Rapid innovation in nanotechnology in recent years enabled development of advanced metal matrix nanocomposites for structural engineering and functional devices. Carbonous materials, such as graphite, carbon nanotubes (CNT's), and graphene possess unique electrical, mechanical, and thermal properties. Owe to their lubricious nature, these carbonous materials have attracted researchers to synthesize lightweight self-lubricating metal matrix nanocomposites with superior mechanical and tribological properties for several applications in automotive and aerospace industries. This review focuses on the recent development in mechanical and tribological behavior of self-lubricating metallic nanocomposites reinforced by carbonous nanomaterials such as CNT and graphene. The review includes development of self-lubricating nanocomposites, related issues in their processing, their characterization, and investigation of their tribological behavior. The results reveal that adding CNT and graphene to metals decreases both coefficient of friction and wear rate as well as increases the tensile strength. The mechanisms involved for the improved mechanical and tribological behavior is discussed.

Mechanical and tribological properties of self-lubricating metal matrix nanocomposites reinforced by carbon nanotubes (CNTs) and graphene – A review

Recent years have perceived many innovations in research and advancement of graphene, the thinnest two-dimensional atomic material. Graphene-based materials and their composites possess promising applications in wide range of fields such as, electronics, biomedical aids, membranes, flexible wearable sensors and actuators. The latest studies and progression in this subject area often produce inconsistent or inconclusive results. This review article assesses and summarises published data so as to provide a critical and comprehensive overview of state of the art. Firstly, the distinct structural nature of the graphene materials available is elucidated, as well as different production techniques available thus far. The assessment then discusses the various composites focusing different sub-functional regimes such as mechanical and collective functional applications such as energy, electronics biomedical, membranes and sensors. The utilisation of graphene and its derivatives in the manufacture of nanocomposites with different polymer matrices has been reconnoitred. Finally, a conclusion and perspective are given to discussing the remaining challenges for graphene nanocomposites in functional science and engineering.

Graphene-based materials and their composites: A review on production, applications and product limitations

In this review, recent progress in the mechanical, thermal and interfacial properties of graphene/CNT multiphase polymer composites is examined. Progress in the mechanical and thermal properties of CNT (1D) and graphene (2D) nanostructure materials is also reviewed and compared. Furthermore, this review highlights the improvements in the mechanical, thermal and interfacial properties of two- and three-phase composites, owing to the addition of graphene/CNT. In particular, analysis of several notable papers on hybrid composites (graphene/CNT) provides an intensive review of synergetic effects on the overall properties of the corresponding composites. This holistic review describes an improved interface between fibers and a nanofiller-reinforced matrix. Although the presence of nanofillers even at low loadings confers an overall improvement in composite properties, the exact ratios of individual fillers and combined forms remain to be discussed in depth. Finally, potential applications, current challenges and future perspectives for use of these multiphase composites are discussed with regard to their extraordinary capabilities and promising developments in graphene/CNT family-based composite materials.

Carbon nanotube- and graphene-reinforced multiphase polymeric composites: review on their properties and applications

The review presents a survey of the literature on structure–property relationships in epoxy-clay nanocomposites. Herein, various pivotal parameters affecting structures and properties of the nanocomposites including various types of modification as well as a vast range of available dispersion techniques were discussed. Opportunities and challenges in regards to potential applications of nanoclay in multi-scale composites have been also addressed. The multi-scale composites containing nanoclays have been reviewed in terms of mechanical properties in both out-of-plane and in-plane directions, and compared with those containing carbon based nanofillers. In this regards, the improving mechanisms in mechanical properties of both epoxy-clay nanocomposites and nanoclay filled fiber reinforced composites were also discussed.

A technical review on epoxy-clay nanocomposites: Structure, properties, and their applications in fiber reinforced composites

Directly grafting graphene oxide onto carbon fiber and the effect on the mechanical properties of carbon fiber composites

In this study, carbon fibers (CFs) were coated with graphene nanoplatelets (GnP), using a robust and continuous coating process. CFs were directly immersed in a stable GnP suspension and the coating conditions were optimized in order to obtain a high density of homogeneously and well-dispersed GnP. GnP coated CFs/epoxy composites were manufactured by a prepreg and lay-up method, and the mechanical properties and electrical conductivity of the composites were assessed. The GnP coated CFs/epoxy composites showed 52%, 7%, and 19% of increase in comparison with non-coated CFs/epoxy composites, for 90° flexural strength, 0° flexural strength and interlaminar shear strength, respectively. Meanwhile, incorporating GnP in the CF/epoxy interphase significantly improved the electrical conductivity through the thickness direction by creating a conductive path between the fibers.

Mechanical and electrical properties of carbon fiber composites with incorporation of graphene nanoplatelets at the fiber–matrix interphase

Nanoparticle modification of the carbon fiber–epoxy interface was investigated by depositing silicon dioxide (SiO2) nanoparticles on the surface of carbon fibers (CFs) using a conventional sizing process by immersing CFs tows in a SiO2 nanoparticle suspension. The surface density of the nanoparticles and the uniformity of their dispersion were characterized by scanning electron microscopy. CF–epoxy composites were fabricated to study the effect of the SiO2 nanoparticle coating on the CF–epoxy composite interfacial properties. Interfacial adhesion was assessed by measuring the interfacial shear strength (IFSS) with the single fiber fragmentation test. A 44% improvement of the IFSS was obtained with a SiO2 relative concentration of 1.3 wt%, compared with non-coated CFs. This increase was the result of an increase of the shear modulus of the matrix in the interphase region caused by the presence of the SiO2 nanoparticles. Coating CFs with SiO2 nanoparticles has been shown to be a simple, scalable, and cost effective method to increase the interfacial mechanical properties in CF–epoxy composites.

Modifying the carbon fiber–epoxy matrix interphase with silicon dioxide nanoparticles

In this study, a novel method consisting of coating carbon fibers (CF) with graphite nanoplatelets (GnP) is investigated for its ability to modify the mechanical properties in the interphase region. Coating the CF was achieved by immersing CF in a solution of GnP dispersed in an epoxy-based solution for a few seconds. The influence of the processing conditions on the properties of the coating (thickness, homogeneity, quality of the GnP dispersion) is reported. Interfacial adhesion and the associated failure modes were evaluated by the single fiber fragmentation test. The maximum value of interfacial shear strength (IFSS) was achieved when a relative GnP concentration of 7.9 wt% on CFs, which led to 45 and 34% improvements in IFSS in comparison with the non-coated CF and epoxy coated CF, respectively. POLYM. COMPOS., 37:1549–1556, 2016. © 2014 Society of Plastics Engineers

Modifying the carbon fiber–epoxy matrix interphase with graphite nanoplatelets

Functionalized silicon dioxide nanoparticles (nano-fSiO2) were uniformly deposited on the surface of carbon fibers (CFs) using a coating process which consisted of immersing the fibers directly in a suspension of nano-fSiO2 particles and epoxy monomers in 1-methyl-2-pyrrolidinone (NMP). The 0° flexural properties, 90° flexural properties, and Interlaminar shear strength (ILSS) mechanical properties of unidirectional epoxy composites made with nano-fSiO2+epoxy sized carbon fibers, with control fibers, and with epoxy-only sized fibers were measured and compared. An obvious increase of the fiber/matrix adherence strength was obtained with the nano-fSiO2+epoxy coating. The nano-fSiO2+epoxy sized CF/epoxy composites showed a relative increase of 15%, 50%, and 22% in comparison to control fibers, for the Interlaminar shear strength, the 90° flexural strength and the 90° flexural modulus, respectively but little e difference was measured between the different systems for the 0° flexural properties. The observation of the fracture surfaces by scanning electron microscopy of composite fracture confirmed the improvement of the interfacially dependent mechanical properties. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

Incorporation of silicon dioxide nanoparticles at the carbon fiber-epoxy matrix interphase and its effect on composite mechanical properties

With the use of composites expanding into larger structural applications, vinyl ester matrices which are not dependent on an autoclave cure and are more environmentally resistant to water absorption are being investigated. The degree of adhesion between the fiber and matrix has been recognized to be a critical factor in determining the performance of fiber-reinforced composites. The mechanical properties of carbon fiber–vinyl ester composites are low compared to carbon fiber–epoxy composites, partly because of lower interfacial adhesion. The origins of this limitation were investigated. The influence of preferential adsorption of the matrix constituents on the interfacial adhesion was not significant. However, the high cure volume shrinkage was found to be an important factor. An engineered interphase consisting of a partially cross-linked epoxy sizing that could chemically bond to the carbon fiber and form an interpenetrating network with the vinyl ester matrix was found to sharply improve the interfacial adhesion. The mechanisms involved in that improvement were investigated. The diffusion of styrene in the epoxy coating decreased the residual stress induced by the volume shrinkage of the vinyl ester matrix. The optimal value of the thickness was found to be a dominant factor in increasing the value of the interfacial shear strength according to a 2D non-linear finite element model.

Frederic Vautard

Papers

Mechanical and electrical properties of carbon fiber composites with incorporation of graphene nanoplatelets at the fiber–matrix interphase

Modifying the carbon fiber–epoxy matrix interphase with silicon dioxide nanoparticles

Modifying the carbon fiber–epoxy matrix interphase with graphite nanoplatelets

Incorporation of silicon dioxide nanoparticles at the carbon fiber-epoxy matrix interphase and its effect on composite mechanical properties

Carbon Fiber—Vinyl Ester Interfacial Adhesion Improvement by the Use of an Epoxy Coating