	3 wt%	19%	Qin et al. [177]
Silanized GO/CF/epoxy	Resin transfer molding	0.5 wt%	19%	Chen et al. [197]
GO/CF/epoxy	Compression molding technique	0.3 wt%	25%	Pathak et al. [205]
f-GO/carbon fabric/epoxy	VaRTM	0.3 wt%	12.9% increase for functionalization by Fe₃0₄ and 41% increase under the magnetic field orientation	Shen et al. [208]
Gr/CF/epoxy	Resin transfer molding	1 wt%	28.3 %	Chen et al. [213]
Graphitic carbon nitride /CF/epoxy	Vacuum bag molding	–	39.06%	Song et al. [214]
GO/CF/epoxy	VaRTM	0.25 g/L	55.6%	Jang et al. [215]

GO: graphene oxide; CF: carbon fiber; GNPs: graphene nanoplatelets; f-GNPs: functionalized graphene nanoplatelets; f-GO: functionalized graphene oxide; VaRTM: vacuum-assisted resin transfer molding process.

Interfacial shear strength (IFSS)

Interfacial shear strength (IFSS) between particle and matrix in nanocomposite is crucial property which influenced the fracture toughness of composite [215]. Numerous researchers modified fiber surfaces to enhance the interfacial shear strength of fiber composites by using various nanoscale surfactants such as carbon nanotubes and graphene [216]. Yao et al. explained that by designing the fiber/matrix interface, the addition of nanomaterials improved the interfacial properties of the carbon fiber/epoxy composites [28]. Chen et al. [197] studied silanized graphene oxide on fiber surfaces by employing physical deposition to form gradient interphase in the composite interface. The addition of 0.5 wt% silanized graphene oxide in composite enhanced the interfacial shear strength (60%), as shown in Figure 15. Zhang et al. [12] improved the interfacial properties of carbon fiber/epoxy composites by dispersing GO sheets (5 wt.%) in the fiber sizing. Beggs et al. [217] examined an aryl diazo-grafting methodology by applying reagent concentrations to modify of carbon fiber surfaces. A substantial rise in IFSS was noted in the resultant composites. Table 6 shows the interfacial shear strength of various graphene/epoxy nanocomposites.

Figure 15.

Interfacial shear strength (IFSS) of carbon fiber/epoxy composites with graphene nanosheets; Reprinted with permission from [197].

Table 6.

Interfacial shear strength of various graphene epoxy nanocomposites.

Type of sample	Preparation method	Optimum loading(wt%)	Interfacial shear strength (IFSS) MPa	References
GO/CF/epoxy	Hand lay up	7.5 wt%	70.9%	Zhang et al. [12]
GO/CF/epoxy	VaRTM	--	63.1%	Yao et al. [28]
GrNp/carbon/epoxy	Three-roll mill	5 wt%	18%	Li et al. [207]
Silanized GO/CF/epoxy	Resin transfer molding	0.5 wt%	60%	Chen et al. [197]
Graphitic carbon nitride /CF/epoxy	Vacuum bag molding	--	64.52%	Song et al. [214]
f-Graphite/epoxy	Mechanical mixing	0.5 wt%.	32 %	Lee et al. [216]
GO/CF-ECO/epoxy	VaRTM	25 mg/L	50%	Yuan et al. [218]

GO: graphene oxide; CF: carbon fiber; GrNp: graphite nanoparticle; f-Graphite: functionalized graphite; CF-ECO: carbon fiber of electrical conduction; VaRTM= vacuum-assisted resin transfer molding technique.

Interlaminar fracture toughness

Mode-I fracture toughness (G_IC)

The fracture behavior of the composites was affected by fiber sizing/coating, modification of matrix, fiber volume fraction, and stacking sequence [219]. Fracture toughness is an essential factor as it allows defining the energy absorption and damaging tolerance capability of a structure [220]. It was reported that graphene and its derivatives were more efficient for increasing mode-I fracture toughness of epoxy resin than carbon nanotube-incorporate epoxy resins [221]. The mode-I fracture toughness of the graphene/epoxy nanocomposite was improved (53%) compared to the MWCNTs composite [175]. It was identified that at 1 wt % loading of graphene oxide to an epoxy resin enhances its mode-I fracture toughness (28-111%) [18]. One of the another studies showed that mode-I fracture toughness (G_IC) was enhanced from 0.165 kJ/m² to 0.336 kJ/m² for a nanocomposite containing 0.5 wt.% of GNPs [222]. Galpaya et al. [223] observed that mode-I fracture toughness was improved about 50% with 0.1 wt. % GO loading to the epoxy. On the other hand, introducing functionalized graphene sheets in epoxy matrix increased its fracture toughness, fracture energy, and fatigue resistance, as illustrated in Figure 16 [224]. It is stated that fiber/matrix adhesion improvement by fiber surface treatment or sizing incorporated with graphene nanoplatelets resulted the improvement of mode-I and mode-II fracture toughness, interlaminar shear strength, and in-plane shear strength of the composites [225]. Another study reported that functionalization of graphene enhanced mode-1 fracture toughness of composites [200]. Figure 17 shows the graphene nanocomposites with the -COOH and -NH₂ functional groups and NH₂ functional group-containing graphene, which offered better fracture toughness compared to the -COOH functional group [200]. Table 7 shows the fracture toughness of various graphene/epoxy nanocomposites.

Figure 16.

Effect of various GNPs contents on fracture toughness and fracture energy of nanocomposites; Reprinted with permission from [224].

Figure 17.

Fracture toughness (mode I) of graphene/epoxy nanocomposites with different graphene loadings; Reprinted with permission from [200].

Table 7.

Fracture toughness of various graphene/epoxy nanocomposites.

Type of sample	Preparation method	Optimum loadingwt%	Critical stress intensity factor (K_IC) MPa-m^1/2	Plane strainstate fracture energy (G_IC) J/m²	References
GO/epoxy	Three-roll mill	1 wt%	63%	111%	Bortz et al. [18]
f-GNPs/epoxy	Three-roll mill	0.5 wt%	86%	–	Moghadam et al. [88]
RGO/epoxy	Mechanical mixing	0.2 wt%	52%	–	Tang et al. [90]
GO/CF/epoxy	VaRTM	0.25 mg/ml	–	14%	Bhanuprakash et al. [174]
f-GO/epoxy	Ball milling	0.10 wt%	39%	83%	Wan et al. [185]
f-GNPs/epoxy	Solution mixing	0.25 vol%	188%	202%	Meng et al. [191]
f-GNR epoxy	Ball milling	0.15 wt%	43%	–	Nadiv et al. [194]
GNPs/epoxy	Three-roll mill	1 wt%	33%	–	Imran and Shivakumar et al. [195]
f-GNPs/epoxy	Shear mixing	5.0 wt%	92.8%	–	Wang et al. [207]
Aligning GNPs/epoxy	Three-roll mill	1.08 vol%	–	900%	Wu et al. [226]
GWF/epoxy	Two step curing process	0.62 wt %	67%	–	Liu et al. [227]
f-GNP/epoxy	Mechanical mixing	0.25 wt%	22%	51%	Domun et al. [228]

GO: graphene oxide; GNPs: graphene nanoplatelets; f-GNPs: functionalized graphene nanoplatelets; CF: carbon fiber; VaRTM: vacuum-assisted resin transfer molding technique; f-GNR: functionalized graphene nanoribbon; RGO: reduced graphene oxide; GWF: graphene woven fiber.

Mode-II fracture toughness (G_IIC)

It was found that at 0.5 wt%, loadings of graphene nanoplatelets to epoxy exhibited a 41% enhancement on mode-II fracture toughness of graphene nanocomposite compared to the neat epoxy adhesive as shown in Figure 18 [229]. Domun et al. noticed that the fracture toughness of epoxy resin was enhanced by over 50% with the inclusion of 0.25 wt% addition plasma functionalized graphene nanoplatelets compared to the neat epoxy [228].

Figure 18.

Mode-II fracture toughness of graphene nanocomposites at different nano graphene content; Reprinted with permission from [229].

Thermal conductivity

Polymer composites possess poor thermal conductivity, and it has been a significant drawback of their end-use, especially in high performance required areas such as aerospace and defense. Graphene nanocomposites grip huge potentiality like the thermal interface materials (TIMs) for dissipating heat for electronic packages [230]. Graphene-associated material is a good candidate for generating advanced functional materials [231]. The thermal conductivity is calculating corresponding to the following equation (3):

K = α \times ρ \times C_{ρ}

(3)

Where K is the thermal conductivity (W m⁻¹K⁻¹), α is the thermal diffusivity (mm² s⁻¹), ρ is the density of the samples (gcm⁻³), and $C_{ρ}$ is the specific heat capacity (Jg⁻¹K⁻¹). The thermal conductivity of few-layer graphene is lower than that of single-layer graphene, which was 5000 Wm⁻¹K⁻¹ [149]. The thermal conductivity of the polymer improves by two orders of magnitude (from 0.2 to 20 W/mK) with the incorporation of graphene at 30 wt% as graphene-film, enhancing the thermal stability of the composite [232]. In another study, thermal conductivity was improved about 7 times from 200 Wm⁻¹ K⁻¹ to 1500 Wm⁻¹ K⁻¹ for panels spray-coated with carbon fiber composite using MWCNTs/GNPs hybrids [233]. Graphene-epoxy composite’s heat propagation is produced primarily because of acoustic phonons and electrons scattering activities. A high thermal conductivity enhancement (132%) was accomplished, adding only 4 wt.% of graphene, whereas 68% improvement for adding 2 wt.% of the graphene in composite was achieved [24]. Functionalization of graphene is an effective means to facilitate the improvement in thermal interface transport of the composite [234]. Shahil et al. [235] observed that if graphene and multilayer graphene were combined, this combination exhibited an enormously strong enhancement of thermal conductivity of the composite. They revealed that K ∼ 14 W/mK in the viable thermal grease via the addition of 2% of the optimized graphene-multilayer graphene nanocomposite mixture was obtained. The introduction of expanded graphite in polymers can also enhance the thermal conductivity of epoxy resins functionally [236]. Adding an organic phosphorous compound with GO showed the improvement of thermal stability and thermal conductivity of epoxy (30.8%) [237]. Thermal conductivity of graphene/epoxy nanocomposites increased by 20% (greater than pristine GNS/epoxy) and 267% (greater than pristine MWCNT/epoxy) by non-covalent functionalization with poly (glycidyl methacrylate) comprising localized pyrene groups (Py-PGMA) as exhibited in Figure 19 [238]. Table 8 presents thermal conductivity enhancement by various graphene/epoxy nanocomposites.

Figure 19.

An illustration of thermal conductivity of MWCNTs/epoxy, graphene/epoxy, and Py-PGMA–graphene; Reprinted with permission from [238].

Table 8.

Thermal conductivity enhancement by various graphene/epoxy nanocomposites.

Type of sample	Preparation method	Optimum loading (wt%)	% Increase in thermal conductivity (W/mK)	References
GNPs/epoxy	Solution mixing	5 wt%	115 %	Wang et al. [173]
GNPs/epoxy	Solution mixing	1 wt%	126%	Zakaria et al. [189]
GNPs/epoxy	three-roll mill	1 wt%	93%	Imran and Shivakumar et al. [195]
GNPs/epoxy	Shear mixing	5 wt%	133.6%	Wang et al. [206]
GNPs/epoxy	three-roll mill	1.08 vol%	60%	Wu et al. [226]
f-GNS/epoxy	Solution mixing	4 phr	800%	Teng et al. [238]
MGO/epoxy	Solution mixing	2 wt %	104.8%	Zhou et al. [239]
GNPs/epoxy	Solution mixing	8 wt%	627%	Wang et al. [240]
GNp/epoxy	ultrasonication	2.703 wt%	240%	Min et al. [241]
Graphite/epoxy	Solution mixing	12 wt.%	350%	Tien et al. [242]

GNPs: Graphene nanoplatelets; MGO: Modified graphene oxides; GO: Graphene oxide; GNp: Graphite nanoparticle; f-GNS: Functionalized graphene nanosheets.

Electrical conductivity

When graphene is used as filler to the polymer matrix, it improves the electrical conductivity of the composite because of its good conductivity and aspect ratio. A conductive network is formed in the polymer matrix when graphene is added. The conductivity is expressed as a function σ_c filler loading can be termed by employing an easy power-law expression, i.e.,

σ c = σ f (φ - φ c) t

(4)

Where σ_c is the volume fraction of the filler, φ_c is the percolation threshold, σ_f is the conductivity of the filler, and t is a scaling exponent. Electrical functioning relies on some factors such as the processing and dispersion, inherent features of the filler, aggregation, and filler orientation and alignment [243]. Stankovich et al. [244] made graphene-based conductive polymer nanocomposites altered with isocyanate and reduced by hydrazine hydrate process made graphene to show good electrical conductivity. It was shown that the percolation threshold value was only 0.1 vol%, near to the lowest value of the single-walled carbon nanotube which is sufficient for many electrical applications. Improvement of the electrical conductivity of epoxy from 4.3x10⁻¹⁵ to 2.6x10⁻⁶ S/m at the percolation threshold of graphene was 1.0 wt% [195]. At 5 mg/ml of graphene concentration, the electrical conductivity reached 0.70 S/cm, achieving orders of magnitude enhancement of the carbon/epoxy nanocomposites as depicted in Figure 20 [245]. Table 9 presents the electrical conductivity of various graphene/epoxy nanocomposites.

Figure 20.

The electrical conductivity of carbon foam/epoxy/reduced graphene oxide and melamine foam modified graphene oxide/epoxy composites with different GO concentration; Reprinted with permission from [245].

Table 9.

Electrical conductivity of various graphene/epoxy nanocomposites.

Type of sample	Preparation method	Filler loading (wt%)	Electrical conductivity (S/cm)	References
GO/CF/epoxy	VaRTM	0.25 mg/ml	127% increase thermally annealed GOs coated CF90% increase Reduced exfoliated graphene oxide (rEGO)	Bhanuprakash et al. [174]
GNPs/CFs/epoxy	Hand lay up	3 wt %	165%	Qin et al. [178]
f-GNPs/epoxy	Mechanical mixing	2.7 vol%	1.0 × 10⁻⁴ S/m,	Tang et al. [187]
f-GNPs/epoxy	Solution blending	0.31 vol%.	1200 S/cm	Meng et al. [191]
G-Np/CF/epoxy	Three-roll milling	5 wt %	0.60 S/m	Li et al. [207]
GWF/epoxy	Two-step curing process	0.62 wt %	0.18 S/cm	Liu et al. [227]
G-P/epoxy	Mechanical mixing	1 wt%	1.6 × 10⁻⁶ S/cm	Fan et al. [246]
Graphene/ZnO tetrapod whiskers/epoxy	Solution blending	4 wt %	27.2 S/m	Jiang et al. [247]

GO: graphene oxide; CF: carbon fibre; f-GNPs = functionalized graphene nanoplatelets; G-P: graphite platelet; G-Np: graphite nano particle; f-Gr: functionalized graphene; GWF: graphene woven fiber; VaRTM: vacuum-assisted resin transfer molding technique.

Application areas of graphene and graphene nanocomposites

Graphene can be employed in a broad range of areas comprising engineering, electronics, medicine, energy storage, industrial, household design, biomedical applications, drug delivery and tissue engineering [248,249]. Some of the potential end-uses of nanographene composites were provided in this section.

Industrial structural components

Graphene integrated fiber-reinforced composites is one of the candidate for structural materials in the aviation and automotive industries. Recently, graphene is used for the Airbus A350 horizontal tail leading edge. Graphene increases the mechanical properties of the leading edge, enabling plane parts lighter and thinner, enhanced aerodynamics, and reduces the consumption of fuel across the lifespan of the airplane. Carbon fiber-reinforced graphene nanocomposites have numerous applications, for example, improved gas barrier properties, surface technology, fuel tank and protective coating in the aerospace industry [1,139]. The automotive industry worldwide is faced with the challenges of carbon dioxides emissions reduction, safety, and energy efficiency. Graphene-based composite materials can be used for energy-efficient and safe vehicles (EESVs) [250]. Introducing graphene-based smart devices (combined with wirings, sensors, switches), transparent heaters defogging/deicing systems in the automotive areas are predictable to reduce fuel consumption and subsequently the CO₂ emission at various stages [251]. The greatest effect will be in the upcoming future is in the construction area by adding graphene to concrete.

Electronics

Graphene is a material with several exceptional characteristics and can establish the next generation of electronics smarter transistors, semiconductors, bendable phones, and other electronics. Graphene's exclusive properties of lightest, strongest, and higher conductivity have led to research into its applications as semiconductors [252]. Graphene has novel functionalities, including ultracapacitors [253], transparent conducting electrodes [81], optical displays, printing circuits and electrical devices [254]. Generally, graphene nanoribbons (GNRs) provide field-effect transistor (FET) applications with very high electrical conductivity and flexibility [255]. Graphene and its derivatives are widely employed in light-emitting diode (LED), FET, memory, and photovoltaic devices [256], electroluminescent devices, gate dielectrics [257], and touch panel devices. There is a great concern in the commercial adaptation of highly electrical quality for electronics applications of large-area graphene, involving high-frequency terahertz (THz) electronics [258] and transparent and resilient electrodes for touchscreen displays and solar cells [259]. Graphene nanocomposite actuators are employed in the micro-electro-mechanical system (MEMS)-based micro-grippers [260], photonic switches, soft robotics, plastic motors, and adaptive micro-mirrors [261]. One of the example is that bilayer actuator made with 30 wt% graphene composites is used to construct a beluga whale soft robot [262].

Energy storage

Graphene-based nanocomposites can be used to replace traditional rechargeable lithium batteries in energy storage applications because they can retain energy and power density [263]. In the last decades, rigorous research has been going on to implement Li+ ions into the lattice of graphite, and recently, electrochemical energy storage capacity in graphene-based systems attains much attention for research [264]. Graphene supercapacitors can be charged very rapidly, capable of storing a vast quantity of electricity. Lithium-ion batteries incorporating graphene could be employed as electrically powered vehicles in smartphones, laptops but at a minimal size and weight.

Sensors

Graphene-based e-textile have been used as sensors for various purposes such as electrodes for heart rate monitoring, strain sensor, alcohol sensor, glucose sensor, CO₂ and NO₂ gas sensor, and temperature sensors [265,266]. The GO-based fabric has been used as wearable gas and alcohol vapors sensors and exhibited promising results [267]. Graphene-reinforced polymer-based composite biosensors benefit due to higher sensitivity, speedy response time, permanency, and a low limit of detection (LOD) [268]. The monitoring, informing, and prompt detection of toxic gases [269] become more prevalent to avoid or lessen accidents that involve poisoning and blasts. Graphene-reinforced polymer nanocomposite material can be used for various sensor applications (e.g., temperature, biomolecules, pressure, pH, and strain sensors) owing to their 2 D (atom-thick) conjugated structures, higher conductivity, and larger surface areas [270].

Biomedical

Graphene nanocomposites have been drawn attention to the biomedical field. Recent advancement of graphene in biomedical applications gives us several biomedical gadgets, for example, deep brain stimulators [271] and blood glucose sensors [272]. In addition, graphene has been used as a nanomaterial in tissue engineering [273], gene therapy [274], cancer treatment and diagnosis [275], cell imaging [276], and bioelectronics [277]. The antimicrobial activity and drug delivery potential of the graphene nanocomposite have been also discovered. Graphene has been applied with polystyrene, nylon-6,6, polyurethanes, poly(caprolactone) and poly (methyl methacrylate) in the biomedical field [278]. The application of graphene in this area has prominence on the skillful treating methods to construct the preferred structures and membranes.

Textile industries

Graphene is a promising aspirant as the functional element in smart textiles, including wearable e-textiles, due to its superior properties and its integration into synthetic and natural textiles that can be utilized for the groundwork of multifunctional textiles for larger applications [279]. By modifying the fabrics with graphene can enhance properties like mechanical strength, antibacterial, flame resistance, photocatalytic, conductivity, and UV protection of the fabric and be used as protective clothing for healthcare workers, firefighters, laborers, and military personnel [280]. Several attempts have been made to mingle textile-based sensors into clothes, such as inkjet-printed graphene composite inks for wearable textiles applications that offer mass customization, lessening material waste, high precision printing, and compatibility with various substrates [281]. Gao et al. [282] developed porous activate cotton textile (ACT) tubular fibers embedded with NiS₂ nanobowls and coated with graphene to prepare flexible electrodes for Li-ions batteries and show its practical application for flexible energy storage devices. Lu et al. [283] prepared highly conductive graphene-coated silk fabrics (sheet resistance is 1.5 kΩsq⁻¹), and fibers (the electrical conductivity is 3595 Sm⁻¹) that are promising as the functional supporting matrix and conducting fabrics/wires in future wearable electronics. Another study explored the fabrication of electroconductive cotton textiles by using graphene, and these fabrics have high potential to apply in advanced applications such as smart e-textiles [284]. Tang et al. [285] fabricated multifunctional cotton fabric with high electrical conductivity and ultra-strong UV radiation protection properties using polyaniline (PANI)-GO nanocomposites. Conclusively, it is identified that graphene nanocomposites show significant advantages in the textile area and shine a bright light on the fabrication of functional textiles.

Conclusion

In this paper, graphene and graphene nanocomposites were reviewed. The synthesis process of graphene and their fabrication, properties, performance, and potential applications have been identified.

It was found that several synthesis methods for nanographene were developed as mechanical exfoliation, liquid-phase exfoliation, chemical vapor deposition, and epitaxial growth. On the other hand, the fabrication of graphene-based nanocomposites includes solution mixing technique, in-situ polymerization, melt blending, and electrospinning. In addition, fabrication methods on nanographene dispersed fiber/matrix composites includes resin transfer molding and vacuum-assisted resin transfer molding.

The growth of graphene/matrix and fiber/matrix graphene nanocomposites opens a new paradigm where matrix and fiber can be modified to upsurge the properties of advanced composites. The critical properties of graphene added nanocomposites were discussed. These include in-plane and out-of-plane thermo-mechanical, electrical, and optical properties. It was realized that graphene and graphene nanocomposites represented potential materials in advanced engineering applications, including soft robotics, microelectronics, energy storage, supercapacitor, transparent electrodes, biological and biomedical areas, biosensors and wearable e-textiles.

Future research probably carries on the defect-free 2 D graphene plate, surface functionalization of nanographene to improve the structure-property interaction of nanocomposite and cost-effective fabrication techniques.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Kadir Bilisik

Mahmuda Akter

References

Al Mahmud

Radue

Chinkanjanarot

, et al. Multiscale modeling of carbon fiber-graphene nanoplatelet-epoxy hybrid composites using a reactive force field. Compos B Eng 2019; 172: 628–635.

Kausar

Rafique

Muhammad

Aerospace application of polymer nanocomposite with carbon nanotube, graphite, graphene oxide, and nanoclay. Polym Plast Technol Eng 2017; 56: 1438–1456.

Camargo

PHC

Satyanarayana

Wypych

Nanocomposites: synthesis, structure properties and new application opportunities. Mat Res 2009; 12: 1–39.

Dunlop

Bissessur

Nanocomposites based on graphene analogous materials and conducting polymers: a review. J Mater Sci 2020; 55: 6721–6753.

Winey

Vaia

RA.

Polymer nanocomposites. MRS Bull 2007; 32: 314–322.

Young

Liu

Kinloch

, et al. The mechanics of reinforcement of polymers by graphene nanoplatelets. Compos Sci Technol 2018; 154: 110–116.

Pradhan

Chattopadhyay

Ratna

Graphene nanoplatelets in polychloroprene matrix: an insight to dispersion with a special emphasize to electro‐mechanical properties. Polym Compos 2019; 40: E1871–E1883.

Young

Kinloch

Gong

, et al. The mechanics of graphene nanocomposites: a review. Compos Sci Technol 2012; 72: 1459–1476.

King

Klimek

Miskioglu

, et al. Mechanical properties of graphene nanoplatelet/epoxy composites. J Appl Polym Sci 2013; 128: 4217–4223.

10.

Mohan

Lau

K-t

Hui

, et al. Graphene-based materials and their composites: a review on production, applications and product limitations. Compos B Eng 2018; 142: 200–220.

11.

Srivastava

Gries

Veit

, et al. Effect of nanomaterial on mode I and mode II interlaminar fracture toughness of woven carbon fabric reinforced polymer composites. Eng Fract Mech 2017; 180: 73–86.

12.

Zhang

Fan

Yan

, et al. Interfacial microstructure and properties of carbon fiber composites modified with graphene oxide. ACS Appl Mater Interfaces 2012; 4: 1543–1552.

13.

Liu

Yan

, et al. Improving interfacial properties of hierarchical reinforcement carbon fibers modified by graphene oxide with different bonding types. Compos A Appl Sci Manuf 2018; 107: 616–625.

14.

Saboori

Ayatollahi

MR.

Experimental fracture study of MWCNT/epoxy nanocomposites under the combined out-of-plane shear and tensile loading. Polym Test 2017; 59: 193–202.

15.

Eskizeybek

Yar

Avcı

CNT-PAN hybrid nanofibrous mat interleaved carbon/epoxy laminates with improved mode I interlaminar fracture toughness. Compos Sci Technol 2018; 157: 30–39.

16.

Thostenson

Ren

Chou

T-W.

Carbon nanotubes and their composites: a review. Compos Sci Technol 2001; 61: 1899–1912.

17.

Tang

Gao

, et al. Application of graphene as filler to improve thermal transport property of epoxy resin for thermal interface materials. Int J Heat Mass Transf 2015; 85: 420–429.

18.

Bortz

Heras

Martin-Gullon

Impressive fatigue life and fracture toughness improvements in graphene oxide/epoxy composites. Macromolecules 2012; 45: 238–245.

19.

Lawal

AT.

Graphene-based nano composites and their applications. A review. Biosens Bioelectron 2019; 141: 111384.

20.

Cataldi

Athanassiou

Bayer

Graphene nanoplatelets-based advanced materials and recent progress in sustainable applications. Appl Sci 2018; 8: 1438.

21.

Geim

Novoselov

KS.

The rise of graphene. Nat Mater 2007; 6: 183–191.

22.

Geim

AK.

Graphene: status and prospects. Science 2009; 324: 1530–1534.

23.

Ozkan

Handbook of graphene, volume 4: composites. USA: Scrivener Publishing, 2019.

24.

Jarosinski

Rybak

Gaska

, et al. Enhanced thermal conductivity of graphene nanoplatelets epoxy composites. Mater Sci-Poland 2017; 35: 382–389.

25.

Abdullah

Ansari

MNM.

Mechanical properties of graphene oxide (GO)/epoxy composites. HBRC J 2015; 11: 151–156.

26.

Falkovsky

LA.

Optical properties of graphene. J Phys: Conf Ser 2008; 129: 012004.

27.

Vargas-Bernal

State-of-the-art electronic devices based on graphene. In: Kar A (ed.) Nanoelectronics and materials development. London: Intech Open 2016, pp. 1–21.

28.

Yao

Gao

Jiang

, et al. Comparison of carbon nanotubes and graphene oxide coated carbon fiber for improving the interfacial properties of carbon fiber/epoxy composites. Compos B Eng 2018; 132: 170–177.

29.

Karim

Afroj

Tan

, et al. All inkjet-printed graphene-silver composite ink on textiles for highly conductive wearable electronics applications. Sci Rep 2019; 9: 8035.

30.

Bonaccorso

Lombardo

Hasan

, et al. Production and processing of graphene and 2D crystals. Mater Today 2012; 15: 564–589.

31.

Novoselov

Geim

Morozov

SV.

Electric field effect in atomically thin carbon films. Science 2004; 306: 666–669.

32.

Park

Ruoff

RS.

Chemical methods for the production of graphenes. Nat Nanotechnol 2009; 4: 217–224.

33.

Ramachandran

Felix

Joshi

, et al. Synthesis of graphene platelets by chemical and electrochemical route. Mater Res Bull 2013; 48: 3834–3842.

34.

Allen

Tung

Kaner

RB.

Honeycomb carbon: a review of graphene. Chem Rev 2010; 110: 132–145.

35.

Aparna

Sivakumar

Balakrishnan

, et al. An effective route to produce few-layer graphene using combinatorial ball milling and strong aqueous exfoliants. J Renew Sust Energ Rev 2013; 5: 033123.

36.

Rollings

Gweon

G-H

Zhou

, et al. Synthesis and characterization of atomically thin graphite films on a silicon carbide substrate. J Phys Chem Solids 2006; 67: 2172–2177.

37.

Pradeepkumar

Amjadipour

Mishra

, et al. p-Type epitaxial graphene on cubic silicon carbide on silicon for integrated silicon technologies. ACS Appl Nano Mater 2020; 3: 830–841.

38.

Berger

Song

, et al. Electronic confinement and coherence in patterned epitaxial graphene. Science 2006; 312: 1191–1196.

39.

Qing

Hou

Stehle

, et al. Chemical vapor deposition synthesis of graphene films. APL Mater 2019; 7: 020903.

40.

Levchenko

Volotskova

Shashurin

, et al. The large-scale production of graphene flakes using magnetically-enhanced arc discharge between carbon electrodes. Carbon 2010; 48: 4570–4574.

41.

Yan

Wang

, et al. Controllable ionic liquid-assisted electrochemical exfoliation of carbon fibers for the green and large-scale preparation of functionalized graphene quantum dots endowed with multicolor emission and size tunability. J Mater Chem C 2017; 5: 6092–6100.

42.

Das

Ghosh

Sarkar

, et al. Facile synthesis of multi-layer graphene by electrochemical exfoliation using organic solvent. Nanotechnol Rev 2018; 7: 497–508.

43.

Xin

Hwang

Kim

, et al. A graphene sheet exfoliated with microwave irradiation and interlinked by carbon nanotubes for high-performance transparent flexible electrodes. Nanotechnology 2010; 21: 405201.

44.

Xie

Zhou

Huang

Advances in microwave-assisted production of reduced graphene oxide. Front Chem 2019; 7: 355.

45.

Dato

Radmilovic

Lee

, et al. Substrate-free gas-phase synthesis of graphene sheets. Nano Lett 2008; 8: 2012–2016.

46.

Münzer

Xiao

Sehlleier

, et al. All gas-phase synthesis of graphene: characterization and its utilization for silicon-based lithium-ion batteries. Electrochim Acta 2018; 272: 52–59.

47.

Koehler

Stark

WJ.

Organic synthesis on graphene. Acc Chem Res 2013; 46: 2297–2306.

48.

Ebajo

Jr Santos

CRL

Alea

, et al. Regenerable acidity of graphene oxide in promoting multicomponent organic synthesis. Sci Rep 2019; 9: 15579.

49.

Choucair

Thordarson

Stride

JA.

Gram-scale production of graphene based on solvothermal synthesis and sonication. Nat Nanotechnol 2009; 4: 30–33.

50.

Zhou

Cheng

Q-Y

Han

B-H.

Solvothermal synthesis of homogeneous graphene dispersion with high concentration. Carbon 2011; 49: 3920–3927.

51.

Kosynkin

Higginbotham

Sinitskii

, et al. Longitudinal unzipping of carbon nanotubes to form graphene nanoribbons. Nature 2009; 458: 872–876.

52.

Jiao

Zhang

Wang

, et al. Narrow graphene nanoribbons from carbon nanotubes. Nature 2009; 458: 877–880.

53.

Luong

Bets

Algozeeb

, et al. Gram-scale bottom-up flash graphene synthesis. Nature 2020; 577: 647–651.

54.

Choi

Lahiri

Seelaboyina

, et al. Synthesis of graphene and its applications: a review. Crit Rev Solid State Mater Sci 2010; 35: 52–57.

55.

Novoselov

Jiang

Schedin

, et al. Two-dimensional atomic crystals. Proc Natl Acad Sci USA 2005; 102: 10451–10453.

56.

Chen

Duan

Chen

Continuous mechanical exfoliation of graphene sheets via three-roll mill. J Mater Chem 2012; 22: 19625.

57.

Narayan

Kim

SO.

Surfactant mediated liquid phase exfoliation of graphene. Nano Converg 2015; 2: 20.

58.

Ciesielski

Samori

Graphene via sonication assisted liquid-phase exfoliation. Chem Soc Rev 2014; 43: 381–398.

59.

Liu

Gao

Preparation of few-layer and single-layer graphene by exfoliation of expandable graphite in supercritical N,N-dimethylformamide. J Supercrit Fluids 2012; 63: 99–104.

60.

Quintana

Grzelczak

Spyrou

, et al. Production of large graphene sheets by exfoliation of graphite under high power ultrasound in the presence of tiopronin. Chem Commun 2012; 48: 12159–12161.

61.

Suslick

KS.

Sonochemical preparation of functionalized graphenes. J Am Chem Soc 2011; 133: 9148–9151.

62.

Quintana

Tapia

Prato

Liquid-phase exfoliated graphene: functionalization, characterization, and applications. Beilstein J Nanotechnol 2014; 5: 2328–2338.

63.

Bordes

Morcos

Bourgogne

, et al. Dispersion and stabilization of exfoliated graphene in ionic liquids. Front Chem 2019; 7: 223.

64.

Campos-Delgado

Botello-Méndez

Algara-Siller

, et al. CVD synthesis of mono- and few-layer graphene using alcohols at low hydrogen concentration and atmospheric pressure. Chem Phys Lett 2013; 584: 142–146.

65.

Cai

Colombo

, et al. Evolution of graphene growth on Ni and Cu by carbon isotope labeling. Nano Lett 2009; 9: 4268–4272.

66.

Kim

M-S

Woo

J-M

Geum

D-M

, et al. Effect of copper surface pre-treatment on the properties of CVD grown graphene. AIP Adv 2014; 4: 127107.

67.

Vinogradov

Zakharov

Kocevski

, et al. Formation and structure of graphene waves on Fe(110). Phys Rev Lett 2012; 109: 026101.

68.

Sutter

Sadowski

Sutter

Graphene on Pt(111): growth and substrate interaction. Phys Rev B 2009; 80: 245411.

69.

Zhang

Yuan

, et al. Fast growth of inch-sized single-crystalline graphene from a controlled single nucleus on Cu-Ni alloys. Nat Mater 2016; 15: 43–47.

70.

Kim

Song

Lee

, et al. Low-temperature synthesis of graphene on nickel foil by microwave plasma chemical vapor deposition. Appl Phys Lett 2011; 98: 263105.

71.

Magnuson

Venugopal

, et al. Graphene films with large domain size by a two-step chemical vapor deposition process. Nano Lett 2010; 10: 4328–4334.

72.

Plutnar

Pumera

Sofer

The chemistry of CVD graphene.

J Mater Chem C 2018; 6: 6082–6101.

73.

Kalita

Matsushima

Uchida

, et al. Graphene constructed carbon thin films as transparent electrodes for solar cell applications. J Mater Chem 2010; 20: 9713–9717.

74.

Shi

Tokarska

, et al. Substrate developments for the chemical vapor deposition synthesis of graphene. Adv Mater Interfaces 2020; 7: 1902024.

75.

Muñoz

Gómez-Aleixandre

Review of CVD synthesis of graphene. Chem Vap Deposition 2013; 19: 297–322.

76.

Gao

Zhang

, et al. Thermal chemical vapor deposition grown graphene heat spreader for thermal management of hot spots. Carbon 2013; 61: 342–348.

77.

Tan

Wang

Guo

Thermal growth of graphene: a review. Coatings 2018; 8: 40.

78.

Malesevic

Vitchev

Schouteden

, et al. Synthesis of few-layer graphene via microwave plasma-enhanced chemical vapour deposition. Nanotechnology 2008; 19: 305604.

79.

Ahmed

Kishi

Sugita

, et al. Graphene synthesis by thermal chemical vapor deposition using solid precursor. J Mater Sci: Mater Electron 2013; 24: 2151–2155.

80.

Rockett

Chemical vapor deposition. The materials science of semiconductors. Boston, MA: Springer US, 2008, pp.573–609.

81.

Kalita

Wakita

Umeno

Low temperature growth of graphene film by microwave assisted surface wave plasma CVD for transparent electrode application. RSC Adv 2012; 2: 2815–2820. [CrossRef][10.1039/c2ra00648k]

82.

Bhuyan

MSA

Uddin

Islam

, et al. Synthesis of graphene. Int Nano Lett 2016; 6: 65–83.

83.

Mullin

JB.

Single crystal growth II: epitaxial growth. In: Miller LS and Mullin JB (eds) Electronic materials: from silicon to organics. Boston, MA: Springer US, 1991, pp.127–142.

84.

Berger

Song

, et al. Ultrathin epitaxial graphite: 2D electron gas properties and a route toward graphene-based nanoelectronics. J Phys Chem B 2004; 108: 19912–19916.

85.

Mishra

Boeckl

Motta

, et al. Graphene growth on silicon carbide: a review. Phys Status Solidi A 2016; 213: 2277–2289.

86.

Edwards

Coleman

KS.

Graphene synthesis: relationship to applications. Nanoscale 2013; 5: 38–51.

87.

Gupta

Placidi

Hogan

, et al. The transition from 3C SiC(111) to graphene captured by ultra high vacuum scanning tunneling microscopy. Carbon 2015; 91: 378–385.

88.

Ahmadi-Moghadam

Sharafimasooleh

Shadlou

, et al. Effect of functionalization of graphene nanoplatelets on the mechanical response of graphene/epoxy composites. Mater Des 2015; 66: 142–149.

89.

You

Feng

Yang

, et al. Preparation of high concentration graphene dispersion with low boiling point solvents. J Nanopart Res 2019; 21: 19.

90.

Tang

L-C

Wan

Y-J

Yan

, et al. The effect of graphene dispersion on the mechanical properties of graphene/epoxy composites. Carbon 2013; 60: 16–27.

91.

Kausar

Technical viewpoint on polystyrene/graphene nanocomposite. J Thermoplast Compos Mater. Epub ahead of print 24 February 2020. DOI: 10.1177/0892705720907653.

92.

Kuan

Chen

, et al. Preparation, thermal stability and electrical properties of PMMA/functionalized graphene oxide nanosheets composites. Mater Chem Phys 2012; 134: 677–685.

93.

Kuila

Khanra

Mishra

, et al. Functionalized-graphene/ethylene vinyl acetate co-polymer composites for improved mechanical and thermal properties. Polym Test 2012; 31: 282–289.

94.

Wang

Chen

, et al. Enhancing dielectric properties of poly(vinylidene fluoride)-based hybrid nanocomposites by synergic employment of hydroxylated BaTiO₃ and silanized graphene. Polym Plast Technol Eng 2016; 55: 1595–1603.

95.

Duan

, et al. Structural effects of residual groups of graphene oxide on poly(ε-Caprolactone)/graphene oxide nanocomposite. Crystals 2018; 8: 270.

96.

Yun

Bae

Kim

, et al. Reinforcing effects of adding alkylated graphene oxide to polypropylene. Carbon 2011; 49: 3553–3559.

97.

Tang

L-C

Zhao

Guan

L-Z.

Graphene/polymer composite materials: processing, properties and applications. In: Bafekrpour E (ed) Advanced composite materials: properties and applications Warsaw, Poland: De Gruyter Open Poland, 2017, pp.349–419.

98.

Phiri

Gane

Maloney

TC.

General overview of graphene: production, properties and application in polymer composites. Mater Sci Eng B 2017; 215: 9–28.

99.

Chen

G-H

D-J

Weng

W-G

, et al. Preparation of polystyrene–graphite conducting nanocomposites via intercalation polymerization. Polym Int 2001; 50: 980–985.

100.

Wang

D-W

Zhao

, et al. Fabrication of graphene/polyaniline composite paper via in situ anodic electropolymerization for high-performance flexible electrode. ACS Nano 2009; 3: 1745–1752.

101.

Guo

Bao

Song

, et al. Situ polymerization of graphene, graphite oxide, and functionalized graphite oxide into epoxy resin and comparison study of on-the-flame behavior. Ind Eng Chem Res 2011; 50: 7772–7783.

102.

Ren

Zhu

Ren

, et al. In situ polymerization of graphene oxide and cyanate ester-epoxy with enhanced mechanical and thermal properties. Appl Surf Sci 2014; 316: 549–557.

103.

Yin

Wang

Lin

, et al. Polyacrylonitrile/graphene composite as a precursor to a sulfur-based cathode material for high-rate rechargeable Li–S batteries. Energy Environ Sci 2012; 5: 6966–6972.

104.

Wang

Tong

Yang

J-C

, et al. Improved strength and toughness of semi-aromatic polyamide 6T-co-6(PA6T/6)/GO composites via in situ polymerization. Compos Sci Technol 2019; 175: 6–17.

105.

Chee

Lim

Huang

, et al. Nanocomposites of graphene/polymers: a review. RSC Adv 2015; 5: 68014–68051.

106.

Kim

Miura

Macosko

CW.

Graphene/polyurethane nanocomposites for improved gas barrier and electrical conductivity. Chem Mater 2010; 22: 3441–3450.

107.

Shi

, et al. Polyamide 6/graphene oxide-g-hindered phenol antioxidant nano-composites: intercalation structure and synergistic thermal oxidative stabilization effect. Compos B Eng 2019; 162: 11–20.

108.

Hsiao

Liao

Lin

, et al. Preparation and characterization of polypropylene-graft-thermally reduced graphite oxide with an improved compatibility with polypropylene-based nanocomposite. Nanoscale 2011; 3: 1516–1522.

109.

Zhang

H-B

Zheng

W-G

Yan

, et al. Electrically conductive polyethylene terephthalate/graphene nanocomposites prepared by melt compounding. Polymer 2010; 51: 1191–1196.

110.

Luan

Shen

, et al. Encouraging mechanical reinforcement in polycarbonate nanocomposite films via incorporation of melt blending-prepared polycarbonate-graft-graphene oxide. Appl Phys A 2019; 125: 1–7.

111.

Lyu

J-Y

Chen

, et al. Fabrication of high-performance graphene oxide doped PVDF/CuO/Al nanocomposites via electrospinning. Chem Eng J 2019; 368: 129–137.

112.

Dias

Dip

RMM

Souza

DHS

, et al. Electrospun nanofibers of poly(lactic acid)/graphene nanocomposites. J Nanosci Nanotechnol 2017; 17: 2531–2540.

113.

Thenmozhi

Dharmaraj

Kadirvelu

, et al. Electrospun nanofibers: new generation materials for advanced applications. Mater Sci Eng B 2017; 217: 36–48.

114.

Wahab

Razak

SIA

Azmi

, et al. Electrospun graphene oxide-based nanofibres. In: Silva A and Carabineiro S (eds) Advances in carbon nanostructures. London: Intech Open, 2016, pp. 101–120.

115.

Park

Lee

Kim

, et al. Conducting polymer nanofiber mats via combination of electrospinning and oxidative polymerization. Polymer 2013; 54: 4155–4160.

116.

Garg

Bowlin

GL.

Electrospinning jets and nanofibrous structures. Biomicrofluidics 2011; 5: 13403.

117.

Bhardwaj

Kundu

SC.

Electrospinning: a fascinating fiber fabrication technique. Biotechnol Adv 2010; 28: 325–347.

118.

Abdali

Ajji

Preparation of electrospun nanocomposite nanofibers of polyaniline/poly(methyl methacrylate) with amino-functionalized graphene. Polymers (Basel) 2017; 9: 453.

119.

Albañil-Sanchez

Romo-Uribe

Flores

, et al. Electrospun nylon-graphene nanocomposites synthesis and microstructure. MRS Proc 2012; 1453: 1–8.

120.

Bagheri

Mahmoodzadeh

Graphene nanocomposites: synthesis, characterization and mechanical properties of electrospun nanofibers. J Inorg Organomet Polym Mater 2020; 30: 1566–1577.

121.

Ehteshami

Feizbakhsh

Mohsen Sarrafi

, et al. An electrospun polyamide/graphene oxide nanocomposite as a novel fiber coating. Anal Meth 2018; 10: 2123–2128.

122.

Ruan

Guo

Tang

, et al. Improved thermal conductivities in polystyrene nanocomposites by incorporating thermal reduced graphene oxide via electrospinning-hot press technique. Compos Commun 2018; 10: 68–72.

123.

Rajak

Pagar

Menezes

, et al. Fiber-reinforced polymer composites: manufacturing, properties, and applications. Polymers (Basel) 2019; 11: 1667.

124.

Bilisik

Multiaxis 3D weaving: comparison of developed two weaving methods (tube-rapier weaving versus tube-carrier weaving) and effects of bias yarn path to the preform properties. Fibers Polym 2010; 11: 104–114.

125.

Bilisik

Sapanci

Experimental determination of fracture toughness properties of nanostitched and nanoprepreg carbon/epoxy composites. Eng Fract Mech 2018; 189: 293–306.

126.

Bilisik

Erdogan

Sapancı

Flexural behavior of 3D para-aramid/phenolic/nano (MWCNT) composites. RSC Adv 2018; 8: 7213–7224.

127.

Akovali

Handbook of composite fabrication. Shorpshire, UK: Rapra Publishing, 2001, p.196.

128.

Hollaway

Handbook of polymer composites for engineers. Amsterdam, The Netherlands: Woodhead Publishing Limited, 1994, p.336.

129.

Crutchlow

Changing from open to closed moulding. Reinf Plast 2004; 48: 40–41.

130.

Mazumdar

SK.

Composites manufacturing materials, product, and process engineering. Boca Raton: CRC Press, 2002, p.396.

131.

Middleton

Composites: manufacture and application. In: Goodship V (ed) Design and manufacture of plastic components for multifunctionality 2016, pp.53–101. Cambridge, UK: Elsevier.

132.

Song

Vacuum assisted resin transfer molding (VARTM): model development and verification. Blacksburg, VA: Virginia Polytechnic Institute and State University, 2003.

133.

Sun

Xiao

Tao

, et al. Preparation of high-performance carbon fiber-reinforced epoxy composites by compression resin transfer molding. Materials (Basel) 2018; 12: 13.

134.

Mallick

PK.

Processing of polymer matrix composites. Boca Raton: CRC Press, Taylor & Francis Group, 2018, p.356.

135.

Hsiao

Heider

Vacuum assisted resin transfer molding (VARTM) in polymer matrix composites. In: Advani S and Hsiao K-T (eds) Manufacturing techniques for polymer matrix composites (PMCs) 2012, pp.310–347. Cambridge, UK: Elsevier.

136.

Bilisik

Karaduman

Sapanci

Tensile properties of nanoprepreg/nanostitched 3D carbon/epoxy MWCNTs composites. Mech Mater 2019; 128: 11–23.

137.

Bilisik

Karaduman

Sapanci

Flexural characterization of 3D prepreg/stitched carbon/epoxy/multiwalled carbon nanotube preforms and composites. J Compos Mater 2019; 53: 563–577.

138.

Lee

Kim

Shim

BS.

Graphene: an emerging material for biological tissue engineering. Carbon Lett 2013; 14: 63–75.

139.

Lee

Wei

Kysar

, et al. Measurement of the elastic properties and intrinsic strength of monolayer graphene. Science 2008; 321: 385–388.

140.

Zandiatashbar

Lee

, et al. Effect of defects on the intrinsic strength and stiffness of graphene. Nat Commun 2014; 5: 3186.

141.

Tsoukleri

Parthenios

Papagelis

, et al. Subjecting a graphene monolayer to tension and compression. Small 2009; 5: 2397–2402.

142.

Lee

Wei

, et al. Elastic and frictional properties of graphene. Phys Status Solidi B 2009; 246: 2562–2567.

143.

Wang

Yan

and Li M. Graphene nanocomposites. In: Hu N (ed) Composites and their properties. London: Intech Open, 2012, pp. 17–36.

144.

Ebrahimi

Heidari

A review on modeling, synthesis, and properties of graphene. Graphene – new trends and developments. London: Intech Open, 2015.

145.

Ghose

Working

Connell

, et al. Thermal conductivity of Ultem™/carbon nanofiller blends. High Perform Polym 2006; 18: 961–977.

146.

Ghosh

Nika

Pokatilov

, et al. Heat conduction in graphene: experimental study and theoretical interpretation. New J Phys 2009; 11: 095012.

147.

Ramesh

Itkis

, et al. Graphite nanoplatelet−epoxy composite thermal interface materials. J Phys Chem C 2007; 111: 7565–7569.

148.

Balandin

Ghosh

Bao

, et al. Superior thermal conductivity of single-layer graphene. Nano Lett 2008; 8: 902–907.

149.

Ghosh

Bao

Nika

, et al. Dimensional crossover of thermal transport in few-layer graphene. Nat Mater 2010; 9: 555–558.

150.

Miller

Kubista

Rutter

, et al. Observing the quantization of zero mass carriers in graphene. Science 2009; 324: 924–927.

151.

Novoselov

Geim

Morozov

, et al. Two-dimensional gas of massless dirac fermions in graphene. Nature 2005; 438: 197–200.

152.

Zhang

Tan

Stormer

, et al. Experimental observation of the quantum hall effect and Berry's phase in graphene. Nature 2005; 438: 201–204.

153.

Xiong

S-J

Xiong

Anderson localization of electron states in graphene in different types of disorder. Phys Rev B 2007; 76: 214204.

154.

Chang

Graphene-based nanomaterials: synthesis, properties, and optical and optoelectronic applications. Adv Funct Mater 2013; 23: 1984–1997.

155.

Shin

Kwon

Kalon

, et al. Ambipolar bistable switching effect of graphene. Appl Phys Lett 2010; 97: 262105.

156.

Baringhaus

Ruan

Edler

, et al. Exceptional ballistic transport in epitaxial graphene nanoribbons. Nature 2014; 506: 349–354.

157.

Katsnelson

Novoselov

Geim

AK.

Chiral tunnelling and the Klein paradox in graphene. Nature Phys 2006; 2: 620–625.

158.

Bolotin

KI.

Electronic transport in graphene: towards high mobility. In: Skákalová V and Kaiser AB (eds), Graphene 2014, pp. 199–227. Sawston, UK: Woodhead Publishing.

159.

Hilke

Massicotte

Whiteway

, et al. Weak localization in graphene: theory, simulations, and experiments. Scientific World J 2014; 2014: 737296.

160.

Basu

Bhattacharyya

TK.

The evolution of graphene-based electronic devices. Int J Smart Nano Mater 2010; 1: 201–223.

161.

Sharma

Singh

Gupta

, et al. Enhancing linearity in I–V characteristics by B/N doping in graphene for communication devices. J Mater Sci: Mater Electron 2017; 28: 7668–7676.

162.

Goumri

Venturini

Bakour

, et al. Tuning the luminescence and optical properties of graphene oxide and reduced graphene oxide functionnalized with PVA. Appl Phys A 2016; 122: Article 212.

163.

Badhulika

Terse-Thakoor

Villarreal

, et al. Graphene hybrids: synthesis strategies and applications in sensors and sensitized solar cells. Front Chem 2015; 3: 38.

164.

Wang

Liang

, et al. Optical, photonic and optoelectronic properties of graphene, h-BN and their hybrid materials. Nanophotonics 2017; 6: 943–976.

165.

Nair

Blake

Grigorenko

, et al. Fine structure constant defines visual transparency of graphene. Science 2008; 320: 1308.

166.

Eda

Lin

Mattevi

, et al. Blue photoluminescence from chemically derived graphene oxide. Adv Mater 2010; 22: 505–509.

167.

Xing

Zeng

, et al. Study of fluorescence quenching ability of graphene oxide with a layer of rigid and tunable silica spacer. Langmuir 2018; 34: 603–611.

168.

Mak

Shan

Heinz

TF.

Electronic structure of few-layer graphene: experimental demonstration of strong dependence on stacking sequence. Phys Rev Lett 2010; 104: 176404.

169.

Ferrari

Meyer

Scardaci

, et al. Raman spectrum of graphene and graphene layers. Phys Rev Lett 2006; 97: 187401.

170.

Zhang

Ding

Recent advances in graphene quantum dots as bioimaging probes. J Anal Test 2018; 2: 45–60.

171.

Skulason

Gaskell

Szkopek

Optical reflection and transmission properties of exfoliated graphite from a graphene monolayer to several hundred graphene layers. Nanotechnology 2010; 21: 295709.

172.

Cheng

H-M.

The fabrication, properties, and uses of graphene/polymer composites. Macromol Chem Phys 2012; 213: 1060–1077.

173.

Wang

Drzal

Qin

, et al. Mechanical properties and thermal conductivity of graphene nanoplatelet/epoxy composites. J Mater Sci 2015; 50: 1082–1093.

174.

Bhanuprakash

Parasuram

Varghese

Experimental investigation on graphene oxides coated carbon fibre/epoxy hybrid composites: mechanical and electrical properties. Compos Sci Technol 2019; 179: 134–144.

175.

Rafiee

Wang

, et al. Enhanced mechanical properties of nanocomposites at low graphene content. ACS Nano 2009; 3: 3884–3890.

176.

Shen

M-Y

Chang

T-Y

Hsieh

T-H

, et al. Mechanical properties and tensile fatigue of graphene nanoplatelets reinforced polymer nanocomposites. J Nanomater 2013; 2013: 1–9.

177.

Kumari

Kumar

Mechanical behaviour of graphene and carbon fibre reinforced epoxy based hybrid nanocomposites for orthotic callipers. J Exp Nanosci 2018; 13: S14–S23.

178.

Qin

Vautard

Drzal

, et al. Mechanical and electrical properties of carbon fiber composites with incorporation of graphene nanoplatelets at the fiber–matrix interphase. Compos B Eng 2015; 69: 335–341.

179.

Krieg

King

Jaszczak

, et al. Tensile and conductivity properties of epoxy composites containing carbon black and graphene nanoplatelets. J Compos Mater 2018; 52: 3909–3918.

180.

Chen

Zhou

, et al. Nano-structure and property transformations of carbon systems under γ-ray irradiation: a review. RSC Adv 2013; 3: 10579–10597.

181.

Liu

Chevali

, et al. A review of extending performance of epoxy resins using carbon nanomaterials. Compos B Eng 2018; 136: 197–214.

182.

Adak

Chhetri

Kim

, et al. Static and dynamic mechanical properties of graphene oxide-incorporated woven carbon fiber/epoxy composite. J Mater Eng Perform 2018; 27: 1138–1147.

183.

Bhasin

Ladani

, et al. Increasing the fatigue resistance of epoxy nanocomposites by aligning graphene nanoplatelets. Int J Fatigue 2018; 113: 88–97.

184.

Jiang

Kuila

Kim

, et al. Enhanced mechanical properties of silanized silica nanoparticle attached graphene oxide/epoxy composites. Compos Sci Technol 2013; 79: 115–125.

185.

Wan

Y-J

Gong

L-X

Tang

L-C

, et al. Mechanical properties of epoxy composites filled with silane-functionalized graphene oxide. Compos A Appl Sci Manuf 2014; 64: 79–89.

186.

King

Klimek

Miskioglu

, et al. Mechanical properties of graphene nanoplatelet/epoxy composites. J Compos Mater 2015; 49: 659–668.

187.

Tang

Jiang

Z-G

, et al. Electrically conductive rubbery epoxy/diamine-functionalized graphene nanocomposites with improved mechanical properties. Compos B Eng 2014; 67: 564–570.

188.

Yasmin

Daniel

IM.

Mechanical and thermal properties of graphite platelet/epoxy composites. Polymer 2004; 45: 8211–8219.

189.

Zakaria

Abdul Kudus

Md. Akil

, et al. Comparative study of graphene nanoparticle and multiwall carbon nanotube filled epoxy nanocomposites based on mechanical, thermal and dielectric properties. Compos B Eng 2017; 119: 57–66.

190.

Prolongo

Salom

Arribas

, et al. Influence of graphene nanoplatelets on curing and mechanical properties of graphene/epoxy nanocomposites. J Therm Anal Calorim 2016; 125: 629–636.

191.

Meng

Jin

Wang

, et al. Processable 3-nm thick graphene platelets of high electrical conductivity and their epoxy composites. Nanotechnology 2014; 25: 125707.

192.

Wan

Y-J

Tang

L-C

Yan

, et al. Improved dispersion and interface in the graphene/epoxy composites via a facile surfactant-assisted process. Compos Sci Technol 2013; 82: 60–68.

193.

Liu

Koh

, et al. Simultaneous catalyzing and reinforcing effects of imidazole-functionalized graphene in anhydride-cured epoxies. J Mater Chem 2012; 22: 18395.

194.

Nadiv

Shtein

Buzaglo

, et al. Graphene nanoribbon – polymer composites: the critical role of edge functionalization. Carbon 2016; 99: 444–450.

195.

Imran

Shivakumar

KN.

Enhancement of electrical conductivity of epoxy using graphene and determination of their thermo-mechanical properties. J Reinf Plast Compos 2018; 37: 118–133.

196.

Ramos-Galicia

Mendez

Martínez-Hernández

, et al. Improved performance of an epoxy matrix as a result of combining graphene oxide and reduced graphene. Int J Polym Sci 2013; 2013: 1–7.

197.

Chen

Jin

, et al. A design of gradient interphase reinforced by silanized graphene oxide and its effect on carbon fiber/epoxy interface. Mater Chem Phys 2014; 145: 186–196.

198.

Hsu

C-H

Hsu

M-H

Chang

K-C

, et al. Physical study of room-temperature-cured epoxy/thermally reduced graphene oxides with various contents of oxygen-containing groups. Polym Int 2014; 63: 1765–1770.

199.

Yao

Hawkins

Sue

H-J.

Preparation of epoxy nanocomposites containing well-dispersed graphene nanosheets. Compos Sci Technol 2017; 146: 161–168.

200.

Lee

M-W

Wang

T-Y

Tsai

J-L.

Mechanical properties of nanocomposites with functionalized graphene. J Compos Mater 2016; 50: 3779–3789.

201.

Kalaitzidou

Fukushima

Drzal

LT.

Multifunctional polypropylene composites produced by incorporation of exfoliated graphite nanoplatelets. Carbon 2007; 45: 1446–1452.

202.

Kim

Drzal

LT.

Comparison of exfoliated graphite nanoplatelets (xGnP) and CNTs for reinforcement of EVA nanocomposites fabricated by solution compounding method and three screw rotating systems. J Adhes Sci Technol 2009; 23: 1623–1638.

203.

Chatterjee

Nafezarefi

Tai

, et al. Size and synergy effects of nanofiller hybrids including graphene nanoplatelets and carbon nanotubes in mechanical properties of epoxy composites. Carbon 2012; 50: 5380–5386.

204.

Naebe

Wang

Amini

, et al. Mechanical property and structure of covalent functionalised graphene/epoxy nanocomposites. Sci Rep 2014; 4: 4375.

205.

Pathak

Borah

Gupta

, et al. Improved mechanical properties of carbon fiber/graphene oxide-epoxy hybrid composites. Compos Sci Technol 2016; 135: 28–38.

206.

Wang

Drzal

Qin

, et al. Effects of functionalized graphene nanoplatelets on the morphology and properties of epoxy resins. High Perform Polym 2016; 28: 525–536.

207.

Zhang

Huang

, et al. Graphite nanoplatelet modified epoxy resin for carbon fibre reinforced plastics with enhanced properties. J Nanomater 2017; 2017: 1–10.

208.

Shen

X-J

Dang

C-Y

Tang

B-L

, et al. The reinforcing effect of oriented graphene on the interlaminar shear strength of carbon fabric/epoxy composites. Mater Des 2020; 185: 108257.

209.

Feng

Xin

, et al. Fabrication of graphene-reinforced nanocomposites with improved fracture toughness in net shape for complex 3D structures via digital light processing. J Carbon Res 2019; 5: 25.

210.

Cheng

Yokozeki

, et al. Electrical conductivity and interlaminar shear strength enhancement of carbon fiber reinforced polymers through synergetic effect between graphene oxide and polyaniline. Compos A Appl Sci Manuf 2016; 90: 243–249.

211.

Han

Zhao

Sun

J-m

, et al. Effect of graphene oxide addition on the interlaminar shear property of carbon fiber-reinforced epoxy composites. New Carbon Mater 2017; 32: 48–55.

212.

Qiao

Wang

, et al. Comparison of rigid and flexible structural daimines grafted carbon fiber for enhancing the interfacial and mechanical properties of carbon fiber/epoxy composites. Compos Interfaces 2019; 26: 905–920.

213.

Chen

Jin

, et al. Role of a gradient interface layer in interfacial enhancement of carbon fiber/epoxy hierarchical composites. J Mater Sci 2015; 50: 112–121.

214.

Song

Wang

, et al. Interfacially reinforced carbon fiber/epoxy composite laminates via in-situ synthesized graphitic carbon nitride (g-C₃N₄). Compos B Eng 2019; 158: 259–268.

215.

Jang

H-K

Kim

H-I

Dodge

, et al. Interfacial shear strength of reduced graphene oxide polymer composites. Carbon 2014; 77: 390–397.

216.

Lee

M-W

Wang

T-Y

Tsai

J-L.

Characterizing the interfacial shear strength of graphite/epoxy composites containing functionalized graphene. Compos B Eng 2016; 98: 308–313.

217.

Beggs

Servinis

Gengenbach

, et al. A systematic study of carbon fibre surface grafting via in situ diazonium generation for improved interfacial shear strength in epoxy matrix composites. Compos Sci Technol 2015; 118: 31–38.

218.

Yuan

Zhu

Cai

, et al. Influence of different surface treatments on the interfacial adhesion of graphene oxide/carbon fiber/epoxy composites. Appl Surf Sci 2018; 458: 996–1005.

219.

Shrivastava

Singh

KK.

Interlaminar fracture toughness characterization of laminated composites: a review. Polym Rev 2020; 60: 542–593.

220.

Fenner

Daniel

IM.

Hybrid nanoreinforced carbon/epoxy composites for enhanced damage tolerance and fatigue life. Compos A Appl Sci Manuf 2014; 65: 47–56.

221.

Shadlou

Alishahi

Ayatollahi

MR.

Fracture behavior of epoxy nanocomposites reinforced with different carbon nano-reinforcements. Compos Struct 2013; 95: 577–581.

222.

Bhasin

Raj

, et al. Improvements to the mode I fatigue resistance of epoxy nanocomposites using aligned graphene nanoplatelets. In: 21st international conference on composite materials, Xi'an, China, 20–25 April 2017.

223.

Galpaya

Wang

George

, et al. Preparation of graphene oxide/epoxy nanocomposites with significantly improved mechanical properties. J Appl Phys 2014; 116: 053518.

224.

Shokrieh

Ghoreishi

Esmkhani

, et al. Effects of graphene nanoplatelets and graphene nanosheets on fracture toughness of epoxy nanocomposites. Fatigue Fract Eng Mater Struct 2014; 37: 1116–1123.

225.

Deng

Influence of fiber-matrix adhesion on mechanical properties of graphite/epoxy composites: II. Interlaminar fracture and inplane shear behavior. J Reinf Plast Compos 1999; 18: 1041–1057.

226.

Ladani

Zhang

, et al. Aligning multilayer graphene flakes with an external electric field to improve multifunctional properties of epoxy nanocomposites. Carbon 2015; 94: 607–618.

227.

Liu

Sun

Wang

, et al. Planar porous graphene woven fabric/epoxy composites with exceptional electrical, mechanical properties, and fracture toughness. ACS Appl Mater Interfaces 2015; 7: 21455–21464.

228.

Domun

Hadavinia

Zhang

, et al. Improving the fracture toughness properties of epoxy using graphene nanoplatelets at low filler content. Nanocomposites 2017; 3: 85–96.

229.

Jia

Feng

Zou

An investigation on mode II fracture toughness enhancement of epoxy adhesive using graphene nanoplatelets. Compos B Eng 2018; 155: 452–456.

230.

Wang

Yang

Pei

, et al. Some aspects of thermal transport across the interface between graphene and epoxy in nanocomposites. ACS Appl Mater Interfaces 2016; 8: 8272–8279.

231.

Atif

Shyha

Inam

Mechanical, thermal, and electrical properties of graphene-epoxy nanocomposites – a review. Polymers (Basel) 2016; 8: 281.

232.

Bustero

Gaztelumendi

Obieta

, et al. Free-standing graphene films embedded in epoxy resin with enhanced thermal properties. Adv Compos Hybrid Mater 2020; 3: 31–40.

233.

Zhang

Liu

, et al. Synergistic effects of spray-coated hybrid carbon nanoparticles for enhanced electrical and thermal surface conductivity of CFRP laminates. Compos. A Appl Sci Manuf 2018; 105: 9–18.

234.

Shen

Wang

, et al. Effect of functionalization on thermal conductivities of graphene/epoxy composites. Carbon 2016; 108: 412–422.

235.

Shahil

Balandin

AA.

Graphene-multilayer graphene nanocomposites as highly efficient thermal interface materials. Nano Lett 2012; 12: 861–867.

236.

Wang

, et al. Thermal conductivity improvement of epoxy composite filled with expanded graphite. Ceramics Int 2015; 41: 13541–13546.

237.

Luo

Guo

, et al. Simultaneous reduction and surface functionalization of graphene oxide for enhancing flame retardancy and thermal conductivity of mesogenic epoxy composites. Polym Int 2017; 66: 98–107.

238.

Teng

C-C

C-CM

C-H

, et al. Thermal conductivity and structure of non-covalent functionalized graphene/epoxy composites. Carbon 2011; 49: 5107–5116.

239.

Zhou

Koga

Nogi

, et al. Targeted kinetic strategy for improving the thermal conductivity of epoxy composite containing percolating multi-layer graphene oxide chains. Express Polym Lett 2015; 9: 608–623.

240.

Wang

Dai

, et al. Enhanced thermal and electrical properties of epoxy composites reinforced with graphene nanoplatelets. Polym Compos 2015; 36: 556–565.

241.

Min

Cao

, et al. A graphite nanoplatelet/epoxy composite with high dielectric constant and high thermal conductivity. Carbon 2013; 55: 116–125.

242.

Tien

Park

Han

, et al. Electrical and thermal conductivities of stycast 1266 epoxy/graphite composites. J Korean Phy Soc 2011; 59: 2760–2764.

243.

Wang

Yan

and Ma L. Graphene nanocomposites. In: Hu N (ed) Composites and their properties. London: Intech Open, 2012, pp. 17–36.

244.

Stankovich

Dikin

Dommett

, et al. Graphene-based composite materials. Nature 2006; 442: 282–286.

245.

Han

, et al. High-efficiency enhancement on thermal and electrical properties of epoxy nanocomposites with core-shell carbon foam template-coated graphene. Compos A Appl Sci Manuf 2019; 120: 95–105.

246.

Fan

Zheng

Wei

, et al. Effect of carbon black on electrical property of graphite nanoplatelets/epoxy resin composites. Polym Eng Sci 2009; 49: 2041–2045.

247.

Jiang

Sun

Zhang

H-B

, et al. Graphene-coated ZnO tetrapod whiskers for thermally and electrically conductive epoxy composites. Compos A Appl Sci Manuf 2017; 94: 104–112.

248.

Ghosal

Sarkar

Biomedical applications of graphene nanomaterials and beyond. ACS Biomater Sci Eng 2018; 4: 2653–2703.

249.

Zheng

Wong

S-C.

Electrical and mechanical properties of expanded graphite-reinforced high-density polyethylene. J Appl Polym Sci 2004; 91: 2781–2788.

250.

Elmarakbi

Azoti

Martorana

, et al. Graphene-based composite materials for automotives. In: 20th international conference on composite materials, Copenhagen, 19–24 July 2015.

251.

Valorosi

De Meo

Blanco-Varela

, et al. Graphene and related materials in hierarchical fiber composites: production techniques and key industrial benefits. Compos Sci Technol 2020; 185: 107848.

252.

Wen

, et al. Semiconducting graphene: converting graphene from semimetal to semiconductor. Nanoscale 2013; 5: 1353–1368.

253.

Huang

Liang

Chen

An overview of the applications of graphene-based materials in supercapacitors. Small 2012; 8: 1805–1834.

254.

Ponnamma

Sadasivuni

KK.

Graphene/polymer nanocomposites: role in electronics. In: Sadasivuni KK, Ponnamma D, Kim J and Sabu Th (eds), Graphene-based polymer nanocomposites in electronics. Berlin: Springer, 2015, pp.1–24.

255.

Obradovic

Kotlyar

Heinz

, et al. Analysis of graphene nanoribbons as a channel material for field-effect transistors. Appl Phys Lett 2006; 88: 142102.

256.

Liu

Huang

, et al. Organic photovoltaic devices based on a novel acceptor material: graphene. Adv Mater 2008; 20: 3924–3930.

257.

Lin

Yeh

, et al. High mobility flexible graphene field-effect transistors with self-healing gate dielectrics. ACS Nano 2012; 6: 4469–4474.

258.

Zheng

Wang

Quhe

, et al. Sub-10 nm gate length graphene transistors: operating at terahertz frequencies with current saturation. Sci Rep 2013; 3: 1314.

259.

Mahmoudi

Wang

Hahn

Y-B.

Graphene and its derivatives for solar cells application. Nano Energy 2018; 47: 51–65.

260.

Algamili

Khir

MHM

Dennis

, et al. A review of actuation and sensing mechanisms in MEMS-based sensor devices. Nanoscale Res Lett 2021; 16: 16.

261.

Jin

Feng

Ponnamma

, et al. Review on exploration of graphene in the design and engineering of smart sensors, actuators and soft robotics. Chem Eng J Adv 2020; 4: 100034.

262.

Wang

Jiao

Tung

, et al. Photoresponsive graphene composite bilayer actuator for soft robots. ACS Appl Mater Interfaces 2019; 11: 30290–30299.

263.

Pumera

Graphene-based nanomaterials for energy storage. Energy Environ Sci 2011; 4: 668–674.

264.

Asenbauer

Eisenmann

Kuenzel

, et al. The success story of graphite as a lithium-ion anode material – fundamentals, remaining challenges, and recent developments including silicon (oxide) composites. Sustainable Energy Fuels 2020; 4: 5387–5416.

265.

Singh

Meyyappan

Nalwa

HS.

Flexible graphene-based wearable gas and chemical sensors. ACS Appl Mater Interfaces 2017; 9: 34544–34586.

266.

Khan

Ali

Bermak

Recent developments in printing flexible and wearable sensing electronics for healthcare applications. Sensors (Basel) 2019; 19: 1230.

267.

Boroujerdi

Abdelkader

Paul

State of the art in alcohol sensing with 2D materials. Nano-Micro Lett 2020; 12: 33.

268.

Krishnan

Tadiboyina

Chavali

, et al. Graphene-based polymer nanocomposites for sensor applications. In: Pal K (ed) Hybrid nanocomposites. Singapore: Pan Stanford Publishing, 2019, pp.1–62.

269.

Liu

Tao

Yang

, et al. Synthesis, characterization, and multilayer assembly of pH sensitive graphene−polymer nanocomposites. Langmuir 2010; 26: 10068–10075.

270.

Das

Prusty

Graphene-based polymer composites and their applications. Polym Plast Technol Eng 2013; 52: 319–331.

271.

Lyu

Richardson

, et al. Flexible neural electrode array based-on porous graphene for cortical microstimulation and sensing. Sci Rep 2016; 6: 33526.

272.

Wang

Electrochemical glucose biosensors. Chem Rev 2008; 108: 814–825.

273.

Sayyar

Murray

Thompson

, et al. Covalently linked biocompatible graphene/polycaprolactone composites for tissue engineering. Carbon 2013; 52: 296–304.

274.

Sarkar

Madras

Chatterjee

Dendron conjugation to graphene oxide using click chemistry for efficient gene delivery. RSC Adv 2015; 5: 50196–50211.

275.

Eskiizmir

Baskın

Yapıcı

Graphene-based nanomaterials in cancer treatment and diagnosis. In: Grumezescu

(ed.) Fullerens, graphenes and nanotubes. Norwich, NY: William Andrew Publishing, 2018, pp.331–374.

276.

Sheng

Tang

Peng

, et al. Graphene oxide based fluorescent nanocomposites for cellular imaging. J Mater Chem B 2013; 1: 512–521.

277.

Kireev

Offenhäusser

Graphene & two-dimensional devices for bioelectronics and neuroprosthetics. 2D Mater 2018; 5: 042004.

278.

Pei

Travas-Sejdic

Williams

DE.

Reversible electrochemical switching of polymer brushes grafted onto conducting polymer films. Langmuir 2012; 28: 8072–8083.

279.

Aboutalebi

Jalili

Esrafilzadeh

, et al. High-performance multifunctional graphene yarns: toward wearable All-carbon energy storage textiles. ACS Nano 2014; 8: 2456–2466.

280.

Nine

Cole

Tran

DNH

, et al. Graphene: a multipurpose material for protective coatings. J Mater Chem A 2015; 3: 12580–12602.

281.

Afroj

Tan

Abdelkader

, et al. Highly conductive, scalable, and machine washable graphene‐based E‐textiles for multifunctional wearable electronic applications. Adv Funct Mater 2020; 30: 2000293.

282.

Gao

Song

Zhang

, et al. Cotton-textile-enabled, flexible lithium-ion batteries with enhanced capacity and extended lifespan. Nano Lett 2015; 15: 8194–8203.

283.

Mao

Zhang

Highly conductive graphene-coated silk fabricated via a repeated coating-reduction approach. J Mater Chem C 2015; 3: 4265–4268.

284.

Shateri-Khalilabad

Yazdanshenas

ME.

Fabricating electroconductive cotton textiles using graphene. Carbohydr Polym 2013; 96: 190–195.

285.

Tang

Tian

, et al. Functionalization of cotton fabric with graphene oxide nanosheet and polyaniline for conductive and UV blocking properties. Synthetic Metals 2015; 202: 82–88.

Graphene nanocomposites: A review on processes,properties,and applications

Abstract

Keywords

Introduction

Synthesis of graphene

Mechanical exfoliation

Liquid-phase exfoliation

Chemical vapor deposition (CVD)

Epitaxial growth

Fabrication of graphene nanocomposites

Solution mixing technique

In-situ polymerization

Melt blending

Electrospinning

Fabrication process of fiber-based graphene nanocomposites

Resin transfer molding and vacuum-assisted resin transfer molding

Nanostitching

Properties of graphene

Physical

Mechanical

Thermal

Electrical

Optical

Properties of graphene nanocomposites

Mechanical properties

Tensile

Flexural

Interlaminar shear strength (ILSS)

Interfacial shear strength (IFSS)

Interlaminar fracture toughness

Mode-I fracture toughness (GIC)

Mode-II fracture toughness (GIIC)

Thermal conductivity

Electrical conductivity

Application areas of graphene and graphene nanocomposites

Industrial structural components

Electronics

Energy storage

Sensors

Biomedical

Textile industries

Conclusion

Footnotes

Declaration of conflicting interests

Funding

ORCID iDs

References

Mode-I fracture toughness (G_IC)

Mode-II fracture toughness (G_IIC)