Graphene Nanoplatelets Fillers Research Articles

Flexible carbon‐based fluoropolymer composites for effective EMI shielding and heat dissipation

AbstractContemporary applications require protection against overheating and electromagnetic radiation interference, preferably with reduced mass and enhanced basic performance, such as flammability or chemical or UV resistance and often also low or non‐electrically conductive. Materials exhibiting all these functions can be designed, but there is usually not just one but several different materials with advanced processing requirements; therefore, a simple manufacturing method providing percolation path formation involving powder mixing and hot pressing of providing excellent flexibility terpolymer comprising tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride monomeric units (THV)‐based nanocomposites is presented here. The addition of the graphene nanoplatelets (GNPs) and multiwalled carbon nanotubes (MWCNTs) significantly improves the EMI shielding effectiveness, up to SETOT = 23 dB for the GNP filler, SETOT = 17 dB for the MWCNT/GNP filler per 1 mm samples thickness and enhances almost 900% the thermal conductivity to almost 2 W/mK per GNP filler. Besides this improvement, the electrical conductivity remains at a low level, not surpassing 1.5 S/cm, which is, as mentioned above, beneficial in many applications, especially thermal management. Moreover, the proposed material is an excellent alternative to flexible foam or sponges.Highlights Structural, electrical, EMI shielding, and thermal properties of flexible THV/GNP, THV/MWCNT, and THV/MWCNT/GNP nanocomposites are shown here. The oriented, long as over 1 mm filler paths are observed. The GNP filler provides the best thermal conductivity enhancement of over 800% compared to bare polymer. The EMI shielding effectiveness is dominated by absorption for all THV‐based nanocomposites. The electrical conductivity follows the power law, reaching σ = 1.49 S/cm for GNP‐filled nanocomposites.

Hybrid network formation of silicon carbide and expanded graphene nanoplatelets in epoxy resin for thermal management

AbstractThe current study discusses the incorporation of silicon carbide (SiC) and expanded graphene nanoplatelets (GNP) hybrid filler into epoxy resin to enhance its thermal conductivity, mechanical, and electrical insulation properties. The hybrid filler was incorporated into the epoxy resin by ultrasonic‐assisted blending solution process, and the thermal, electrical, and mechanical properties of the samples were assessed. The results displayed that both SiC and GNP fillers enhance the thermal conductivity of the epoxy resin. Addition of 15.3 wt% SiC/GNP filler (15/0.3) to pure epoxy increased the thermal conductivity coefficient by over 230%. The samples maintained the electrical insulation properties with electrical conductivity (EC) less than 10−9 S/m. Both fillers reduced the breakdown voltage of the samples. Furthermore, strong filler‐matrix adhesion resulted in a significant 414% improvement in Izod impact strength.Highlights Combining SiC and GNP fillers affects the thermal and electrical properties of epoxy. SiC and GNP synergistically improved the thermal diffusivity and conductivity of epoxy. The prepared composites remained in the range of electrical insulation. The impact strength of composites enhanced more than 400% compared to epoxy.

Study of thermal and mechanical behavior by analyzing reinforcement effect of graphene nanoplatelets on polyamide-66 composite system developed via melt-mixing technique

In the present study, graphene nanoplatelets (GNP) reinforced polyamide 6,6 (PA-66) composite was studied to investigate the thermal and mechanical properties of PA-66/GNP composite. The composites were developed by varying wt% (1, 3, 5, and 10 wt%) of GNP loading using a co-rotating, intermeshing, twin-screw extruder via melt-mixing and injection molding process. In order to understand the thermal and mechanical behavior of PA-66/GNP composite, various thermal (TGA and DSC) and mechanical (tensile, impact, and flexural) tests were carried out. The FTIR spectral analysis was done to identify the presence of different functional groups in the PA-66/GNP composite, indicating the strong enough Vander-Waals interaction between the PA-66 matrix and GNP filler contents. The TGA result shows a significant enhancement in the thermal stability of the composite by increasing wt% of GNP. The DSC analysis exhibits a significant reduction in enthalpy of fusion (∆Hm) and a decrease in the degree of crystallinity with increasing wt% of GNP, reflecting a depressed form of α-crystalline structure. Further, the significant growth in tensile modulus and tensile strength were identified under the mechanical performance of the PA-66/GNP composite. An increasing trend in tensile modulus and tensile strength characteristics was observed, and tensile modulus exhibited an enhancement of ∼96% than pure PA-66 at 10 wt% of GNP. Also, the tensile strength is found to be ∼16% higher than that of pure PA-66 matrix. Similarly, the impact test result shows a decreasing trend in impact strength on increasing wt% of GNP reinforcements, indicating the restriction to the molecular mobility due to improved brittle behavior. Further, the flexural modulus is found to be increased by ∼28% at 10 wt%, and the flexural strength is found to have an enhancement of ∼9% at 3 wt% than pure PA-66 polymer matrix of GNP loadings, respectively. The influence of GNP filler content reinforced PA-66 composite on the thermal and mechanical properties is found to be noteworthy.

Sunflower oil-based polyurethane/graphene composite: Synthesis and properties

Polyurethane/graphene composites have attracted significant attention featuring their wide applications in automotive interiors, coatings, and leather parts to bioengineering. This research focuses on the facile synthesis of biobased polyurethane (PU) by employing sunflower oil as a renewable resource. The synthesized biobased PU was reinforced with graphene nanoplatelets (GNP) and graphene nanoribbons (GNR) to fabricate composite films by solution-casting technique. By changing the filler content (0.01-0.05 wt%), a series of composite films were prepared. The addition of graphene derivatives to the PU matrix improved the mechanical, thermal, and surface properties of the composites compared to the pristine PU film. The incorporation of GNR and GNP fillers enhanced the storage modulus of polymeric film, as for neat PU, was noted maximum at 892 MPa which increased and noticed a maximum of 1121 MPa and 1487 MPa for 0.02 wt % GNP/PU and GNR/PU composite films, respectively. The tensile strength was obtained at 35 MPa and 14 MPa for 0.02 wt % GNP/PU and 0.01 wt % GNR/PU, as compared to 9.45 MPa for the pure PU film. The morphological studies by atomic force microscopy showed a good distribution of GNR and GNP fillers within the polyurethane matrix. The GNP/PU and GNR/PU composite films displayed excellent chemical resistance to different solvents. This work put forward a great utilization of renewable sunflower oil and graphene derivatives to fabricate PU composites with improved properties for potential applications.

Enhanced temperature-responsive functions of thermal metamaterials by interface engineering

A phase-change thermal metamaterial (PCTM) has attracted a lot of attention to implement responsive thermal functions that can be adaptable to ambient environments. Temperature responsive PCTMs consisting of aligned metal backbones and phase change materials (PCMs) are capable of transforming artificial heat paths enabled by rapidly transiting thermophysical characteristics at certain temperatures. However, fabricating the PCTMs essentially involves the interfacial boundaries of different materials such as metal and PCMs, thereby degrading thermal transport between them. Moreover, while the phase of the material is altered from solid to liquid or vice versa, the instability of the interfaces inevitably occurs. Herein, we report an interface engineering of PCTMs using layer-by-layer (LbL) coating layers and nanocomposite PCMs to improve the on/off switching transition of thermal functions manipulating the heat flux in response to a specific temperature. LbL-assembled ultra-thin interfaces (multi-walled carbon nanotube (MWCNT)-polyethylenimine (PEI) layers and MWCNT-PEI-Silane layers) as interfacial thermal resistance compensators and PCM nanocomposites using graphene nanoplatelets (GNPs) are incorporated into thermal shifters based on stainless steel backbones. The LbL interfaces reduce the physical voids and phonon scattering between PCMs and metal surfaces while the GNP fillers increase the thermal conductivity of the PCMs in solid phases. The engineered PCTMs highly amplify the on/off switching ratio of thermal shifter unit cells and enhance overall thermal functions of temperature responsive TM modules (shield, concentrator, diffuser, and inverter). This work can pave a way for feasible solutions of interfacial resistances and instability in TMs.

Bio-based acrylated epoxidized jatropha oil incorporated with graphene nanoplatelets in the assessment of corrosion resistance coating

Vegetable oil has been extensively investigated as a precursor to the eco-friendly coating as an alternative to petrochemical-based resources due to its lower carbon footprint properties. In view of this, jatropha oil (JO), a type of non-edible oil, has received significant attention in this field. The present study was undertaken to utilize acrylated epoxidized jatropha oil (AEJO) resin and to evaluate the anti-corrosion performance with the addition of graphene nanoplatelets (GNP). AEJO-GNP nanocomposites coatings were obtained after three passes of ultraviolet (UV) irradiation. The corrosion protection of all nanocomposites coatings was investigated by electrochemical measurements. The results showed that the corrosion performance of AEJO-GNP nanocomposites coatings improved from the blank coating. Among all coatings tested, AEJO-0.5 wt% GNP exhibited the strongest barrier property and maximum performance in corrosion protection. The result was supported by water contact angle and pull-off adhesion tests. In addition, the highest pull-off adhesion strength for GNP fillers added coatings was established at 0.5 wt% of GNP. High hydrophobicity and pull-off adhesion strength coatings provided a physical barrier that created a tortuosity pathway for corrosive electrolytes to reach the metal surface and thus showed better anti-corrosion resistance. Thus, nanocomposites coatings with 0.5 wt% GNP exhibited the best anti-corrosive efficacy and surface coating property.

Comparative Study on the Effect of Aluminium Trihydrate and Carbon Nanofillers on Thermal Properties of Glass Fiber Reinforced Epoxy Composites

High performance glass fiber reinforced epoxy composites are in greater demand in several industrial applications, from civil structures to aviation industry. The epoxy has highly cross-linked structure and is found to be high performance polymer. Further, carbon nanofillers such as multi-walled carbon nanotubes (MWCNT), graphene nanoplatelets (GNP) and thermally stable microfiller aluminium trihydrate (ATH) are being used to improve the thermal properties. GNP and MWCNT posses high aspect ratio and specific surface area contributing to improvement in thermal properties of composites. In spite of this, there are difficulties connected with nanofiller addition, such as dispersion and interaction. The fabricated nanocomposites are based on ECR glass fiber and epoxy resin by adding GNP, MWCNT and ATH fillers using pultrusion process assisted by ultrasonication. For the purpose of comparison, composites containing only MWCNT, GNP and ATH were also tested. The XRD and SEM were used to study the fillers dispersion and interaction. The thermogravemetric analysis(TGA) was carried out to determine the thermal stability of composites. From the thermal analysis result, it is found that the epoxy-MWCNT-GNP-ATH composite has enhanced thermal stability due to the addition of ATH micro filler.

Effect of the Particle Size and Layer Thickness of GNP Fillers on the Dielectric Properties and Actuated Strain of GNP-PDMS Composites.

Dielectric elastomer actuators (DEAs), a type of electroactive polymers (EAPs), are smart materials that are used in various fields such as artificial muscles and biomimetic robots. In this study, graphene nanoplatelets (GNPs), which are conductive carbon fillers, were added to a widely used DEA, namely, polydimethylsiloxane (PDMS), to improve its low actuated strain. Four grades of GNPs were used: H5, H25, M5, and M25 (here, the number following the letter indicates the average particle size of the GNPs in μm). The average layer thickness of the H grade is 13–14 nm and that of the M grade is 5–7 nm. PDMS composites were prepared by adding 0.5, 1, 2, and 3 wt% of each GNP, following which the mechanical properties, dielectric properties, and actuated strain of the composites were measured. The mechanical properties were found to increase as the particle size increased. Regarding the dielectric characteristics, it was found that the higher the aspect ratio of the filler, the easier the formation of a micro-capacitor network in the composite—this led to an increase in the dielectric constant. In addition, the higher amounts of GNPs in the composites also led to an increase in the dielectric constant. For the actuated strain analysis, the electromechanical sensitivity was calculated using the ratio of the dielectric constant to the Young’s modulus, which is proportional to the strain. However, it was found that when the loss tangent was high, the performance of the actuated strain decreased owing to the conversion of electric energy into thermal energy and leakage current loss. As a result, the highest actuated strain was exhibited by the M25 composite, with an actuated strain value of 3.01% measured at a low electric field (<4 kV/mm). In conclusion, we proved that the GNP–PDMS composites with a thin layer and large particle size exhibited high deformation.

Flexible and shape-configurable PI composite aerogel films with tunable dielectric properties

In the past decade, the development of polyimide (PI) aerogel films has drawn a great attention due to their enhanced physical and mechanical performance compared to conventional bulk monolithic aerogels. However, their ultralow dielectric constant has limited their application in energy-related fields mainly energy storage and energy harvesting. Therefore, it is of great interest to improve and tailor the dielectric properties of PI aerogel films. This work presents the fabrication of novel PI composite aerogel films with tunable dielectric properties based on sol-gel approach combined with graphene nanoplatelet fillers. The structural analysis of aerogels indicated the addition of graphene resulted in altering the aerogel nanostructure by improving the homogeneity and uniformity of composite gel films. When the mechanical properties were evaluated, aerogels displayed excellent flexibility, improved mechanical properties, and outstanding machinability. This was accompanied by significant improvement in thermal stability of aerogels. Eventually, inclusion of graphene nanoplatelet was identified as an effective strategy for tailoring dielectric properties of aerogels and this was attributed to enhancement of interfacial polarization's density.

Graphene nanoplatelets based polyimide/Pebax dual-layer mixed matrix hollow fiber membranes for CO2/CH4 and He/N2 separations

Mixed matrix membranes are key in the preparation of stable, stretchy, durable and efficient membranes for gas separation applications. To this aim, the perfect filler nanomaterials’ dispersion is needed. At the same time the replacement of toxic solvents with green ones is also a priority in science, including the membrane technology. Herein, we present the development steps, their structural characteristics and the gas selectivity properties of graphene nanoplatelets (GNPs) based mixed matrix hollow fiber (HF) membranes. In specific, dual-layer composite polymeric hollow fiber membranes, for CO2/CH4 and He/N2 gas separations, were prepared by directly dip-coating a single selective layer on prepared porous HF supports without the use of any gutter layer. Asymmetric BTDA-TDI/MDI (P84) co-polyimide-based HFs that acted as porous supports, were fabricated via the dry-wet phase inversion process and the commercial poly(ether-block-amide) Pebax-1657 was chosen as a high CO2-selective separation layer material, dip-coated on the HF supports. The positive influence of the incorporation of GNPs as promising nanofiller in both, the polymeric matrix (support) and the selective layer, in parallel with the partial replacement of toxic NMP by GBL -a "green" solvent- in the support's spinning process, were all evaluated and confirmed. CO2/CH4 and He/N2 selectivities up to 82 and 20, respectively with CO2 and He permeances of 3 and 2.7 GPU, respectively were measured under real binary gas mixture conditions at 1.3 bar(a) transmembrane pressure at 298 K for dual-layer composite, with GNPs filler, HF (DL-HF) membranes.

Effect of Graphene Nanoplatelets on Water Absorption Properties of Coconut Shell Reinforced Unsaturated Polyester Composites

Coconut shell (CS) reinforced unsaturated polyester (UPE) composites have been prepared by using hand lay-up and compression molding techniques. To improve fiber-matrix adhesion, the CS was chemically treated by two chemical treatments, which are alkali (NaOH) and alkali-silane with concentration NaOH (6%) and silane (2%). To enhance the performance of CS-UPE composites, graphene nano platelets (GNP) was also added as nanofiller. The water absorption tests were conducted to characterize the physical properties of the composites. The result shows that water absorption increases with the increasing GNP. The more adding of GNP fillers’ weight percentages, the higher the water absorption will be getting.

Graphene nanoplatelet reinforcement for thermal and mechanical properties enhancement of bio-based polyamide 6, 10 nanocomposites for automotive applications

In this study, graphene nanoplatelets (GNP) (2%, 4%, 6% and 8% by wt.) were incorporated into PA610 matrix via melt compounding using a twin-screw extruder to compensate for the relatively lower mechanical and thermal properties of bio-based PA610 compared to petroleum-based polyamide. Thermogravimetric analysis showed a slight improvement in thermal stability which peaked for the formulation of 6% GNP. Shear-thinning behavior was more severe with the increase in GNP content. Significant improvement in tensile modulus was observed with increment up to 95% for composites with 8% GNP loading. Flexural modulus increased by16% and strength by 9.5% for 8% GNP composites. These results suggest GNP fillers can be used to enhance the mechanical and thermal properties of PA610 for automotive applications.

The Reinforcing Effect of Graphene on the Mechanical Properties of Carbon-Epoxy Composites

Graphene nanoplatelets (GNPs) are novel nanofillers holding attractive characteristics, including vigorous compatibility with majority polymers, outstanding mechanical, thermal, and electrical properties. In this study, the outstanding GNPs filler was reinforced to the epoxy matrix and carbon fabric/epoxy hybrid composite slabs to enrich their mechanical properties. Graphene nanoplatelets of 0.5, 1, 1.5 and 2 weight percentages were integrated into the epoxy and the physico-mechanical (microstructure, density, tensile, flexural and impact strength) properties were investigated. Furthermore, the mechanical properties of unfilled and 1 wt% GNPs filled carbon fabric/epoxy hybrid composite slabs were investigated. Subsequently, noteworthy improvement in the mechanical properties was conquered for the carbon fabric/epoxy hybrid composites.

Thermal and Mechanical Behavior of Wood Plastic Composites by Addition of Graphene Nanoplatelets.

Wood plastic composites (WPCs) incorporating graphene nano-platelets (GNPs) were fabricated using hot-pressed technology to enhance thermal and mechanical behavior. The influences of thermal filler content and temperature on the thermal performance of the modified WPCs were investigated. The results showed that the thermal conductivity of the composites increased significantly with the increase of GNPs fillers, but decreased with the increase of temperature. Moreover, thermogravimetric analysis demonstrated that coupling GNPs resulted in better thermal stability of the WPCs. The limiting oxygen index test also showed that addition of GNPs caused good fire retardancy in WPCs. Incorporation of GNPs also led to an improvement in mechanical properties as compared to neat WPCs. Through a series of mechanical performance tests, it could be concluded that the flexural and tensile moduli of WPCs were improved with the increase of the content of fillers.

Polyethylene/Graphene Nanoplatelet Nanocomposite-Based Insulating Materials for Effective Reduction of Space Charge Accumulation in High-Voltage Direct-Current Cables

We have demonstrated a straightforward hydrophobic surface modification of graphene nanoplatelets (GNPs) through a defect-healing process to fabricate well-dispersed insulating low-density polyethylene (LDPE)/GNP nanocomposites and have confirmed their effective suppression of space charge accumulation. Without any organic modifiers, GNPs containing oxygen-based functional groups at the edges were successfully reduced at optimal high-temperature defect-healing condition and modified to have hydrophobic surface properties similar to those of the LDPE matrix. The degree of dispersion and the reproducibility of the mechanically melt-mixed LDPE/GNP nanocomposites were immediately analyzed by thickness-normalized optical absorption measurement. In the LDPE matrix, below the percolation threshold concentration, well-dispersed GNP fillers effectively acted as trapping sites under high electric fields, resulting in the successful suppression of packet-like space charge accumulation (field enhancement factor=1.04 @ 0.1 wt% LDPE/GNP nanocomposite).

Preparation and characterization of poly (lactic acid) (PLA)/polyamide 6 (PA6)/graphene nanoplatelet (GNP) blends bio-based nanocomposites

Biodegradable PLA is commonly derived from renewable resources and benign to the environment. It is a brittle thermoplastic with high strength and modulus; thus a suitable candidate for replacing conventional petroleum-based plastic. However, due to its limitation, PLA needs to be blended with other polymers and fillers for properties modifications. The aim of this work was to prepare PLA/PA6/GNP nanocomposites and characterize on the mechanical, thermal, chemical and dispersion of nanofiller in binary blend systems. PLA/PA6/GNP nanocomposites were blended by using a Haake twin screw extruder via melt intercalation method. The ratio of the polymer matrix was fixed at 20:80 and the processing temperature was in the range of 205 °C to 260 °C. Graphene nanoplatelet fillers were then loaded in the PLA/PA6 blends with 0.5, 1.0, 3.0 and 5.0 wt%. It was found that PLA/PA6/GNP (5.0) nanocomposites were the overall highest in terms of thermal and mechanical properties. PLA/PA6/GNP nanocomposites improved the mechanical properties in terms of elongation at break and maximum stress as well as improved the degradation temperature. The property improvement in the nanocomposites was due to the dispersion of GNP in the polymer matrix. It was also found that there was no chemical interaction between a functional group of nanocomposites. It can be concluded that nanocomposites were incompatible and immiscible with PA6.

The effect of graphene nanoplatelet thickness on the fracture toughness of Si3N4 composites

Si3N4 composites with 3 and 5 wt% of graphene nanoplatelet (GNP) additions were prepared by spark plasma sintering. We used both commercially available GNPs and thinner few-layer graphene nanoplatelets (FL-GNPs) prepared by further exfoliation through ball milling with melamine addition. We found that by employing thinner FL-GNPs as filler material a 100% increase in the fracture toughness of Si3N4/3 wt% FL-GNP composites (10.5 ± 0.2 MPa m1/2) can be achieved as compared to the monolithic Si3N4 samples (5.1 ± 0.3 MPa m1/2), and 60% increase compared to conventional Si3N4/3 wt% GNP composites (6.6 ± 0.4 MPa m1/2). For 5 wt% filler content the increase of the fracture toughness was near 50% for both GNP and FL-GNP fillers. The hardness of the composites decreased with increasing GNP content. However, composites reinforced with 5 wt% of FL-GNPs displayed 30% higher Vickers hardness (12.8 ± 0.2 GPa) than their counterparts comprising conventional GNP fillers (9.8 ± 0.2 GPa). We attribute the enhanced mechanical properties obtained with thinner FL-GNPs to their higher aspect ratio leading to a more homogeneous dispersion, higher interface area, as well as smaller pores in the ceramic matrix.

Reinforcement effect of nanocomposites with single/hybrid graphene nanoplatelets and magnesium hydroxide

Polypropylene matrix composites based on single filler of graphene nanoplatelets (GNP) and hybrid fillers of GNP/magnesium hydroxide (MH) were fabricated via melt blending process using internal mixer followed by compression moulding. Different concentration ranges of GNP (0.5–2 mass%) and MH (5–15 mass%) in the composites were used. Upon inclusion of MH particle, the thermal stability of the composites was further improved after an initial enhancement by GNP filler. The highly flame-resistant composites were obtained that a notable decrease in burning rate was achieved with increasing GNP concentrations relative to neat PP, and the addition of MH led to further deficiency of the reduction in burning rate. The improvement in thermal stability and flame retardancy properties was strongly correlated with the formation of charred yield by adding filler. Tensile measurements indicated that the most noteworthy improvement in tensile strength and Young’s modulus was observed for 1 mass% GNP and 5 mass% MH. It can be concluded that the GNP and MH served as effective hybrid reinforcing fillers to attain the optimal thermo-mechanical characteristics.

The Using of Graphene Nano‐Platelets for a Better through‐Plane Thermal Conductivity for Polypropylene

In‐plane alignment of graphene nanoplatelets (GNPs) in thin thermal interface material layers suppresses the through‐plane heat transport, which limits the performance of materials. In order to suppress the in‐plane alignment of the GNP filler within polypropylene (PP) and increase the through‐plane component, modification of GNP (MG) was performed in this study. For this aim, GNP was treated with diallyldimethylammonium chloride solution and filled with PP at different weight fractions by using a laboratory type high‐speed thermo‐kinetic mixer. The effect of MG loading into PP on thermal conductivity and surface resistivity of PP was measured. With using MG as a conductive filler for PP, instead of GNP, through‐plane conductivity increased by 11%, however in‐plane conductivity decreased by 33%. Modified GNP‐filled PP showed better through‐plane conductivity and surface resistivity than those of unmodified GNP‐filled PP. Tensile and three point bending tests were performed to determine tensile and flexural properties of composites. Dynamic mechanical analysis was carried out to evaluate viscoelastic properties, such as storage modulus and loss modulus of composites. The thermal properties of samples were measured by using a differential scanning calorimetry, thermogravimetric analysis, and thermo‐mechanical analysis. Scanning electron microscopy was utilized to observe the fracture surfaces of the composites after tensile tests. POLYM. COMPOS., 40:E1320–E1328, 2019. © 2018 Society of Plastics Engineers

Fracture and fatigue behaviour of epoxy nanocomposites containing 1-D and 2-D nanoscale carbon fillers

The present paper describes improvements in the fracture resistance of epoxy polymers due to the addition of either (a) one-dimensional (1-D) carbon nanofibres (CNFs), or (b) two-dimensional (2-D) graphene nanoplatelets (GNPs), or (c) hybrid combinations of these carbon nanofillers (i.e. using both CNFs and GNPs). The effects of the dimensional shape and concentration (i.e. 0.0, 0.5, 1.0, 1.5 and 2.0 wt%) of the nanoscale carbon fillers are considered. The addition of CNFs, GNPs or hybrid combinations of CNFs and GNPs increases greatly the quasi-static fracture energy, GIc, of the epoxy due to these nanofillers inducing multiple intrinsic (e.g. interfacial debonding and void growth) and extrinsic (e.g. pull-out and bridging) toughening mechanisms. A mechanistic model is presented to quantify the contributions from the different toughening mechanisms induced by the CNF and the GNP fillers which result in the improvements observed in the fracture energy. The resistance of the epoxy, modified with either the GNPs or the CNFs, to cyclic-fatigue loading is also increased by the presence of the carbon nanofillers.