Figure - available via license: Creative Commons Attribution 3.0 Unported
Content may be subject to copyright.
Source publication
Carbon/carbon composites (C/C composites) possess superior characteristics of low density, high strength, extremely low coefficient of thermal expansion, and high fatigue resistance. In carbonization process, the high-temperature pyrolysis made of carbon, hydrogen, oxygen, and other elements results in a lot of voids and cavities generated in the i...
Contexts in source publication
Context 1
... the following treatments including carbonization, reimpregnation, and graphitization must be done to manufacture C/C composite finally. The entire man- ufacturing process of C/C composite is shown in Figure 1, and all of manufacturing treatments are described as follows. ...Context 2
... and CNTs can increase the interfacial friction between carbon fiber and matrix to enhance the interlaminar shearing strength. But the shearing strength started to decrease as CNTs content increases up to 1.5 wt% because agglomeration attributed to much CNTs content seems to be impure to result in the stress concentration which causes crevice shown in Figure 10. Hence, the interlaminar shearing strength decreases. ...Context 3
... Energy Analysis. From the results shown in Figure 11 and Table 4, the impacting energy does not apparently increase whether CNTs were added into matrix or not. Because the failure mode of impact test is the fiber breakage dominated by fiber, CNTs do not notably influence on resistance to impact whether CNTs were added into matrix or not. ...Similar publications
This study addresses the challenge of designing simple and environmentally friendly methods for the preparation of effective electromagnetic wave (EMW) absorbing materials with tailored microstructures and multi‐component regulation. N, O doped walnut‐like porous carbon composite microspheres loaded with FeCo nanoparticles (WPCM/Fe–Co) are synthesi...
Interlaminar shear strength is an important characteristic of the characteristics of composite structures. This article presents the results of an experimental study of the role of carbon nanotube reinforcement of a fibrous filler of carbon fabrics in increasing the interlayer shear strength of composite articles made of carbon fiber reinforced pla...
Bimetal/carbon aerogels have many advantages, such as nano-scale properties, low density, large specific surface area, and high porosity, but their application in dye-sensitized solar cells (DSSCs) as a counter electrode (CE) instead of noble metal Pt is relatively rare. In this paper, a low-cost sodium alginate was used to obtain a Co-Mo bimetal/c...
Ultra-low-density graphene nanosheet (GNS)/carbon composite aerogels (CAs) were prepared via GO (graphene oxide)/RF (resorcinol–formaldehyde) aerogel composite, supercritical fluid drying, and carbonization. Graphene oxide was found to act as an efficient anti-shrinkage additive in the carbonization process, making the linear shrinkage ratios decre...
To address the brittle compounds formation issue in the brazed seam, an innovative 3-dimensional (3D) graphene sponge (GS) was selected to integrate with a single AgCuTi braze, forming a composite braze filler to achieve an AgCu eutectic dominated brazed seam with almost no brittle compounds. Interfacial microstructure of the C/C-C/C (C/C: carbon f...
Citations
... This reduction can be explained using the same technique used to polymer-CNT composites. The literature on CNT-polymer composites indicates that exceeding a specific CNT dosage results in inadequate dispersion of CNT within the polymer matrix, consequently diminishing its mechanical properties due to the excessively high aspect ratio and surface area [68,69]. A study established that inadequate dispersion of CNTs results in a significant decrease in the aspect ratio of reinforcement, causing unbonded CNTs to slide over one another [70]. ...
... This may lead to a decline in the mechanical properties of the composite. Likewise, [68] found that the agglomeration of CNT within the polymer matrix effectively reduces the contact area between the CNT and the matrix, hence diminishing the resistance to mechanical loading. Therefore, the same mechanism of effect of CNT agglomeration could be applied to NC-bitumen composite to elucidate the possible cause for the reduction in G* value when NC content rises beyond 6%. ...
Functional and rheological characteristics are two essential criteria for the success of any modifiers for the modification of bitumen. Recently, nanoclay has grabbed extensive attention as a key solution for enhancing the performance of bitumen. This study focuses on evaluating the dispersion, storage stability, high-temperature performance, and aging resistance potential properties of bitumen VG-30 modified with montmorillonite bentonite hydrophilic nanoclay (NC). Various proportions (0, 2, 4, 6, and 8% by weight of bitumen) of NC were blended with VG-30 using a high shear mixer (HSM). Various performance assessments, including kinematic viscosity by Brookfield Rotational Viscometer (BRV), multiple stress creep recovery (MSCR), high-temperature performance grade (PG), frequency sweep along with scanning electron microscopy (SEM) were conducted. SEM images and viscosity data analysis show that dispersion problem arises beyond 6% of NC addition while phase separation is in the acceptable range. Further, considerable increment in Superpave rutting parameter (G*/Sinδ) and recovery percentage (%R), and decrease in non-recoverable compliance (Jnr) was seen, resulted up to 30% improvement in rutting performance of the bitumen. Furthermore, the potential for aging resistivity resulted a significant drop in aging index (AI) values, suggesting that introducing NC to bitumen could significantly improve aging resistivity. Moreover, rheological approaches can be helpful to understand temperatures and frequency dependent aging behaviours of bitumen.
... Further studies on the effect of agglomeration of CNTs, stacking-up, and rolling-up of graphene sheets on elastic properties of nano-composites (CNT/polystyrene and graphene sheet/polystyrene composites are developed by Mori-Tanaka micromechanics method [25] and observed the reduction of stiffness with the effects mentioned above. Li et al [26] calculated the properties of Amino-functional multi-walled carbon nano-tubes added epoxy using the Halpin-Tsai model for CFRP composites. They concluded that the addition of CNT has improved flexural strength. ...
Composite materials are the largely used engineering materials in aerospace and automobile industries due to their high specific strength and high specific stiffness. The properties of the composites are very much important to design and develop the machine parts. They vary with fiber content, fiber properties, matrix properties, and type of manufacturing process. Number of experiments are required to obtain the properties and the best combination of fibers and matrices. However, several analytical methods are available to find the properties of the composite to avoid the number of experiments. In the present study, the properties of CFRP, GFRP, Amino-functional multi-walled carbon nanotubes (CNT) added CFRP, CNT added GFRP composites have been calculated by using the properties of fiber, interphase between fiber and matrix, matrix, and CNT. The properties of CNT added epoxy are obtained using Halpin-Tsai equation in first stage, and in the second stage, the properties of interphase are calculated using the properties of CNT added epoxy and fiber properties. The third stage, the properties of CFRP and GFRP are calculated using three phase constitutive model by considering the properties of fiber, interphase, and CNT added matrix. The properties are calculated at fiber diameters: 8 μm and 14 μm while varying the fiber volume fraction (%): 0 to 70%, interphase thickness: 50 nm to 500 nm, weight fraction of CNT (%) added in epoxy: 0 to 5%. The addition of CNT has improved the elastic properties of CFRP and GFRP. The elastic properties of the composites are improved significantly with increase in the interphase thickness.
... Recently, several studies have been reported in the literature related to the fabrication of CNTs reinforced CCCs (CNT-CCCs) mainly focuses on the methods of CNTs incorporation, their effects on microstructures, density, tribological characteristics, compressive, flexural, and interlaminar shear strength of the CCCs. [32][33][34][35][36][37][38] However, no study has been found related to the effect of CNTs on other important properties of the phenolic resinbased CCCs like tensile properties, viscoelastic properties, electrical conductivity, and thermal stability which are the crucial parameters for the evaluation of the performance of the composites used for highperformance structural applications. ...
In this research work, Carbon-carbon composites (CCCs) were fabricated via carbonization of carbon nanotubes (CNTs)-coated carbon textile (CNT-CF) reinforced polymer matrix composites (PMCs) preforms at 600, 900, 1200, and 1500 C in a tubular furnace. To obtain CNT-CF, MWCNTs were produced radially on the surface of the nano-nickel particles plated carbon textile at 700 C using catalytic chemical vapor deposition method and C 2 H 2 gas as a carbon source. The effects of CNT coating on carbon textiles were evaluated using FESEM, HR-TEM, XRD, Raman, TGA, and BET analysis. The effects of heat treatment temperatures on CNTs coated and uncoated PMCs manufactured using simple hand-layup method subsequently hot compressing were evaluated through XRD, FESEM, density, electrical conductivity measurement, tensile and flexural test, and viscoelastic properties using DMTA. The CNT coated CCCs obtained at 1500 C exhibited $ 66, 62, 83, 27, 44, 30, and 36% enhancement in electrical conductivity, storage modulus, loss modulus, tensile strength, Young's modulus, flexural strength, and flexural modulus of CNT coated CCCs, respectively compare to uncoated CCCs. Moreover, substantial enhancement in thermal stability of PMCs and CCCs make CNT-CF as one of the competent alternate reinforcement for the fabrication of structural parts used in high-performance applications.
... This leads to a decrease in the effective contact area between nano Al 2 O 3 and polymer matrix which decreases the resistance to mechanical loading and therefore reducing the permanent deformation performance characteristics. Reduction in resistance against mechanical loading due to the agglomeration effect has also been reported by Li et al. [75]. The strength of the nanocomposite modified asphalt binder may be attributed to the fact that nanomaterials tend to form a more stable structure with SBS polymer, this new structure can absorb and transfer the load from the asphalt binder matrix to the nanocomposite matrix and therefore helps in improving the rutting resistance [76]. ...
The present study investigates the effect of using nano Al2O3 as a modifier for SBS modified asphalt binders. The effects of varying concentrations (1%, 2%, 3%, 4% and 5%) of nano Al2O3 on SBS modified asphalt binder were evaluated by utilizing various physical tests like penetration, softening point, elastic recovery, and penetration index test. Rheological investigations were carried out by performing frequency sweep tests. Rutting and fatigue performance of the modified asphalt binders was evaluated by using the Superpave rutting parameter, multiple stress creep and recovery test, Superpave fatigue parameter, and linear amplitude sweep tests. Furthermore, the storage stability of the modified asphalt binders was evaluated and the separation index was calculated. The aging resistance was evaluated by using the aging index based on the Superpave rutting parameter. Results showed that the addition of nano Al2O3 has a positive effect on the rutting and fatigue performance of SBS modified asphalt binders. Storage stability of the SBS modified asphalt binders improved significantly after the addition of nano Al2O3, and the aging resistance of the asphalt binders also improved.
... However, with an increase in CNT content from 1.5% to 2.25%, a slight decrease in creep stiffness is evident. The literature on CNT-polymer composite further explains that the addition of CNT above a certain dose can reduce the mechanical strength because of poor dispersion (Manchado et al. 2005;Ma et al. 2007Ma et al. , 2008Li et al. 2012). Li et al. (2012) concluded that the agglomeration of CNT results in an effective reduction of the contact area between polymer and CNT. ...
... The literature on CNT-polymer composite further explains that the addition of CNT above a certain dose can reduce the mechanical strength because of poor dispersion (Manchado et al. 2005;Ma et al. 2007Ma et al. , 2008Li et al. 2012). Li et al. (2012) concluded that the agglomeration of CNT results in an effective reduction of the contact area between polymer and CNT. As a result, the efficiency of load transfer from polymer to CNT phase in CNT-polymer composite gets reduced. ...
Although many research works are available on evaluating the effect of carbon nanotube (CNT) on intermediate and high temperature performance of asphalt binder, limited studies have been reported for its effect on low temperature properties. Moreover, reported research work showed inconsistent conclusive remarks about its influence on the low temperature properties of asphalt binder. Therefore, along with the conventionally adopted technique, this study aimed at investigating the effect of CNT on low temperature properties of asphalt binder using the dissipated energy-based approach to make an appropriate conclusive remark. CNT content was varied as 0%, 0.75%, 1.5%, and 2.25% by the weight of asphalt binder. Initially, creep stiffness and creep rate corresponding to 60 s creep period were evaluated. Although CNT addition changed the creep stiffness and creep rate, the impact was not statistically significant at 0.75% CNT. However, a subsequently higher dose of 1.5% CNT significantly increased the creep stiffness and decreased the creep rate. A master curve for creep stiffness, relaxation modulus, creep stiffness rate, and creep relaxation rate was drawn to understand the effect of prolonged creep period on low temperature properties. The detrimental effect of CNT on low temperature properties of asphalt binder was found to be apparent, especially in a higher creep period zone. Subsequently, viscoelastic modeling of creep compliance data obtained from a bending beam rheometer (BBR) test was carried out using the Burgers model. Different energy components (stored and dissipative) were subsequently evaluated based on model parameters. Stored, as well as dissipated energy components, were found to be decreasing with an increase in CNT content to 1.5%. However, the degree of decrease in the dissipated energy component was found to be relatively higher compared to the corresponding decrease in the stored energy component. As a result, the dissipated energy ratio (DER), which is expected to be higher for better low temperature performance, was found to be decreasing with the incremental dosages of CNT. Although CNT addition decreased the DER value, the impact was not statistically significant at 0.75% CNT. However, a subsequently higher dose of 1.5% CNT showed a significant decrease in DER value. Such a response further reinforced that CNT addition may have a negative impact on low temperature properties of asphalt binder.
... Where refers to the volume fraction of agglomerations zone which is related to the overall CNTs fraction by = , being the CNT concentration in of a cluster. Li et al. [99] obtained the same effect for CNT-reinforced carbon/carbon composites. As CNTs content increases up to 1.2 wt%, inter-laminar shearing strength increases by 30%. ...
Carbon nano tubes (CNTs), comprising one dimensional (1D) carbon tubes that
significantly strengthen the base matrix when added as a reinforcement element. It is light in weight
and very low weight fractions (vol% or wt%) of well-dispersed CNTs enhance mechanical properties
effectively. Due to its poor wettability during liquid mixing, CNTs reinforced composites are mostly
prepared by solid-state processing, extrusion, hot pressing, etc. after premixing of the matrix and
CNTs powders in nano size. Irrespective of the production routes, matrices, and chemical treatments,
CNTs agglomerate within the matrix structure. That leads to dispersion problem of CNTs in matrix
materials and weaken the properties of the composites. CNTs produce small clusters/agglomerates
due to their high affinity and affect the texture of grain boundaries. This review discusses the effect
of CNTs agglomerations in composites formation for various CNTs reinforced composites. The study
covers the effect of vol%, wt%, and dispersion medium for reinforcement.
... Where refers to the volume fraction of agglomerations zone which is related to the overall CNTs fraction by , being the CNT concentration in of a cluster. Li et al. [99] obtained the same effect for CNT-reinforced carbon/carbon composites. As CNTs content increases up to 1.2 wt%, inter-laminar shearing strength increases by 30%. ...
... Further, it is also to be noted that the addition of CNT beyond a certain amount may not be advisable for asphalt binder modification purpose due to the problem of poor dispersion. Literature, especially on mechanical properties of CNT-polymer nanocomposite shows that addition of CNT content above a certain dose may lead to reduction in its mechanical property due to poor dispersion of CNT in the polymer matrix (Du, Bai, & Cheng, 2007;Li, Shen, Su, Chiang, & Yip, 2012;Ma, Kim, & Tang, 2007;Ma, Tang, & Kim, 2008a;Manchado et al., 2005). Salvetat et al. (1999) explained that poor dispersion of CNT results into effective reduction in aspect ratio of CNT reinforcement. ...
... As a result, it may cause slipping of CNTs (whichever are not bonded to polymer matrix) over each other, resulting in a reduction in the mechanical property of composite. Similarly, Li et al. (2012) explain that agglomeration problem leads to an effective reduction in the area of contact between CNT and polymer matrix which may result in a decrease in effective resistance to mechanical loading. Therefore, a similar mechanism may be applied to asphalt binder-CNT composite to explain the possible cause for the reduction in stiffness value at higher CNT dosages. ...
This article aimed at providing comprehensive information on the use of nanomaterial in asphalt binder and mixes based on an exhaustive review of the literature. The complete literature review can broadly be perceived into three different segments. The first segment of this review discusses (a) the need of nanomaterial, and (b) different types of nanomaterials with their respective characteristics. The second segment of this review work discusses about the various functional aspects which have been reported to have an important role on or before construction of asphaltic layer, i.e. (a) mixing of nanomaterials with asphalt binder, (b) nanomaterial dispersion into asphalt binder matrix, and (c) high-temperature storage stability of binary composite (asphalt binder and nanomaterial) and triple composite (asphalt binder, polymer additive and nanomaterial) under high-temperature condition. Among different types of mixing approach, use of a high shear mixer and ultra-sonication individually or in combination has been reported in the literature for an efficient way for dispersion of nanomaterial in an asphalt binder matrix. To evaluate mixing of nanomaterial in asphalt binder matrix, different microscopic approach such as X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM) has been recommended in the literature. The third segment emphasises on the effect of nanomaterial addition on performance-based parameters for (a) aging resistivity potential, (b) moisture damage resistivity potential, (c) intermediate, (d) high, and (e) low-temperature performance. The review of the literature showed that the addition of nanomaterial to asphalt binder not only improves the aging resistivity potential of asphalt binder but also improves the moisture damage resistivity potential, high, and intermediate temperature performance of asphalt binder and mixes. However, the mixed response was observed from the review of literature for the corresponding effect of nanomaterial on low-temperature performance parameters.
... More recently, Dae et al. have found that the carbon nanotubes (CNTs) can be used to improve the tribological properties of CCs [22]. CNTs can also be used to enhance density and mechanical strength of the CCs [23,24]. Nanographene platelets exhibit low viscosity in its polymer composites and also have high heat of curing, hence it can be a good filler for crack filling and densification of the CCs [25]. ...
... A comparison is also carried out of flexural strength and electrical conductivity of CCs obtained from present study with the best reported values in the open literature of CCs filled with different fillers like, carbon black [15], MCMBs [16], graphite powder [18] and CNTs [23], carbonized at 900-1000°C as shown in Table 1. It can be seen that HHC filled CCs exhibit higher flexural strength, and electrical conductivity than MCMBs, however carbon black and CNTs show higher flexural strength than HHC fillers. ...
... Carbon black [15] MCMBs [16] Graphite powder [18] CNTs [23] HHC (present study) ...
In the present study, human hair derived carbon powder (HHC) synthesized in home laboratory is characterized via SEM, AFM, FT-IR, XRD, Raman, XPS, and TGA. Then HHC is used as a low cost reinforcing filler at 0–50 wt% with phenolic resin for fabricating carbon fabric reinforced polymer composites (CPCs) and its carbon-carbon composites (CCs). CPCs are fabricated via simple hand-lay techniques for resin-HHC slurry impregnation followed by hot pressing while CCs are obtained by carbonization of CPCs at 600 and 900 °C. Effects of HHC loading on CPCs and CCs are evaluated through static and dynamic mechanical thermal analysis, density, electrical conductivity, morphology, and microstructure studies. Tensile and flexural properties (strength and modulus) of CPCs and CCs improve significantly (∼25 to 73%) at 30 wt% HHC loading. Storage modulus (E′) and loss modulus (E″) of CPCs increase up to 132 and 104%, respectively with addition of HHC up to 40 wt%. E′ and E″ of unfilled CCs increase with carbonization temperature, however they decrease with increasing HHC content. In addition to high specific properties, CCs also exhibit substantial increment (∼233%) in electrical conductivity and thermal stability, which make HHC one of the most suitable material for high temperature-structural applications.
... Such a decrease can be again explained on the same principle as applied for polymer-CNT composite. The literature on CNT-polymer composite shows that the addition of CNT content above a certain dose will result into poor dispersion of CNT in the polymer matrix, leading to a reduction in its mechanical property due to very high aspect ratio and surface area ( Manchado et al. 2005;Du et al. 2007;Ma et al. 2007Ma et al. , 2008Li et al. 2012). Salvetat et al. (1999) demonstrated that poor dispersion of CNT leads to effective reduction in the aspect ratio of reinforcement, which results in slipping of CNTs (whichever are not bonded to the polymer matrix) over each other. ...
... This may result in the reduction in the mechanical property of the composite. Similarly, Li et al. (2012) concludes that agglomeration of CNT in the polymer matrix results in effective reduction on the contact area between the CNT and matrix, leading to decreasing the effect of resistance to mechanical loading. Hence, the same mechanism of effect of CNT agglomeration could be applied to CNT-asphalt binder composite to explain the possible reason for the decrease in G Ã value when CNT content increased from 1.5 to 2.25%. ...
The present research work was undertaken to evaluate the rutting performance of carbon nanotube (CNT)–modified asphalt binders. Additionally, intermediate-temperature performance, aging resistivity potential, and high-temperature storage stability were also evaluated. Reported literature on rutting performance of CNT-modified asphalt binders is mainly based on the Superpave rutting parameter (G*/sinδ), which does not account for the recovery aspect of binder. The paper first highlights the importance of the elastic response of CNT-modified asphalt binders for better understanding about its rutting performance. Further, different approaches such as the evaluation of zero shear viscosity (ZSV), creep test, and multiple stress creep recovery (MSCR) were utilized to reach appropriate conclusions. A recently developed approach, linear amplitude sweep (LAS), was used for evaluating intermediate-temperature performance. The CNT was varied as 0, 0.4, 0.75, 1.5, and 2.25% by the weight of control binder. The G*/sinδ value was found to increase until 1.5% CNT content; however, the addition of 2.25% CNT resulted in decreased G*/sinδ, indicating reduced rutting performance at higher CNT content. Contrary to the G*/sinδ trend, significant improvement in recovery value was observed for all CNT percentages. Further, based on detailed analysis carried out for different rheological parameters such as ZSV value (evaluated using the steady shear approach), deformation resistivity potential from creep test, recovery (R), and nonrecoverable creep compliance (Jnr) from the MSCR test, CNT addition to the control binder showed significant improvement in rutting resistivity potential for all CNT percentages. Although ZSV value significantly improved with the addition of CNT, the increase in CNT content showed an early transition from Newtonian to non-Newtonian behavior. Further, analysis for stress sensitivity was carried based on the R and Jnr values obtained from the MSCR test, which showed an increase in stress sensitivity with the addition of CNT to the control binder. The need for improvement in the current protocol used for evaluating stress sensitivity of asphalt binder (based on the MSCR test) has also been discussed. Improvement in intermediate-temperature performance evaluated through LAS test was also observed. Also, CNT addition to asphalt binder was found to be stable under high-temperature storage conditions. Overall, improvement in high- and intermediate-temperature performance can be expected with the addition of CNT to the control binder.