Multiscale hybrid composites with carbon-based nanofillers

Multiscale hybrid composites with carbon-based nanofillers

14


rgio Henrique Pezzin†, Christian Matheus dos Santos Cougo*, Se ‡ Wagner Mauricio Pachekoski , Sandro Campos Amico* *Materials Engineering Department, School of Engineering, Federal University of Rio Grande, Porto Alegre, Brazil, †Chemistry Department, Center for Technological Sciences, State University of Santa Catarina, Joinville, Brazil, ‡Mobility Engineering Department, Federal University of Santa Catarina, Campus Joinville, Joinville, Brazil

Chapter Outline 14.1 Introduction 449 14.2 Most used carbon-based nanofillers for multiscale composites 451 14.3 Manufacturing processes for multiscale hybrid composites 452 14.3.1 Thermosetting polymer matrices 452 14.3.2 Thermoplastic polymer composites 454

14.4 Mechanical properties of nanocarbon-based multiscale composites 14.5 Multifunctional characteristics of nanocarbon-based multiscale composites 459 14.6 Trends and future research 462 Acknowledgment 463 References 463

14.1

457

Introduction

The incorporation of reinforcements in polymers to obtain composites has attracted much interest due to the possibility of combining the advantages of reinforcements (e.g., stiffness and stability) with those of polymer matrices (e.g., flexibility and processability). The characteristics of these materials usually include low density and outstanding mechanical properties as well as high dimensional and thermal stability [1,2]. The use of “traditional” polymer composites, that is, fiber/matrix twocomponent systems, as structural materials was the basis of many technological breakthroughs in areas such as aerospace, automobiles, communications, construction, energy, and sports. Fiber-reinforced composites (FRC) have thus been largely studied by the research community in the last six decades [3–7]. Among the most used synthetic fibers, one can mention carbon fibers (CF) and glass fibers (GF), which are embedded into thermoplastic or thermosetting matrices [2,4]. Other relevant synthetic fibers are polymeric fibers such as aramid (AF) and Nanocarbon and its Composites. https://doi.org/10.1016/B978-0-08-102509-3.00014-6 © 2019 Elsevier Ltd. All rights reserved.

450

Nanocarbon and its Composites

ultrahigh molecular weight polyethylene (UHMWPE), ceramic fibers such as boron and silicon carbide, and more recently, basalt fibers, although much less has been reported on them in academic studies [4,8,9]. Carbon fibers are mostly polyacrylonitrile (PAN)-based fibers that went through a chemical modification process to obtain a highly oriented structure of bonded carbon atoms. CFs have very good properties such as low weight, dimensional stability, high stiffness, high strength, fatigue resistance, and low coefficient of thermal expansion. They are widely used in advanced composites for numerous applications, such as structural, automotive, and especially aerospace [7,10,11]. GFs are the most used reinforcement in polymer matrix composites, being classified into E-glass, R-Glass, and S-Glass, among others. E-glass is the most common type, mainly due its low cost, relatively high tensile strength (1.70–2.80 GPa), and chemical resistance. Their disadvantages when used in composites include a relatively low modulus (70–90 GPa), high abrasiveness, and low resistance to fatigue. Besides, they are electrically nonconductive and transparent to most electromagnetic radiation [12]. Polyaramid fibers, also known as aramid fibers, consist of poly(p-phenylene terephtlamide) (PPTA) and were developed by DuPont in the 1970s, being commercially introduced in 1972 by the trademark of Kevlar. Their highly oriented macromolecules promote the formation of secondary bonds between polymer chains, making it harder for the polymer chains to slide past each other, thus enhancing their mechanical properties. They present very good mechanical properties and are commonly known for their very high impact and abrasion resistance [13,14]. Recently, fibers obtained from basalt (a volcanic rock found on the surface of the Earth’s crust), mainly composed of SiO2 (40%–60%) and other oxides have come into consideration as reinforcements in composite materials. In addition to their good mechanical properties and excellent heat resistance, these fibers present very good sound and heat insulation and vibration-damping properties [15]. More detailed information about basalt fiber composites can be found in reviews such as those by Fiore [16] and Dhand [17]. Although FRCs have achieved outstanding recognition, some properties are still considered unsatisfactory, especially those more closely related to the matrix, and the lack of some less usual characteristics that may be required in some applications, such as electrical conductivity. Meanwhile, the advances in the field of nanotechnology and the unique attributes of nanomaterials have brought some interesting new possibilities into the materials field. Their use as fillers for polymers has been vastly studied in the past few decades, although the results have been limited in some areas. Thus, it has been proposed to combine these two fields, that is, to use microscale fibers together with nanoscale fillers to achieve composites with a very wide range of characteristics [18–20]. On this context, this chapter focuses on the development and application of synthetic fiber composites containing CNP. It briefly presents the main carbon nanofillers and some important characteristics and reviews some of the manufacturing processes available to obtain multiscale hybrid thermoplastic or thermosetting composites. It also describes the use of these nanofillers to add or improve mechanical-related properties of composites and other properties, such as electromagnetic and thermal, and presents some applications and future trends.

Multiscale hybrid composites with carbon-based nanofillers

14.2

451

Most used carbon-based nanofillers for multiscale composites

To discuss in detail the nanofillers available, their synthesis and properties are beyond the scope of this chapter. Nevertheless, the most used CNPs for composites are briefly mentioned in this section. Due to their small size, outstanding mechanical resistance, and high thermal and electrical conductivities, carbon nanoparticles (e.g., graphene, nanoplatelets, nanotubes, nanofibers, nanocarbon black), are mentioned as the ultimate reinforcement for the production of high-performance multifunctional composites. Carbon nanotubes (CNTs) are tubular structures made of carbon atoms with sp2 hybridization [21]. Although very similar to graphite, these structures are highly isotropic, and with really outstanding mechanical strength and toughness, electrical and thermal conductivities, and low density [22]. CNTs can be classified into two groups: single-walled carbon nanotubes (SWCNT), consisting of a single graphite sheet wrapped into a cylindrical tube with a diameter in the 0.7–3 nm range, and multiwalled carbon nanotubes (MWCNT), composed of more than two coaxial cylinders, each rolled out of single sheets, with a 2–40 nm diameter. Generally, MWCNTs are preferred for application in composites because SWCNTs are more expensive and more difficult to disperse. The CNT type, quality, aspect ratio, and impurities are decisive to the final properties of CNT-reinforced composites. There are a great number of papers and reviews in the literature discussing the properties that may be obtained by CNT/ polymeric matrix composites [23,24]. In general, CNTs can provide both intra- and interlaminar reinforcement, thus improving delamination resistance and reducing limitations associated with matrix-dominated properties [25]. Electrical conductivity in CNT nanocomposites is generally explained by the formation of a CNT network, allowing the percolation of electrical currents through the material. Even at low concentrations (<1 wt%), CNTs can increase the bulk conductivity of epoxy matrices from 10
9 to 10
1 S/m [26,27]. Novoselov [28] obtained monocrystalline graphitic films with the thickness of only a few atoms by mechanical exfoliation of small particles of highly oriented pyrolytic graphite. Single graphene sheets may have a Young’s modulus and strength greater than those of SWCNTs and are also electrically conductive [29]. The films with multiple layers on top of each other, interacting by van der Waals forces, are commonly known as graphene nanoplatelets or graphite nanoplatelets (GNPs), depending on the number of layers that constitute the material. These films also have excellent mechanical, electromagnetic, thermal, and optical properties [30]. Similarly to CNTs, graphene sheets can be used as reinforcements for the improvement of mechanical and electrical properties in composite materials [31]. Among the variety of carbon-based nanoparticles available, carbon black and fullerenes are also worth mentioning. Carbon blacks (CBs) are a carbon particle of the micro and nanoscale produced by thermal decomposition or partial combustion of hydrocarbons. They present a complex structure consisting of multiple spherical particles fused together and come as a low-cost filler option to enhance some mechanical

452

Nanocarbon and its Composites

and electrical properties. Developed around the mid-1980s, fullerenes consist of geometric cage-like structures of carbon atoms formed by pentagonal and hexagonal faces and are usually classified by the number of carbon atoms in the structure [32]. Due to their very high aspect ratio, nanoparticles have high surface energy and tend to agglomerate, forming aggregates when added to a polymeric matrix. This is aggravated by a generally poor interface bonding with polymer molecular chains [23]. Indeed, poor dispersion and low adhesion of CNP in polymer matrices still need to be tackled if the utmost potentiality of CNP/polymer composites is to be achieved [33]. The state of dispersion of the nanoparticles in the polymer matrix is decisive and, in an ideal situation, nanoparticles would not create large stress concentrations that compromise the ductility of the nanocomposite due to their reduced sizes. A further concern is that, when increasing the volume fraction of micro- or nanoreinforcements, they are more prone to aggregate [34]. An alternative approach to tackle the homogeneity and interfacial interaction issues in nanocomposites involves functionalization of the surface of the nanofiller with functional groups that strongly interact or form covalent bonds with the molecular chains of the matrix [33]. There is extensive literature about the functionalization of nanofillers for polymeric nanocomposites and the same strategies are used when dealing with multiscale composites. An interesting option is to functionalize the nanoparticle with a chemical species identical to those of the host matrix. For instance, Sainsbury [35] functionalized MWCNTs with PPTA, and the treated nanofiller showed much better results integrating with the PPTA polymer.

14.3

Manufacturing processes for multiscale hybrid composites

14.3.1 Thermosetting polymer matrices The insertion of nanofillers in thermosetting matrix composites can be done by adding the nanofiller directly into the polymeric resin (or the hardener), followed by a dispersion method, then proceeding to molding the composite by casting, for instance. The nanofiller can also be previously dispersed in a solvent system that usually has lower viscosity and better compatibility, and later introduced into the resin or hardener. The two most used dispersion methods are sonication and high shear mixing. The nanofiller/resin mixture is then used as a conventional resin in the chosen composite molding technique. There are a few reviews in the literature about the techniques and parameters of dispersion of carbon-based nanofillers in polymeric matrices, such as Xie [23], Ma [36], and Wei [37]. There are a few issues that deserve attention regarding those dispersion methods, namely, the effect of the nanofillers on the rheological properties of the resin, which may complicate resin flow, the reagglomeration of nanofillers, the heterogeneous distribution of nanoparticles, and the possible degradation of nanofillers or the resin during the ultrasonication or shear mixing procedure. The composite molding process used afterward will also affect material performance because it will define the

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orientation and distribution of nanoparticles in the composite. For instance, Tan [38] used compression molding to orient GNPs parallel to the compression surface in a polyaramid woven composite and reported an increase in its tensile properties. There are a few approaches to bypass the need to insert the nanofillers into the resin, such as using the nanofillers on the sizing, growing the nanoparticles directly on the fiber, or producing layers of the desired nanoparticles, such as thin films or buckypapers. The simple introduction of nanofillers on the fiber sizing has as yet received limited attention in the literature. A GO-modified fiber sizing was produced by Zhang [39] by pulling unsized CF through an epoxy solution (1.5 wt%) with varied content of GO sheets, and later drying it to remove water. The results showed an increase in the fiber/epoxy interfacial shear strength of 70.9% and 36.3% for the untreated fiber that received the GO coating and for the fiber treated with the commercial sizing, respectively. Warrier [40] used three-roll mixing to add 0.5 wt% CNTs to the GF sizing for composites with epoxy. The mode-I interlaminar fracture toughness at crack initiation showed an increase for all the CNT-enhanced composites, but a decrease was noticed in crack propagation fracture toughness, probably due to the bundling of fibers. Also, the CNT dispersed directly into the matrix reached better results, probably because the CNT sizing was placed over the commercial sizing already present in the fiber. Some other papers report on the deposition of nanoparticles directly onto the surface of fibers by electrophoretic deposition (EPD) or chemical vapor deposition (CVD). Guo [41] used ultrasonically assisted EPD to produce CNT-enhanced CF. They dispersed the CNTs in deionized water by ultrasonication, then fixed CF in a plastic frame using a conductive adhesive and inserted into an EPD cell containing the CNT suspension. After that, a graphite plate was placed on the opposite side of the carbon fiber as the counterelectrode. This was considered a promising method, reaching a good and uniform amount of deposited CNTs. The CVD technique can also be used to grow nanoparticles directly on the fiber surface. However, the fiber thermal stability must be taken into consideration because this method comprises high temperature and the presence of chemical reacting species on the controlled atmosphere. These conditions may cause fiber degradation due to the appearance of mechanical defects or due to the loss of organic material or organic sizing present on the fiber. Sager [42] produced CF with CVD-grown CNTs and obtained radially aligned and randomly oriented CNTs with respect to the fiber surface. The CNTs yielded an increase in interfacial shear strength of 71% and 11%, respectively, but with a decrease in fiber tensile strength in both samples, which was attributed to fiber degradation and the insertion of surface flaws during the CVD process. The CNT growth conditions also affect the final properties. Zhang [10] reported that the temperature of the CVD process significantly affected the fiber tensile properties, whereas the process time did not. They also mentioned that the unsized CF was able to withstand greater temperatures than the sized fiber. The fiber itself may also influence the nanoparticle growth by interacting with the catalyst. Rahmanian [43] investigated the influence of CNTs grown directly on GF and CF, and reported that the CNTs grown on the GF had a larger diameter than those grown on CF.

454

Nanocarbon and its Composites

As mentioned above, another route consists of producing thin films or buckypaper of the nanofillers and using them as interplies to assemble the hybrid laminate, which is later processed using a more common technique. Through stretching and pressing of the CNT film, it is possible to obtain a highly aligned sheet, dramatically increasing its properties [44]. This would make it easier to obtain composites with higher nanofiller content than via dispersion in the matrix. There are a few processes available to obtain such CNT thin films. Garcia [45] developed a technique that consists of growing vertically aligned CNTs in a silicon substrate and mechanically transplanting the CNT “forest” to tacky CF prepreg layers using a rolling cylinder. Khan [20] used interleaves of carbon nanofiber buckypaper to improve the interlaminar shear properties of the CF composite. Wang [46] presented two methods for the manufacturing of CNT interply composites: the first one comprised the stacking of fabrics and buckypaper and their impregnation with a resin through vacuum infusion, and the other one the compression of prepregs and buckypaper together so that the resin flows through the buckypaper. Pan [47], on the other hand, produced a CNT film using a freestanding floating catalyst CVD, a commercially available process, which enabled them to obtain a CF composite with high CNT content, up to 21%. Analogously to buckypaper produced with CNTs, thick GO paper can be produced by filtration and later used in an assembly to produce the hybrid multiscale composite, as performed by Ning [48].

14.3.2 Thermoplastic polymer composites Table 14.1 summarizes some of the work on manufacturing processes used to obtain thermoplastic multiscale composites. The two wide approaches used to prepare multiscale (fiber/nanoparticle/polymer) thermoplastic composites are discussed below. (i) Addition of nanoparticles in the polymer/fiber system by melt mixing:

The dispersion of nanoparticles in the polymer melt is the most common route, although it is normally restricted to systems consisting of short fibers and polymers with relatively low viscosity. Although scalable at an industrial level, it is typically limited to low volume fractions (2%) of CNP due to the resulting significant increase in viscosity [52]. For high-viscosity polymers, processing is usually by hot pressing (compression molding), with the polymer/CNP mixture being used to impregnate the fibers. This was employed by Dı´ez-Pascual [68] and Ashrafi [53] for the preparation of poly(ether ether ketone) (PEEK)/GF/SWCNT, and by Shen [54] for polyamide-6 (PA-6)/GF/MWCNT composites, but with only moderate enhancement in the tensile and flexural properties, probably due to dispersion issues. The use of a compatibilizer is mentioned as an alternative to mitigate this problem and improve composite ductility [68]. PA-6/basalt fiber/MWCNT hybrid systems were prepared by extrusion and injection molding by Meszaros [56]. The combination of microscopic (30 wt% of basalt fibers) and nanosized (0.5–2 wt% of CNT) reinforcements significantly improved the mechanical properties, and synergistic effects were also reported. Kim [69]

Multiscale hybrid composites with carbon-based nanofillers

455

Table 14.1 Compilation of references on multiscale thermoplastic composites Method of CNP addition

Matrix

Fiber

CNP

PP

GF

SWCNT/ MWCNT

Dispersion on sizing

PEEK

GF

SWCNT

Dispersion on the melt (hot pressing)

PA-6

GF

MWCNT

PI PA-6

CF Basalt

MWCNT MWCNT

PI

CF

MWCNT

PA-6

GF

MWCNT

PPEK

CF

MWCNT

PP

MWCNT

PMMA PP PI PP

CF and GF CF CF CF Aramid

PI

CF

Dispersion on the melt (hot pressing) Dispersion on the melt Dispersion on the melt (extrusion/injection molding) Dispersion on the melt (hot molding) Electrophoretic deposition Electrophoretic deposition CVD-growth on CF and GF CVD-growth on CF CVD-growth on CF CVD-growth on CF Chemical reaction between functionalized CNT and fibers Dispersion on the melt

Li [64]

PEN PES PP

CF CF CF

Melt mixing Dispersion on coating Dispersion on coating

Yang [65] Li [66] Luo [67]

MWCNT MWCNT MWCNT MWCNT

Functionalized MWCNT GNPs GO GO

Reference Barber [49], M€ader [50], and Rausch [51] Dı´ez-Pascual [52] and Ashrafi [53] Shen [54] Zhang [55] Meszaros [56]

Rong [57] Zhang [58] Zhang [59] Rahmanian [43] Qian [60] Suraya [61] Su [62] Gonzales-Chi [63]

PA, polyamide; PEEK, poly(ether ether ketone); PEN, poly(ethylene naphthalate); PES, poly(ether sulfide); PI, polyimide; PMMA, poly(methyl methacrylate); PP, polypropylene; PPEK, poly(phthalazinone ether ketone).

used a twin-screw extruder to disperse short carbon fibers (diameter ¼ 8 μm, length ¼ 6 mm) and CNTs in polypropylene (PP). The addition of MWCNTs increased electrical conductivity as well as tensile strength and flexural modulus. However, the impact strength decreased, probably due to the necessary torque increase in the extruder that decreased the CF length. A random arrangement of CNPs is expected by this melt-mixing approach, although most of the studies did not report the CNP orientation. Nevertheless, there is some concern about how the microscale fibers affect the hierarchical self-assembly

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Nanocarbon and its Composites

of nanoparticles during mixing [33]. Also, the role of shear during melt mixing is still controversial, and while most authors report the breakdown of clusters and agglomerates by high shear [70], the promotion of ordered states is also a possibility [71]. (ii) Prior placement or growth of nanoparticles on the fibers:

Multiscale composites can also be prepared by hierarchical fiber-nanoparticle arrangement, that is, carbon nanoparticles (CNP) can be placed or grown onto fibers, allowing a much higher CNP content. Different techniques fit into this classification, including: l

l

l

l

l

Direct placement of CNP onto the fibers (by spraying, painting, or sonication) or in an interphase between composite plies (Zhu [72]; Abot [73]; Gnidakouong [74]; Li [75]; Silva [76]; Ku-Herrera [77]). Electrophoretic deposition onto the surface of fabric layers (Bekyarova [78]; Zhang [58]; Haghbin [79]). Coating of fibers with sizing agents modified with CNP (Barber [49]; M€ader [50]; Rausch [51]; Wang [80]). Growth of CNT onto CF or GF fibers by chemical or thermal vapor deposition (CVD or TVD) (Qian [60]; Rahmanian [43]; Naito [81]) or via graphitic structures by design (GSD) (Tehrani [82]). Chemical reactions between functionalized CNP and fibers (Qian [60]).

There is also the possibility of combining different methods to achieve optimized results. For instance, Zhou [83] showed, by experimental and numerical techniques, that the effect of MWCNT addition on the strength and fracture behavior is more effective when a small MWCNT content dispersed in the polymer matrix is associated with a fiber sizing with high MWCNT content. Also, Zhang [59] proposed an easy method to prepare MWCNT/CF by combining electrophoretic deposition with a sizing process. The introduction of MWCNT in the CF/PPEK composites resulted in a 35.6% increase in IFSS. Although most of these methods were applied to systems comprised of carbon or glass fibers and multiwalled carbon nanotubes (MWCNT), they can be useful for different fiber/CNP combinations (with the exception of the direct growth of carbon nanostructures onto fibers, which is restricted to CF, GF, and ceramic fibers). Nevertheless, these methods are generally used with thermosetting resins and there are limitations when they are applied to high-viscosity thermoplastic systems. It must also be taken into account that multiscale reinforcement depends on the CNP type, concentration, and surface chemistry for the improvement of fiber-polymer interphases [25]. The placement of CNP directly onto the fibers (as in spray coating, conventional painting, electrophoresis, or sonication) and the dispersion of CNP on sizing agents avoid any possible damage to the fibers that can occur during CVD growth, which demands high temperatures (>550 °C). However, with these methods, the CNPs are, in general, weakly (noncovalently) connected to the fibers and it can be difficult to control their orientation. Even so, significant improvement in storage modulus was reported for a PA-6/GF/MWCNT laminate prepared by deposition of a very low content of oxidized CNT (0.18 wt%) on the fiber [58]. This was credited to a fiber-matrix interconnecting effect, as the GF/MWCNT formed a porous structure that could be

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easily interpenetrated by the polymer, resulting in strong fiber-matrix interfacial adhesion. Dispersion of CNP in the sizing protects the fiber surface and improves stress transfer at the interface [51]. This approach also permits further processing by extrusion, injection molding, compression molding, melt spinning, and other thermoplastic melt processing techniques [49–51]. On the other hand, CVDs or GSDs provide a much better attachment and arrangement of carbon nanotubes around the fibers, but these methods are more difficult to scale up. An interesting effect shown for PP hierarchical composites (CVD growth of MWCNT on CF or GF) is that CNTs act as nucleation sites on the fiber surface, promoting the formation of a transcrystalline layer around the GF, which considerably improves tensile and flexural properties [43,61,69]. Recently, Gonzales-Chi [63] reported the processing of multiscale composites based on PP reinforced with aramid fibers chemically treated with acid solutions and coated with oxidized MWCNT. The results showed an increase in interfacial shear strength (IFSS), suggesting physicochemical interactions among fibers, MWCNT, and PP in addition to mechanical interlocking. More comprehensive information about the manufacturing of hierarchical thermoplastic composites can be found in the review by Dı´ez-Pascual [84].

14.4

Mechanical properties of nanocarbon-based multiscale composites

Efforts to develop composite materials with advanced mechanical properties have been a matter of study for a very long time. But even using the most advanced fibers available, the matrix still has relatively poor mechanical properties that can affect the composite performance in some cases. Thus, the discussed carbon nanofillers may improve the matrix-dominant properties and the fiber/matrix interfacial bonding. Although most studies concentrate on matrix-dominant properties, there are many studies focusing on the influence of the nanoparticles on the tensile, flexural, and compressive behavior of composites. Depending on the manufacturing process and the process parameters, the results may significantly vary because the nanofiller can be placed on the fiber interface, in the matrix, or between the composite ply. Rahmanian [43] studied the influence of CNTs on short GF and CF/PP composites. The CNTs grown on the fiber surface acted to enhance the stress transfer between the fiber and matrix, significantly improving tensile modulus (40% and 57% for GF and CF, respectively) and flexural modulus (36% and 51% for GF and CF, respectively). The interlaminar properties of the composite are perhaps the focus of most papers on multiscale hybrid composites. Pedrazzoli [85] used expanded GNPs (xGNPs) as coupling agents on a GF/PP composite. The xGNPs were introduced in the PP matrix, with and without the use of a compatibilizer (maleic anhydride), and a single fiber fragmentation test was performed. The presence of 7 wt% xGNPs significantly increased the fiber/matrix interfacial adhesion, from 2.7 to 16.4 MPa, with an increase in shear modulus of 44%. With the combined use of the compatibilizer, the increase

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Nanocarbon and its Composites

was even higher, obtaining 98% improvement in shear modulus and an interfacial adhesion of 39 MPa. Veedu [86] produced multiscale hybrid composites by growing MWCNTs perpendicular to SiC fiber-woven fabrics through CVD and later infiltrated the reinforcement with an epoxy matrix. They obtained a 348% increase in mode I fracture toughness and 54% in mode II fracture toughness. Ogasawara [87] obtained an improvement of 60% in the interlaminar fracture toughness of CFRP composites by adding 0.5 wt% of fullerenes into epoxy, which was later used to produce CF prepreg. Godara [88] worked on CF prepregs and dispersed 0.5 wt% of MWCNTs, thin MWCNTs (TWCNTs), and amine-functionalized DWCNTs through high-shear calendaring. The multiscale composite presented a substantial decrease in the coefficient of thermal expansion (CTE) and crack initiation and propagation presented a significant improvement, especially for the functionalized nanofillers, mainly due to fiber bridging by the CNTs. For further information on the influence of nanoparticles in interlaminar fracture toughness, one can refer to the review by Tang [89]. The fatigue resistance is another important mechanical property for advanced composites and the possibility to enhance it has received a lot of attention lately. Grimmer [90] studied the effect of 1 wt% of CNTs in a GF/epoxy composite response in a cyclic double cantilever beam flexural test and cyclic mode I delamination. The experiments showed a decrease in the rate of crack propagation with the CNTs, justified by the appearance of nanotube pullout and fracture. Li [91] investigated the creep behavior of a multiscale MWCNT/fiber/matrix composite and found an optimum amount of MWCNTs to decrease the creep strain rate. Indeed, the creep and glass transition temperature (Tg) characteristics are essentially related to the interaction between resin and reinforcement and its influence on the movement of polymer chains. Therefore, it is expected that nanofillers present in the matrix may also affect these characteristics. There are also several studies reporting the synergistic effects between microscale fibers and nanofillers, especially for carbon-based nanofillers and CFs. Using 5 wt% GNPs in a CF/poly(arylene ether nitrile) (PEN) composite, Yang [65] achieved increments in flexural strength of 98.4% and 63.6% and flexural modulus of 4.5 and 1.7 times compared with the bicomponent GNP/PEN and CF/PEN composites, respectively. The impact and postimpact properties of conventional composites can also be enhanced by carbon-based nanofillers. Siegfried [92] used epoxy with 0.25 wt% of pristine, aged, and NH2-functionalized MWCNTs to produce CF woven composites by RTM. The composites were then evaluated in interlaminar shear strength, mode II interlaminar fracture toughness, drop weight, and compression after impact tests. The samples containing CNTs presented a slight increase in mode II fracture toughness. The aged batch used in this study presented a network-like structure of CNT agglomerates in the resin, which was responsible for maintaining CAI strength, differently from the other batches. In addition, all samples containing CNTs presented an increase in the delaminated area but with little change in interlaminar shear strength. Taraghi [93] examined the low-velocity impact response of Kevlar/epoxy composites with CNTs (from 0 to 1 wt%) added through high shear mixing followed by ultrasonication

Multiscale hybrid composites with carbon-based nanofillers

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in the resin. The study showed an increase of 35% in impact energy absorbed by the composite with 0.5 wt% of CNTs, which decreased for higher CNT content due to possible nanofiller agglomeration. The composite response to high strain rate deformation and the related energy absorption in a ballistic impact, for instance, can also be improved using nanocarbon as filler. When a high-velocity impact occurs, there is a propagation of shockwaves through the material and an amount of energy is converted into vibration. In this case, the presence of the nanofiller can aid in the dissipation of vibration by acting as a network of spring dampers, enhancing the damping capability of the composite [94,95]. Manero [96] reported an increment in the ballistic protection performance of Kevlar 29/epoxy composites filled with different types of nanoparticles. Micheli [97] added 1 wt% of CNTs through solvent ultrasonication to a hybrid Kevlar/CF/epoxy composite and investigated its ballistic performance. By evaluating the damage area caused by the projectile, they concluded that the CNTs improved the ballistic performance, aiding impact energy propagation through the plate. However, the effect of the nanofillers is not always positive. Grujicic [98] investigated the ballistic-protection performance of a GF/poly-vinyl-ester-epoxy (PVEE) composite containing MWCNT in the matrix. The reinforcement consisted of E-glass fiber in the form of mats and the composite was produced through vacuumassisted RTM. In this study, the presence of the CNTs did not show significant improvement in the ballistic performance. This was attributed to the short length of the MWCNTs, which renders the fiber pullout mechanism ineffective regarding energy absorption. This is probably due to the formation of an overlayer on the outer wall of the MWCNTs that is not capable of propagating stress, with a detrimental effect on the absorption of the impact’s kinetic energy (through delamination and/ or fiber pullout) or the mechanism of erosion/fragmentation of the projectile.

14.5

Multifunctional characteristics of nanocarbon-based multiscale composites

A multifunctional composite must combine a load bearing capability with functional properties such as thermal, electrical, electromagnetic, or health sensoring. Because conventional long fiber composites are already capable of sustaining high loads, the multifunctional properties are usually expected to come from the nanofillers. This kind of material is of extreme interest to specialized fields such as aerospace and military because the combination of properties in the same material may bring a significant improvement in efficiency due to the reduction in mass and/or volume of the total system. In particular, the effect of carbon nanofillers on the thermal and electrical properties of conventional fiber-reinforced polymer composites has been largely investigated. Indeed, because carbon-based nanofillers tend to present high thermal conductivity and low (or even negative) CTE, an adequate dispersion/positioning of the nanofiller in the matrix will most likely bring such features. A significant decrease in CTE means that thermomechanical stresses may be significantly reduced. At the same time, the

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thermal conductivity of the composites tends to increase [99]. A well-dispersed network will promote thermal conductivity or stability throughout the whole material, and this is achieved by planning the appropriate alignment, assembling, or positioning of the nanofillers. In fact, it is also possible to produce composites with very distinct thermal characteristics in different directions. Veedu [86] reported a significant increase in through-the-thickness thermal conductivity in a CVD-grown MWCNT/GF/epoxy prepreg composite. Wang [100] found that the inclusion of 3 wt% CNT into low-viscosity polyester/vinyl ester/glass fiber composites resulted in a 1.5-fold increase in thermal conductivity. Noh [101] studied the thermal conductivity of a multiscale composite containing short CF and GNPs in a cyclic butylene terephthalate matrix. The composite was prepared through powder mixing followed by heat compression. The isotropic in-plane thermal conductivity was maximized (183% increase) in the composite containing 5 wt% of CF and 15 wt% of graphene. The synergistic improvement was credited to more efficient thermally conductive pathways and internal structures favoring phonon transport. The synergistic behavior was also mentioned in the study of Yang [65], who revealed that multiscale carbon fiber/poly (arylene ether nitrile) (CF/PEN) filled with graphene (5 wt%) was 80 °C more thermally stable than the PEN/CF bicomponent composite. Carbon nanotubes (1 wt%) were found to cause a 25% reduction in CTE in glassfiber/epoxy composites [102]. Godara [88] evaluated the influence of 0.5 wt% CNTs on the thermal properties of epoxy CF prepregs. They found a significant decrease (32%) in CTE for the functionalized DWCNTs and TMWCNTs, but not for MWCNTs, which was justified by the greater interaction of the DWCNTs and TMWCNTs with the polymer chains due to their reduced size and better dispersion on the matrix. Regarding thermal stability, Yang [65] reported an enhancement when using GNPs in CF/PEN composites. Pedrazzoli [85] also found that the addition of xGNPs promoted a significant increase in both the onset (Td,onset) and maximum (Td,max) degradation temperature of the matrix, which were further increased by using a compatibilizer, probably due to better dispersion and exfoliation of the nanolayers. This showed an interesting thermal shielding aspect. Because most polymer composites lack electrical conductivity or are insulating, except when CFs are used, the addition of carbon nanofillers has been widely used to improve this aspect of the material, as in the work of Veedu [86], who reported a great improvement in through-the-thickness electrical conductivity from 0.075 10
5 to 0.408 S/cm. Improvement in the electrical conductivity of CNT/glass fiber/epoxy derives from the strong network-forming ability of CNTs above a critical percolation threshold, which is well known in pure nanocomposite systems [99]. The glass-fiber-reinforced epoxy composites containing 0.3 wt% of carbon nanotubes exhibit relatively high electrical conductivity, which enables functional properties such as stress-strain monitoring and damage detection [103]. A high degree of electrical anisotropy has been reported for hierarchical composites based on glass fibers. Conductivity in the primary fiber direction was about an order of magnitude higher than in the transverse direction, reaching values of 1 S/m (from 10
11 S/m) at only 0.01 wt% CNT [104]. Gojny [105] also reported

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in-plane conductivity one order of magnitude higher than that out of plane. According to Qiu [102], the improvement in electrical conductivity indicates a way to leverage the benefits of CNTs and opens new opportunities for high-performance multifunctional multiscale composites. Qin [106], incorporating graphene nanoplatelets into a carbon fiber/epoxy interphase, significantly improved the through-the-thickness electrical conductivity by creating a conductive path between the fibers. Carbon black (CB) is one of the most widely used conductive additives in polymers. The overall conductivity of a filled polymer system sharply increases when a sufficient amount of CB, required for the construction of 3D conductive networks, is added. However, the amount of CB required to achieve high levels of composite conductivity is comparatively high. Thus, the combination of carbon black and conductive fillers has been proposed as a way to alter both the percolation threshold and the conductivity levels [107]. The influence of carbon black and recycled short carbon fibers on the electrical properties of unidirectional glass-fiber-reinforced polyethylene has been investigated by Markov [108]. Anisotropy in electrical conductivity was only observed in the percolation threshold range because this threshold is preferentially concentrated along the fibers. Drubetski [107] studied the electrical conductivity and morphology of injection-molded PP-based composites containing CB and CFs, both above their percolation threshold. The results presented similar or even lower values than those systems filled only with CB at the corresponding content, and resistivity of the two-filler systems was always higher than that of systems filled only with CF. In spite of the mechanical disturbances caused by the presence of fibrous and particulate fillers, the coexistence of CB and CF electrically conductive networks supporting each other was confirmed. A similar behavior was found by Shen [109], who prepared high-density polyethylene (HDPE) with CB and CF, and HDPE/PP polymer blends with those fillers. The combined use of CB (ca. 2–37 wt%) and CF (2 wt%) produced a performance inferior to that of HDPE/CB and HDPE/PP/CB, respectively, at the same total filler content. In both composites, electrons are transported over long distances by CFs with little energy loss, whereas CB particles improve the interfiber contact by forming CB particle bridges. The hierarchical design of multiscale high performance composite materials (advanced polymers, fibers, and carbon nanoreinforcements) allows the production of hybrid composites with special radiation shielding properties. Electromagnetic shielding refers to the attenuation, in reflection and/or absorption, of electromagnetic radiation due to the use of a material that acts as a “shield” against it. These materials may be used to protect electrical circuits and equipment that are subject to disturbances due to external electromagnetic radiation that interfere with their operation. As an example, glass fiber composites combined with materials of high dielectric and/or magnetic losses, such as CNT and GNP, can behave as efficient microwave absorbers, being useful for protective structures for radar data transmission antenna systems and in aircraft radomes [76]. The wide range of applications includes materials for electromagnetic shielding (EMI), electrostatic discharge (ESD) protection, special adhesives, and conducting coverings. Silva [76] sonicated CNTs on acetone and deposited the mixture directly onto GF fabrics before molding the multiscale

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composite through RTM. They also investigated the effect of dispersing the CNTs in the resin (also by sonication) prior to the RTM. Reaching up to 4.15 wt% of CNT, the final composite was able to obtain a maximum electromagnetic attenuation of 98.5% in the microwave frequency. A downside in the use of polymeric composites in structural applications has always been the difficulty in monitoring their structural health because composites do not usually show signs of deterioration until just before they actually fail. A possible means of monitoring the actual state of these materials is to use nondestructive evaluation methods such as scan-based techniques, but they present several complications due to the dimensions of the equipment and the limited monitoring capability. An alternative approach rests in monitoring changes in the electrical conductive behavior of the material whenever it has sustained internal or nonvisible damage. Because most polymeric composites lack electrical conductivity, except CF-based composites that present some anisotropic conductivity, it is necessary to use other agents to promote this characteristic. For instance, B€oger [110] incorporated DWCNTs, MWCNTs, and CB into epoxy using three-roll mixing and later produced the tricomponent GF composite through vacuum-assisted RTM. The authors proposed to evaluate composite integrity during interlaminar shear strength as well as static and dynamic tests by measuring its in situ electrical resistance on both in-plane and out-ofplane directions. The method offered a possibility to evaluate damage accumulation in situ during fatigue tests and showed an interesting correlation between the strain state of the composite and its electrical resistance, allowing a more extensive comprehension of its structural integrity. Sebastian [111] produced different sets of CNTgrown GF bundles and introduced them in the composite to act as strain-monitoring systems based on the variation in electrical resistivity response of the bundles with stress. These GF sensors exhibited sensitivity similar to those of conventional metal foil strain gauges, with a prominent advantage of having the sensor embedded in the composite. Nevertheless, further studies to fully comprehend the interaction between tensile, compression, or shear stresses and electrical resistivity response of multiscale materials are still necessary.

14.6

Trends and future research

In these multiscale hybrid composites with carbon-based nanofillers, there is the possibility of taking advantage of the nanofiller’s thermal and electric properties to cure the polymeric matrix in situ. For instance, Xu [112] produced laminates using a single CNT sheet with glass fiber prepregs. The heating of this sheet through an electric current enabled a much faster and more energy-efficient curing process of the prepreg compared to the conventional oven process. Nguyen [113] also reported good results in the use of CNT sheets in a CF/bismaleimide composite to enable its in situ curing. The combined use of carbon-based nanofillers and fibers for multifunctional composites for energy-related devices is getting a lot of attention and is likely to receive even more in the coming years. As their electrical properties seem to show a synergistic effect, these properties being present in a structural material is very interesting

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for several industry fields [114]. Their use for energy storage systems, such as capacitors with great mechanical properties, is another application receiving increasing attention. Islam [115] grafted CNTs onto the surface of CF and evaluated the mechanical and capacitance properties, and found 3.5 times greater specific capacitance with the insertion of CNTs. In another work, Xiong [116] used both EPD and CVD methods to fabricate a 3D GO/CNT/CF laminate for application as an electrode. The material presented a specific capacitance that was four times higher than pure CF. Another field that has been growing related to multiscale hybrid composites refers to the incorporation of a combination of nanoparticles, for example, CNPs with metallic nanoparticles or nanoclays or even hybridization using CNPs alone. For instance, Kwon [117] evaluated both CNT and GNP for the improvement in interfacial adhesion between epoxy and the reinforcement. Gao [118] grafted GO and CNTs onto the surface of CF and found that the presence of the CNPs increased fiber surface area and wettability. The multiscale composite presented superior interlaminar and interfacial shear strength compared to the CF fiber alone. A possible drawback related to these multiscale materials refers to their recycling. Indeed, recycling long fiber composites is already a complex task, and the introduction of nanofillers makes it even more complicated because they usually require special considerations due to potential toxicity and other health-related issues. Therefore, there is a broad field of research for recycling and proper disposal of these [119]. A key point for the commercial success of multiscale hybrid composites is the addition of a functionality without greatly interfering with composite processability. Other mentioned issues are difficulties in CNP production upscaling and the cost-effective manufacturing of CNP/polymer composites. Even so, the future for multiscale composites with carbon nanofillers is promising, and more distinguishable characteristics and applications are certainly to come.

Acknowledgment The authors would like to express their gratitude to CNPq and CAPES/Brazil.

References [1] Hull D, Clyne TW. An introduction to composite materials. Cambridge: Cambridge University Press; 1996. [326 p]. [2] Talreja R. Polymer matrix composites. New York: Elsevier; 2001. [3] Irving PE, Soutis C. Polymer composites in the aerospace industry. Cambridge: Woodhead Publising & Elsevier; 2015. [536 p]. [4] Mallick PK, Composites FR. Materials, manufacturing and design. 3rd ed. New York: CRC Press; 2007. [638 p]. [5] Hollaway LC. The evolution of and the way forward for advanced polymer composites in the civil infrastructure. Construct Build Mater 2003;17(6–7):365–78. [6] Brondsted P, Lilholt H, Lystrup A. Composite materials for wind power turbine blades. Annu Rev Mat Res 2005;35:505–38. [7] Gorbatikh L, Wardle BL, Lomov SV. Hierarchical lightweight composite materials for structural applications. MRS Bull 2016;41(9):672–7.

464

Nanocarbon and its Composites

[8] Petsalas HJ, Andreopoulos AG. Treated aramid fibers as reinforcement in nonpolar matrices. J Appl Polym Sci 1989;38(4):593–604. [9] Thakur VK, Thakur MK, Pappu A. Hybrid polymer composite materials: properties and characterisation. Cambridge: Woodhead Publishing & Elsevier; 2017. [430 p]. [10] Zhang Q, Liu J, Sager R, Dai L, Baur J. Hierarchical composites of carbon nanotubes on carbon fiber: influence of growth condition on fiber tensile properties. Compos Sci Technol 2009;69(5):594–601. [11] Zhu J, Park SW, Joh H-I, Kim HC, Lee S. Preparation and characterization of isotropic pitch-based carbon fiber. Carbon Lett 2013;14(2):94–8. [12] Li H, Charpentier T, Du J, Vennam S. Composite reinforcement: recent development of continuous glass fibers. Int J Appl Glass Sci 2017;8(1):23–36. [13] Bhattacharyya D, Fakirov S. Synthetic polymer-polymer composites. Munich: Carl Hanser Verlag GmbH Co KG; 2012 [797 p]. [14] Van Der Zwaag S. Structure and properties of aramid fibres. In: Handbook of Textile Fibre Structure. Woodhead Publishing Limited; 2009. p. 394–412. [Chapter 13]. [15] Cziga´ny T. Trends in fiber reinforcements—the future belongs to basalt fiber. Express Polym Lett 2007;1(2):59. [16] Fiore V, Scalici T, Di Bella G, Valenza A. A review on basalt fibre and its composites. Compos Part B Eng 2015;74:74–94. [17] Dhand V, Mittal G, Rhee KY, Park SJ, Hui D. A short review on basalt fiber reinforced polymer composites. Compos Part B Eng 2015;73:166–80. [18] Kamar NT, Hossain MM, Khomenko A, Haq M, Drzal LT, Loos A. Interlaminar reinforcement of glass fiber/epoxy composites with graphene nanoplatelets. Compos Part A Appl Sci Manuf 2015;70:82–92. [19] Hadden CM, Klimek-Mcdonald DR, Pineda EJ, King JA, Reichanadter AM, Miskioglu I, et al. Mechanical properties of graphene nanoplatelet/carbon fiber/epoxy hybrid composites: multiscale modeling and experiments. Carbon 2015;95:100–12. [20] Khan SU, Kim JK. Improved interlaminar shear properties of multiscale carbon fiber composites with bucky paper interleaves made from carbon nanofibers. Carbon 2012;50(14):5265–77. [21] Hamada N, Sawada SL, Oshiyama A. New one-dimensional conductors: graphitic microtubules. Phys Rev Lett 1992;68(10):1579. [22] Mittal V, editor. Polymer nanotubes nanocomposites: synthesis, properties and applications. New Jersey: Wiley; 2010. [23] Xie XL, Mai YW, Zhou XP. Dispersion and alignment of carbon nanotubes in polymer matrix: a review. Mater Sci Eng R Rep 2005;49(4):89–112. [24] Khatiwada S, Armada CA, Barrera EV. Hypervelocity impact experiments on epoxy/ ultra-high molecular weight polyethylene fiber composites reinforced with single-walled carbon nanotubes. Procedia Eng 2013;58:4–10. [25] Dı´ez-Pascual AM. Hybrid carbon nanotube/fiber thermoplastic composites: mechanical, thermal, and electrical characterization. In: Hybrid polymer composites materials. 1st ed New York: Elsevier; 2017. p. 169–201. [Chapter 8]. [26] Amarasekera J. Conductive plastics for electrical and electronic applications. Reinf Plastic 2005;49:38–41. [27] Hattenhauer I, Tambosi PP, Duarte CA, Coelho LAF, Ramos A, Pezzin SH. Impact of electric field application during curing on epoxy-carbon nanotube nanocomposite electrical conductivity. J Inorg Organomet Polym Mater 2015;25(4):627–34. [28] Novoselov KS, Geim AK, Morozov SV, Jiang D, Zhang Y, Dubonos SV, et al. Electric field effect in atomically thin carbon films. Science 2004;22:666–9.

Multiscale hybrid composites with carbon-based nanofillers

465

[29] Geim AK, MacDonald AH. Graphene: exploring carbon flatland. Phys Today 2007;60 (8):35–41. [30] Soldano C, Mahmood A, Dujardin E. Production, properties and potential of graphene. Carbon 2010;48(8):2127–50. [31] Kim H, Abdala AA, Macosko CW. Graphene/polymer nanocomposites. Macromolecules 2010;43(16):6515–30. [32] Dresselhaus MS, Dresselhaus G, Eklund PC. Science of fullerenes and carbon nanotubes: their properties and applications. 1st ed. New York: Elsevier; 1996 [965 p]. [33] Kumar SK, Benicewicz BC, Vaia RA, Winey KI. 50th anniversary perspective: are polymer nanocomposites practical for applications? Macromolecules 2017;50(3):714–31. [34] Ajayan PM, Schadler IS, Braun PV. Nanocomposite science and technology. 1st ed. Weinheim: Wiley; 2004. [35] Sainsbury T, Erickson K, Okawa D, Zonte CS, Fr
echet JMJ, Zettl A. Kevlar functionalized carbon nanotubes for next-generation composites. Chem Mater 2010;22(6):2164–71. [36] Ma PC, Siddiqui NA, Marom G, Kim JK. Dispersion and functionalization of carbon nanotubes for polymer-based nanocomposites: a review. Compos Part A Appl Sci Manuf 2010;41(10):1345–67. [37] Wei J, Atif R, Vo T, Inam F. Graphene nanoplatelets in epoxy system: dispersion, reaggregation, and mechanical properties of nanocomposites. J Nanomater 2015;16 (1):374. [38] Tan SC, Kwok RWO, Chan JKW, Loh KP. Compression-induced graphite nanoplatelets orientation in fibre-reinforced plastic composites. Compos Part B Eng 2016;90:493–502. [39] Zhang X, Fan X, Yan C, Li H, Zhu Y, Li X, et al. Interfacial microstructure and properties of carbon fiber composites modified with graphene oxide. ACS Appl Mater Interfaces 2012;4(3):1543–52. [40] Warrier A, Godara A, Rochez O, Mezzo L, Luizi F, Gorbatikh L, et al. The effect of adding carbon nanotubes to glass/epoxy composites in the fibre sizing and/or the matrix. Compos Part A Appl Sci Manuf 2010;41(4):532–8. [41] Guo J, Lu C, An F, He S. Preparation and characterization of carbon nanotubes/carbon fiber hybrid material by ultrasonically assisted electrophoretic deposition. Mater Lett 2012;66(1):382–4. [42] Sager RJ, Klein PJ, Lagoudas DC, Zhang Q, Liu J, Dai L, et al. Effect of carbon nanotubes on the interfacial shear strength of T650 carbon fiber in an epoxy matrix. Compos Sci Technol 2009;69(7–8):898–904. [43] Rahmanian S, Thean KS, Suraya AR, Shazed MA, Mohd Salleh MA, Yusoff HM. Carbon and glass hierarchical fibers: Influence of carbon nanotubes on tensile, flexural and impact properties of short fiber reinforced composites. Mater Des 2013;43:10–6. [44] Liu Q, Li M, Gu Y, Zhang Y, Wang S, Li Q, et al. Highly aligned dense carbon nanotube sheets induced by multiple stretching and pressing. Nanoscale 2014;6(8): 4338–44. [45] Garcia EJ, Wardle BL, John Hart A. Joining prepreg composite interfaces with aligned carbon nanotubes. Compos Part A Appl Sci Manuf 2008;39(6):1065–70. [46] Wang S, Downes R, Young C, Haldane D, Hao A, Liang R, et al. Carbon Fiber/carbon nanotube buckypaper interply hybrid composites: manufacturing process and tensile properties. Adv Eng Mater 2015;17(10):1442–53. [47] Pan J, Li M, Wang S, Gu Y, Li Q, Zhang Z. Hybrid effect of carbon nanotube film and ultrathin carbon fiber prepreg composites. J Reinf Plast Comp 2017;36(6):452–63.

466

Nanocarbon and its Composites

[48] Ning H, Li J, Hu N, Yan C, Liu Y, Wu L, Liu F, Zhang J. Interlaminar mechanical properties of carbon fiber reinforced plastic laminates modified with graphene oxide interleaf. Carbon 2015;91:224–33. [49] Barber AH, Zhao Q, Wagner HD, Baillie CA. Characterization of E-glass–polypropylene interfaces using carbon nanotubes as strain sensors. Compos Sci Technol 2004;64(13): 1915–9. [50] M€ader E, Rausch J, Schmidt N. Commingled yarns–processing aspects and tailored surfaces of polypropylene/glass composites. Compos Part A Appl Sci Manuf 2008;39(4): 612–23. [51] Rausch J, M€ader E. Health monitoring in continuous glass fibre reinforced thermoplastics: manufacturing and application of interphase sensors based on carbon nanotubes. Compos Sci Technol 2010;70(11):1589–96. [52] Dı´ez-Pascual AM, Gonza´lez-Domı´nguez JM, Martı´nez MT, Go´mez-Fatou MA. Poly (ether ether ketone)-based hierarchical composites for tribological applications. Chem Eng J 2013;218:285–94. [53] Ashrafi B, Dı´ez-Pascual AM, Johnson L, Genest M, Hind S, Martinez-Rubi Y, et al. Processing and properties of PEEK/glass fiber laminates: effect of addition of singlewalled carbon nanotubes. Compos Part A Appl Sci Manuf 2012;43:1267–79. [54] Shen Z, Bateman S, Wu DY, McMahon P, Dell’Olio M, Gotama J. The effects of carbon nanotubes on mechanical and thermal properties of woven glass fibre reinforced polyamide-6 nanocomposites. Compos Sci Technol 2009;69(2):239–44. [55] Zhang JG. The effect of carbon fibers and carbon nanotubes on the mechanical properties of polyimide composites. Mech Compos Mater 2011;47(4):447. [56] Meszaros L, Gali IM, Czigany T, Czvikovszky T. Effect of nanotube content on mechanical properties of basalt fibre reinforced polyamide 6. Plastics Rubber Compos 2011; 40(6–7):289–93. [57] Rong RY, Li ZH, Li YX, Cai CL. Mechanical and tribological properties of polyimide composite reinforced with carbon fibers and carbon nanotube. Adv Mat Res 2011;311: 189–92. [58] Zhang L, Su D, Jin L, Li C. Polyamide 6 composites reinforced with glass fibers modified with electrostatically assembled multiwall carbon nanotubes. J Mater Sci 2012;47(14): 5446–54. [59] Zhang S, Liu WB, Hao LF, Jiao WC, Yang F, Wang RG. Preparation of carbon nanotube/ carbon fiber hybrid fiber by combining electrophoretic deposition and sizing process for enhancing interfacial strength in carbon fiber composites. Compos Sci Technol 2013;88:120–5. [60] Qian H, Bismarck A, Greenhalgh ES, Shaffer MS. Carbon nanotube grafted carbon fibres: a study of wetting and fibre fragmentation. Compos Part A Appl Sci Manuf 2010; 41(9):1107–14. [61] Suraya AR, Sharifah SMZ, Yunus R, Azowa IR. Growth of carbon nanotubes on carbon fibres and the tensile properties of resulting carbon fibre reinforced polypropylene composites. J Eng Sci Technol 2009;4(4):400–8. [62] Su C, Xue F, Li T, Xin Y, Wang M, Tang J, et al. Fabrication and multifunctional properties of polyimide based hierarchical composites with in situ grown carbon nanotubes. RSC Adv 2017;7(47):29686–96. [63] Gonzalez-Chi PI, Rodrı´guez-Uicab O, Martin-Barrera C, Uribe-Calderon J, Canch
eEscamilla G, Yazdani-Pedram M, et al. Influence of aramid fiber treatment and carbon nanotubes on the interfacial strength of polypropylene hierarchical composites. Compos Part B Eng 2017;122:16–22.

Multiscale hybrid composites with carbon-based nanofillers

467

[64] Li J, Bai T. The addition of polyethylene-polyamine surface treated carbon nanotube on the interfacial adhesion of carbon fiber-reinforced polyimide composite. Polym-Plast Technol Eng 2011;50(13):1393–7. [65] Yang X, Wang Z, Xu M, Zhao R, Liu X. Dramatic mechanical and thermal increments of thermoplastic composites by multi-scale synergetic reinforcement: carbon fiber and graphene nanoplatelet. Mater Des 2013;44:74–80. [66] Li F, Liu Y, Qu C, Xiao H, Hua Y, Sui G. Enhanced mechanical properties of short carbon fiber reinforced polyethersulfone composites by graphene oxide coating. Polymer 2015;59:155–65. [67] Luo W, Zhang B, Zou H, Liang M, Chen Y. Enhanced interfacial adhesion between polypropylene and carbon fiber by graphene oxide/polyethyleneimine coating. J Ind Eng Chem 2017;51:129–39. [68] Dı´ez-Pascual AM, Ashrafi B, Naffakh M, Gonza´lez-Domı´nguez JM, Johnston A, Simard B, et al. Influence of carbon nanotubes on the thermal, electrical and mechanical properties of poly (ether ether ketone)/glass fiber laminates. Carbon 2011;49(8):2817–33. [69] Kim SB, Nam BU, Park JS. Properties of polypropylene/carbon fiber/multiwalled carbon nanotube nanocomposites. 18th International Conference on Composite Materials; Aug 21–26; Korea; 2011. [70] Moll J, Kumar SK, Snijkers F, Vlassopoulos D, Rungta A, Benicewicz BC, et al. Dispersing grafted nanoparticle assemblies into polymer melts through flow fields. ACS Macro Lett 2013;2(12):1051–5. [71] Grzelczak M, Vermant J, Furst EM, Liz-Marza´n LM. Directed self-assembly of nanoparticles. ACS Nano 2010;4(7):3591–605. [72] Zhu J, Imam A, Crane R, Lozano K, Khabashesku VN, Barrera RV. Processing a glass fiber reinforced vinyl ester composite with nanotube enhancement of interlaminar shear strength. Compos Sci Technol 2007;67(7):1509–17. [73] Abot JL, Song Y, Schulz MJ, Shanov VN. Novel carbon nanotube array-reinforced laminated composite materials with higher interlaminar elastic properties. Compos Sci Technol 2008;68(13):2755–60. [74] Gnidakouong JRN, Roh HD, Kim JH, Park YB. In situ process monitoring of hierarchical micro
/nano-composites using percolated carbon nanotube networks. Compos Part A Appl Sci Manuf 2016;84:281–91. [75] Li Y, Zhang H, Peijs T, Bilotti E. Graphene delivery systems for hierarchical fiber reinforced composites. MRS Adv 2016;1(19):1339–44. [76] da Silva LV, Pezzin SH, Rezende MC, Amico SC. Glass Fiber/carbon nanotubes/epoxy three-component composites as radar absorbing materials. Polym Compos 2016;37(8): 2277–84. [77] Ku-Herrera JJ, May-Pat A, Avil
es F. An assessment of the role of fiber coating and suspending fluid on the deposition of carbon nanotubes onto glass fibers for multiscale composites. Adv Eng Mater 2016;18(6):963–71. [78] Bekyarova E, Thostenson ET, Yu A, Kim H, Gao J, Tang J, et al. Multiscale carbon nanotube—carbon fiber reinforcement for advanced epoxy composites. Langmuir 2007;23(7):3970–4. [79] Haghbin A, Liaghat G, Hadavinia H, Arabi AM, Pol MH. Enhancement of the electrical conductivity and interlaminar shear strength of CNT/GFRP hierarchical composite using an electrophoretic deposition technique. Materials 2017;10(10):1120. [80] Wang B, Zhou G, Wang L, Gao Y. Preparation and properties of hierarchical composites based on carbon nanotubes-coated glass fabric preform. Polym Compos 2016;37(4): 979–86.

468

Nanocarbon and its Composites

[81] Naito K. Tensile properties of polyimide composites incorporating carbon nanotubesgrafted and polyimide-coated carbon fibers. J Mater Eng Perform 2014;23(9):3245–56. [82] Tehrani M, Safdari M, Boroujeni AY, Razavi Z, Case SW, Dahmen K, et al. Hybrid carbon fiber/carbon nanotube composites for structural damping applications. Nanotechnology 2013;24(15)155704. [83] Zhou HW, Mishnaevsky L, Yi HY, Liu YQ, Hu X, Warrier A, et al. Carbon fiber/carbon nanotube reinforced hierarchical composites: effect of CNT distribution on shearing strength. Compos Part B Eng 2016;88:201–11. [84] Dı´ez-Pascual AM, Naffakh M, Marco C, Go´mez-Fatou MA, Ellis GJ. Multiscale fiberreinforced thermoplastic composites incorporating carbon nanotubes: a review. Curr Opin Solid State Mater Sci 2014;18(2):62–80. [85] Pedrazzoli D, Pegoretti A. Expanded graphite nanoplatelets as coupling agents in glass fiber reinforced polypropylene composites. Compos Part A Appl Sci Manuf 2014;66: 25–34. [86] Veedu VP, Cao A, Li X, Ma K, Soldano C, Kar S, et al. Multifunctional composites using reinforced laminae with carbon-nanotube forests. Nat Mater 2006;5(6):457–62. [87] Ogasawara T, Ishida Y, Kasai T. Mechanical properties of carbon fiber/fullerenedispersed epoxy composites. Compos Sci Technol 2009;69(11
12):2002–7. [88] Godara A, Mezzo L, Luizi F, Warrier A, Lomov SV, van VAW, et al. Influence of carbon nanotube reinforcement on the processing and the mechanical behaviour of carbon fiber/ epoxy composites. Carbon 2009;47(12):2914–23. [89] Tang Y, Ye L, Zhang Z, Friedrich K. Interlaminar fracture toughness and CAI strength of fibre-reinforced composites with nanoparticles—a review. Compos Sci Technol 2013;86:26–37. [90] Grimmer CS, Dharan CKH. Enhancement of delamination fatigue resistance in carbon nanotube reinforced glass fiber/polymer composites. Compos Sci Technol 2010;70(6): 901–8. [91] Li Y-L, Shen M-Y, Chen W-J, Chiang C-L, Yip M-C. Tensile creep study and mechanical properties of carbon fiber nano-composites. J Polym Res 2012;19(7):9893. [92] Siegfried M, Tola C, Claes M, Lomov SV, Verpoest L, Gorbatikh L. Impact and residual after impact properties of carbon fiber/epoxy composites modified with carbon nanotubes. Compos Struct 2014;111(1):488–96. [93] Taraghi I, Fereidoon A, Taheri-Behrooz F. Low-velocity impact response of woven Kevlar/epoxy laminated composites reinforced with multi-walled carbon nanotubes at ambient and low temperatures. Mater Des 2014;53:152–8. [94] Zhou X, Shin E, Wang KW, Bakis CE. Interfacial damping characteristics of carbon nanotube-based composites. Compos Sci Technol 2004;64(15 SPEC. ISS):2425–37. [95] Li B, Olson E, Perugini A, Zhong WH. Simultaneous enhancements in damping and static dissipation capability of polyetherimide composites with organosilane surface modified graphene nanoplatelets. Polymer 2011;52(24):5606–14. [96] Manero A, Gibson J, Freihofer G, Gou J, Raghavan S. Evaluating the effect of nanoparticle additives in Kevlar® 29 impact resistant composites. Compos Sci Technol 2015;116:41–9. [97] Micheli D, Vricella A, Pastore R, Delfini A, Giusti A, Albano M, et al. Ballistic and electromagnetic shielding behaviour of multifunctional Kevlar fiber reinforced epoxy composites modified by carbon nanotubes. Carbon 2016;104:141–56. [98] Grujicic M, Bell WC, Thompson LL, Koudela KL, Cheeseman BA. Ballistic-protection performance of carbon-nanotube-doped poly-vinyl-ester-epoxy matrix composite armor reinforced with E-glass fiber mats. Mater Sci Eng A 2008;479(1–2):10–22.

Multiscale hybrid composites with carbon-based nanofillers

469

[99] Qian H, Greenhalgh ES, Shaffer MSP, Bismarck A. Carbon nanotube-based hierarchical composites: a review. J Mater Chem 2010;20(23):4751–62. [100] Wang S, Qiu J. Enhancing thermal conductivity of glass fiber/polymer composites through carbon nanotubes incorporation. Compos Part B Eng 2010;41(7):533–6. [101] Noh YJ, Kim SY. Synergistic improvement of thermal conductivity in polymer composites filled with pitch based carbon fiber and graphene nanoplatelets. Polym Test 2015;45:132–8. [102] Qiu J, Zhang C, Wang B, Liang R. Carbon nanotube integrated multifunctional multiscale composites. Nanotechnology 2007;18(27)275708. [103] Wichmann MHG, Sumfleth J, Gojny FH, Quaresimin M, Fiedler B, Schulte K. Glass-fibrereinforced composites with enhanced mechanical and electrical properties—benefits and limitations of a nanoparticle modified matrix. Eng Fract Mech 2006;73(16):2346–59. [104] Vilatela JJ, Eder D. Nanocarbon composites and hybrids in sustainability: a review. ChemSusChem 2012;5(3):456–78. [105] Gojny FH, Wichmann MHG, Fiedler B, Bauhofer W, Schulte K. Influence of nanomodification on the mechanical and electrical properties of conventional fibre-reinforced composites. Compos Part A Appl Sci Manuf 2005;36(11):1525–35. [106] Qin W, Vautard F, Drzal LT, Yu J. Mechanical and electrical properties of carbon fiber composites with incorporation of graphene nanoplatelets at the fiber-matrix interphase. Compos Part B Eng 2015;69:335–41. [107] Drubetski M, Siegmann A, Narkis M. Electrical properties of hybrid carbon black/carbon fiber polypropylene composites. J Mater Sci 2007;42(1):1–8. [108] Markov A, Fiedler B, Schulte K. Electrical conductivity of carbon black/fibres filled glass-fibre-reinforced thermoplastic composites. Compos Part A Appl Sci Manuf 2006;37(9):1390–5. [109] Shen L, Wang FQ, Yang H, Meng QR. The combined effects of carbon black and carbon fiber on the electrical properties of composites based on polyethylene or polyethylene/ polypropylene blend. Polym Test 2011;30(4):442–8. [110] B€oger L, Wichmann MHG, Meyer LO, Schulte K. Load and health monitoring in glass fibre reinforced. Composites with an electrically conductive nanocomposite epoxy matrix. Compos Sci Technol 2008;68(7–8):1886–94. [111] Sebastian J, Schehl N, Bouchard M, Boehle M, Li L, Lagounov A. Health monitoring of structural composites with embedded carbon nanotube coated glass fiber sensors. Carbon 2014;66:191–200. [112] Xu X, Zhang Y, Jiang J, Wang H, Zhao X, Li Q, et al. In-situ curing of glass fiber reinforced polymer composites via resistive heating of carbon nanotube films. Compos Sci Technol 2017;149:20–7. [113] Nguyen N, Hao A, Park JG, Liang R. In situ curing and out-of-autoclave of interply carbon fiber/carbon nanotube buckypaper hybrid composites using electrical current. Adv Eng Mater 2016;18(11):1906–12. [114] Gonza´lez C, Vilatela JJ, Molina-Aldareguı´a JM, Lopes CS, LLorca J. Structural composites for multifunctional applications: current challenges and future trends. Prog Mater Sci 2017;89:194–251. [115] Islam MS, Deng Y, Tong L, Faisal SN, Roy AK, Minett AI, et al. Grafting carbon nanotubes directly onto carbon fibers for superior mechanical stability: towards next generation aerospace composites and energy storage applications. Carbon 2016;96:701–10. [116] Xiong C, Li T, Zhao T, Dang A, Li H, Ji X, Jin W, Jiao S, Shang Y, Zhang Y. Reduced graphene oxide-carbon nanotube grown on carbon fiber as binder-free electrode for flexible high-performance fiber supercapacitors. Compos Part B Eng 2017;116:7–15.

470

Nanocarbon and its Composites

[117] Kwon YJ, Kim Y, Jeon H, Cho S, Lee W, Lee JU. Graphene/carbon nanotube hybrid as a multi-functional interfacial reinforcement for carbon fiber-reinforced composites. Compos Part B Eng 2017;122:23–30. [118] Gao B, Zhang R, He M, Sun L, Wang C, Liu L, et al. Effect of a multiscale reinforcement by carbon fiber surface treatment with graphene oxide/carbon nanotubes on the mechanical properties of reinforced carbon/carbon composites. Compos Part A Appl Sci Manuf 2016;90:433–40. [119] Bystrzejewska-Piotrowska G, Golimowski J, Urban P. Nanoparticles: their potential toxicity, waste and enviromental management. Waste Manag 2009;29(9):2587–95.