S-parameters,electrical permittivity,and absorbing energy measurements of carbon nanotubes-based composites in X-band

Composites based on carbon nanotubes (CNT) have recently received great attention as a possible new generation of radar absorbing materials (RAM), due to their efficient microwave attenuation capacity and low density. However, RAM performance can vary significantly depending on the CNT being used. Aiming to directly show the influence of CNT from two different suppliers, both multi-walled and non-functionalized (CNT-B and CNT-K), the electromagnetic behaviors of RAM processed in epoxy resin are compared. Scattering parameters (S-parameters), complex electrical permittivity and magnetic permeability, and absorbed energy of the composites in the X-band (8.2–12.4 GHz) are evaluated. The results clearly show the influence of the two different CNT on the electromagnetic characteristics of composites. CNT-B based composites behave as broadband RAM with the tendency of better attenuation results above 12.4 GHz. On the other hand, CNT-K based composites show good attenuation results in the X-band (>99%). Undoubtedly, the results confirm that the longer length of CNT-K favored the interconnection among the filaments, as well as, the formation of compact agglomerates surrounded by resin rich regions, which favored the impedance matching and mechanisms of losses in the processed RAM.     

Effect of carbon nanotube dispersion on the complex permittivity and absorption of nanocomposites in 2–18 GHz ranges

The effect of dispersion processes on complex permittivity and microwave absorption in 2?18 GHz ranges is presented for nanocomposites loaded with different amounts of carbon nanotubes (CNTs) ranging from 1 to 5 wt %. The ultrasonic sonication (US) method and the three‐roll mill (TRM) method were performed for the manufacturing of the CNT/epoxy absorbers with different dispersing levels. Microscopic observations revealed that the CNT agglomerates were reduced after the TRM process, and individual CNTs were uniformly dispersed in the epoxy resin. For the same weight content of CNT fillers, the percentage increase of between US and TRM samples varies from 35.5% to 101.7% while the corresponding increment of (dielectric loss) varies from 79.6% to 248.8%. A minimum reflection loss for the US sample with 2 wt % CNTs is only ?7.8 dB at 11.3 GHz while the corresponding TRM sample is greatly improved to reach ?37.4 dB at 7.76 GHz for the same matching thickness of 3 mm. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40963.     

Effect of crosslink density on thermal conductivity of epoxy/carbon nanotube nanocomposites

The effect of the polymeric crosslink density on the thermal conductivity of an epoxy nanocomposite was investigated by adding two different diamine‐functionalized multiwalled carbon nanotubes (diamine‐MWNTs) to the epoxy resin as co‐curing agents and conducting fillers. Tetramethylenediamine (TMDA)‐MWNTs resulted in an epoxy nanocomposite with a higher crosslink density than octamethylenediamine (OMDA)‐MWNTs. Interestingly, epoxy/TMDA‐MWNT nanocomposites under 1.5 wt % nanotube concentration, showed a higher thermal conductivity than an epoxy/OMDA‐MWNT nanocomposite with the same concentration of nanotubes. In contrast, for higher diamine‐MWNT concentrations (over 2.0 wt %), the thermal conductivity of the epoxy/OMDA‐MWNT nanocomposite was higher than that with TMDA‐MWNTs. We observed that for low MWNT concentrations, where a percolating network was not formed, a high crosslink density enhanced the thermal conductivity via phonon transport. However, for high MWNT concentrations, a high crosslink density hinders the formation of a percolating network and lowers the thermal conductivity. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44253.     

Morphological,mechanical, and electromagnetic interference shielding effectiveness characteristics of glass fiber/epoxy resin/MWCNT buckypaper composites

Glass fiber/epoxy resin composites (GF/EP) using one and three multi-walled carbon nanotube buckypapers (BP) were obtained and their complex parameters, reflectivity, and electromagnetic interference (EMI) shielding effectiveness (SE) at X-band (8.2–12.4 GHz) and Ku-band (12.4–18 GHz) were evaluated. The preparation of BP used polyacrylonitrile (PAN) nanofibers (PF These composites show both large storage and energy loss capacity in both bands revealing promising results related to EMI SE applications. Besides, a high attenuation of around 67% and 72% were achieved for BP based composites. The cross-section view of the buckypaper and the laminates was analyzed by scanning electron microscopy (SEM). The incorporation of the CNT film into the laminates showed no improvements in the elastic properties through dynamic mechanical analyses (DMA). Nevertheless, a decrease in the shear properties by the compression shear test (CST) and interlaminar shear strength (ILSS) has been observed. GF/EP/BP/PF composite presented a reduction of 29 and 39% in its ILSS properties compared to the base laminate (GF/EP). Also, the decrease was even more significant, revealing a steep reduction in its CST properties. On the other hand, the removal of the pan nanofiber (PF) led to better mechanical properties for GF/EP/BP/RPF composites. Results have shown ILSS values of 47.4 ± 2.2 MPa which are close to the base laminate (52.4 ± 3.1 MPa). The removal of the PF provided larger porous in the CNT network, making the impregnation by epoxy easier in the BP/RPF which resulted in improved shear properties compared to GF/EP/BP/PF samples.     

Preparation of high‐k composites with low dielectric loss based on the double‐layer coaxial structure of inorganic/polymer

This study presents a novel and simple modification of cladding multiwalled carbon nanotubes (MWCNTs) using organic polymer and inorganic nanoparticles to synthesize a product, which has a double‐cladding coaxial structure and can be applied as filler in the dielectric field. The first layer of MWCNTs was coated with polyaniline (PANI) through the oxidation–reduction reaction mechanism using Ce(NH₄)₂(NO₃)₆ as oxidizing agent and metal precursor of cerium oxide. Cerium ions on the second cladding layer of MWCNTs were directly deposited from the solution to the surface of the PANI layer forming the double‐cladding hybrid (CeO₂/PANI@MWCNTs). The external inorganic layer provides an insulating shell, which can prevent the contact between the conductive particles and hinder the migration of electrons between the MWCNTs. The intermediate layer of PANI provides the bonding between CeO₂ and the conductive core of MWCNTs, which also shows lower conductivity than carbon nanotubes. The CeO₂/PANI@MWCNTs were compounded with epoxy (EP) resin and formed a dielectric material with the advantage of reducing dielectric loss while ensuring high dielectric constant. The dielectric constant of the coated MWCNTs/EP composites was 194.90 at 10³ Hz with the content of fillers reaching 30 wt %, which is 28 times that of the pure EP. Accordingly, the dielectric loss of 30 wt % coated MWCNTs/EP composites was only 0.09 at 10³ Hz, which is only 2.25 times that of the pure EP. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46299.     

Batch foaming of carboxylated multiwalled carbon nanotube/poly(ether imide) nanocomposites: The influence of the carbon nanotube aspect ratio on the cellular morphology

A series of microcellular poly(ether imide) (PEI) foams and nanocellular carboxylated multiwalled carbon nanotube (MWCNT‐COOH)/PEI foams were prepared by the batch foaming method. MWCNT‐COOHs with different aspect ratios were introduced into the PEI matrix as heterogeneous nucleation agents to improve the cell morphology of the microcellular PEI foams. The effect of the aspect ratio of the MWCNT‐COOHs on the cellular morphology, and gas diffusion is discussed. The results show that with the addition of MWCNT‐COOH, the sorption curve showed a slight reduction of carbon dioxide solubility, but the gas diffusion rate could be improved. The proper aspect ratio of MWCNT‐COOH could improve the cellular morphology under the same foaming conditions, in which m‐MWCNT‐COOH (aspect ratio ≈ 1333) was the best heterogeneous nucleation agent. When the foaming temperature was 170°C, the cell size and cell density of nanocellular m‐MWCNT‐COOH reduced to 180 nm and increased to 1.58 × 10¹³ cells/cm³, respectively. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42325.     

Quantification of carbon nanotube dispersion and its correlation with mechanical and thermal properties of epoxy nanocomposites

An experimental study is carried out to quantitatively assess the dispersion quality of carbon nanotubes (CNTs) in epoxy matrix as a function of CNT variant and weight fraction. To this end, two weight fractions (0.05% and 0.25%) of as-grown, oxidized, and functionalized CNTs are used to process CNT/epoxy nanocomposites. Scanning electron microscopy, X-ray diffraction, and Fourier transform infrared analysis of different variants of CNTs are used to establish the efficiency of purification route. While the relative change in mechanical properties is investigated through tensile and micro-hardness testing, thermal conductivity of different nanocomposites is measured to characterize the effect of CNT addition on the average thermal properties of epoxy. Later on, a quantitative analysis is carried out to establish the relationship between the observed improvements in average composite properties with the dispersion quality of CNTs in epoxy. It is shown that carboxylic (-COOH) functionalization reduces the average CNT agglomerate size and thus ensures better dispersion of CNTs in epoxy even at higher CNT weight fraction. The improved dispersion leads to enhanced interfacial interaction at the CNT/epoxy interface and hence provides higher relative improvement in nanocomposite properties compared to the samples prepared using as-grown and oxidized CNTs. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48879.     

Simultaneous enhancements in the mechanical,thermal, and electrical performances of glass‐fiber‐reinforced cyanate ester/epoxy composites with plasma‐functionalized carbon nanotubes at different temperatures

Woven glass‐fiber‐reinforced cyanate ester/epoxy composites modified with plasma‐functionalized multiwalled carbon nanotubes (MWCNTs) were prepared. The mechanical, thermal, and electrical properties of the composites were investigated at different temperatures. The results show that the interlaminar shear strength, thermal conductivity, and electrical conductivity of the composites at room temperature and the cryogenic temperatures were enhanced simultaneously by the incorporation of MWCNTs, whereas the nonconductive behavior of the composites as electrical insulating materials was not changed. Meanwhile, the reinforcing mechanism was also examined on the basis of the microstructure of the composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41418.     

A liquid‐like multiwalled carbon nanotube derivative and its epoxy nanocomposites

Multiwall carbon nanotubes (MWCNTs) with liquid‐like behavior at room temperature were prepared with sulfonic acid terminated organosilanes as corona and tertiary amine as canopy. The liquid‐like MWCNT derivative had low viscosity at room temperature (3.89 Pa s at 20°C) and exhibited non‐Newtonian shear‐thinning behavior. The weight fraction of MWCNT in the derivative was 16.72%. The MWCNT derivative showed very good dispersion in organic solvents, such as ethanol and acetone. The liquid‐like MWCNT derivative was incorporated into epoxy matrix to investigate the mechanical performance of the nanocomposites and the distribution of MWCNTs in the matrix. When the liquid‐like MWCNT derivative content was up to 1 wt %, the flexural strength and impact toughness of composites were 12.1 and 124% higher than the pure epoxy matrix, respectively. Transmission electron microscope (TEM) confirmed the very good dispersion of the liquid‐like MWCNT derivative in epoxy matrix. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2217–2224, 2013     

The effect of fluorosilicone modifiers on the carbon nanotube networks in epoxy matrix

Structure and properties of polymer compositions based on carbon nanotubes (CNTs) filled epoxy matrix containing fluorosilicone copolymers as additives is discussed. Electrical conductivity and dielectric (microwave) permittivity of the composites can be varied by approximately one order of magnitude without changing the CNT concentration, by careful selection of the additive type and concentration. The mutual solubility of the modifiers and epoxy is a key factor determining both rheological properties of the uncured compositions and electrical properties of cured CNT‐nanocomposites. CNT‐nanocomposites modified with amino‐functional (i.e., epoxy crosslinkable) copolymers demonstrate improved electrical conductivity values at increased additive concentration, connected with the formation of specific segregated microstructure. Fluorosilicone additives added in a specific amount also allow for a decrease of the viscosity of uncured epoxy CNT‐nanocomposites, improving their processability. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46539.     

Improvement of carbon nanotube dispersion in electrospun polyacrylonitrile fiber through plasma surface modification

In this study, surfaces of multiwalled carbon nanotubes (CNTs) were functionalized with poly(hexafluorobutyl acrylate) (PHFBA) thin film using a rotating-bed plasma-enhanced chemical vapor deposition (PECVD) method without imparting any defects on their surfaces. Polyacrylonitrile (PAN) electrospun polymer fiber mats and composite fiber mats with CNTs and functionalized CNTs (f-CNTs) were prepared. The wettability and chemical and morphological properties of the synthesized fiber mats were investigated, and the dispersion of CNTs and f-CNTs in the polymer matrix was compared according to the contact angle results of electrospun polymer mats. According to the chemical and morphological characterization results, PHFBA-coated CNTs were dispersed more uniformly in the polymer matrix than the uncoated CNTs. The f-CNTs/PAN composite fiber mat exhibits a lower surface energy than the pristine CNTs/PAN fiber mat. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47768.     

Mechanical,rheological, and electrical properties of multiwalled carbon nanotube reinforced ASA/Na‐ionomer blend

Varying amounts of multiwalled carbon nanotubes (MWCNTs) was melt‐extruded with the acrylonitrile‐styrene‐acrylate (ASA)/Na‐ionomer blend, and mechanical, rheological, and electrical properties were studied Optical micrographs show good dispersion level at low MWCNT content and network formation at higher nanotubes percentage. DC conductivity model data shows percolation threshold reached at 1% MWCNT content and after percolation, two‐dimensional network structure was formed. The “peak and valley” type surface topology of matrix may be responsible for low percolation threshold limit. The polymer/nanotubes interactions at low MWCNT content increased the mechanical strengths, which were reduced by the network structure and agglomerates of nanotubes at higher nanotubes content. The MWCNTs interacted differently with the architecturally complex polymer chains and controlled chain dynamics accordingly. The Carreau‐Yasuda model was found fit to viscosity data and the model parameters data suggest the zero shear viscosity is function of MWCNTs content but the infinite shear viscosity is independent of nanoparticles content. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42516.     

The effect of temperature on fatigue strength of poly(ether-imide)/multiwalled carbon nanotube/carbon fibers composites for aeronautical application

This work concerns the fatigue behavior at three different temperature conditions (−40, 20, and 80°C) and the addition of multiwalled carbon nanotube (MWCNT) into a carbon-fiber reinforced poly(ether-imide) composite. The incorporation of MWCNT into the composite increased the tensile strength and Young's modulus by up 5 and 2%, respectively. At low temperature, the incorporation of the nanoparticles improved the fatigue strength of the laminates by 15%. The shear strength results obtained by interlaminar shear strength and compression shear test tests have shown an increase of about 16 and 58%, respectively, by the introduction of nanotubes into the laminates. Fractographic observations revealed that the surface of carbon nanotube laminate (PEI/MWCNT/CF) presented a ductile behavior, and differences in the fracture aspects of the material compared to the traditional PEI/CF laminate have been observed.     

Effect of low‐content carbon nanotubes on the dielectric and microwave absorption properties of graphite/polymer nanocomposites

Honeycomb cores (HCs) coated with graphite and multiwalled carbon nanotubes (MWCNTs) filled in a thermoplastic resin are proposed as microwave absorbers. The MWCNT contents varied from 0.2 to 0.6 wt % in a graphite‐filled (15 wt %) thermoplastic resin. The HCs were coated with three different types of coating materials for the sake of comparison: graphite, MWCNTs, and graphite plus MWCNTs. The dielectric properties [the real and imaginary parts of complex permittivity (ε′ and ε″, respectively)] and reflection loss (RL) of all of the coated HCs were measured and compared. We observed that the permittivities and RL increased significantly with increased weight percentage of the MWCNTs in the graphite‐filled thermoplastic resin. The RL measurements showed a maximum loss of ?20 dB around 7 GHz and a bandwidth of 2.7 GHz at ?10 dB in the HCs coated with the 0.4 wt % MWCNT plus graphite. There was also a shift in the RL peak position from the x band to the c band after the increase of MWCNT content. We also observed from the measurements that a combination of graphite and MWCNTs resulted in a broadband microwave absorber; a bandwidth of 13 GHz was observed for 80% RL when the MWCNT content increased to 0.6 wt % in the graphite‐incorporated resin. The possible mechanism that increased RL with the incorporation of MWCNTs in the graphite‐mixed thermoplastic resin is discussed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40891.     

Influence of processing condition and carbon nanotube on mechanical properties of injection molded multi‐walled carbon nanotube/poly(methyl methacrylate) nanocomposites

In this work, multi‐walled carbon nanotubes (MWCNT) and poly(methyl methacrylate) (PMMA) pellets were compounded via corotating twin‐screw extruder. The produced MWCNT/PMMA nanocomposite pellets were injection molded. The effect of MWCNT concentration, injection melt temperature and holding pressure on mechanical properties of the nanocomposites were investigated. To examine the mechanical properties of the MWCNT/PMMA nanocomposites, tensile test, charpy impact test, and Rockwell hardness are considered as the outputs. Design of experiments (DoE) is done by full factorial method. The morphology of the nanocomposites was performed using scanning electron microscopy (SEM). The results revealed when MWCNT concentration are increased from 0 to 1.5 wt %, tensile strength and elongation at break were reduced about 30 and 40%, respectively, but a slight increase in hardness was observed. In addition, highest impact strength belongs to the nanocomposite with 1 wt % MWCNT. This study also shows that processing condition significantly influence on mechanical behavior of the injection molded nanocomposite. In maximum holding pressure (100 bar), the nanocomposites show highest tensile strength, elongation, impact strength and hardness. According to findings, melt temperature has a trifle effect on elongation, but it has a remarkable influence on tensile strength. In the case of impact strength, higher melt temperature is favorable. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43738.     

Synergetic effects on the mechanical and fracture properties of epoxy composites with multiscale reinforcements: Carbon nanotubes and short carbon fibers

The ball‐milling/liquid‐phase oxidation (BMLPO) method was used to fabricate surface‐modified short carbon fibers (SCFs). Multiscale epoxy composites reinforced with a combination of SCFs and multiwalled carbon nanotubes (MWNTs) were prepared. Atomic force microscopy observations and contact angle measurement were used to investigate the modification effect of the BMLPO method. Mechanical tests and scanning electron microscopy observations were used to study the effects of the SCFs, MWNTs, and their combination on tensile properties, impact strength, and fracture toughness of the epoxy composites. The results show that the surface roughness of the SCFs after BMLPO treatment increased, and the wettability of the SCFs was improved as well. The combined use of the SCFs and MWNTs had a synergetic effect on the tensile strength, fracture toughness, and impact strength of the epoxy composites. The addition of MWNTs promoted the plastic deformation of the epoxy matrix and decreased the stress‐concentration level near the SCF/matrix interface; these were considered the main causes of the synergetic effect. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43500.     

Improving thermal conductivity and shear strength of carbon nanotubes/epoxy composites via thiol‐ene click reaction

This study investigates the effect of the thiol‐ene click reaction on thermal conductivity and shear strength of the epoxy composites reinforced by various silane‐functionalized hybrids of sulfhydryl‐grafted multi‐walled carbon nanotubes (SH‐MWCNTs) and vinyl‐grafted MWCNTs (CC‐MWCNTs). The results of Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, thermal gravimetric analysis (TGA), and transmission electron microscopy (TEM) show that the sulfhydryl groups and vinyl groups are successfully grafted onto the surface of MWCNTs, after treatment of MWCNT with triethoxyvinylsilane and 3‐mercaptopropyltrimethoxysilane, respectively. Scanning electron microscopy (SEM), HotDisk thermal constant analyzer (HotDisk), optical microscope, and differential scanning calorimetry (DSC) are used to characterize the resultant composites. It is demonstrated that the hybrid of 75 wt % SH‐MWCNTs and 25 wt % CC‐MWCNTs has better dispersion and stability in epoxy matrix, and shows a stronger synergistic effect in improving the thermal conductivity of epoxy composite via the thiol‐ene click reaction with 2,2′‐azobis(2‐methylpropionitrile) as thermal initiator. Furthermore, the tensile shear strength results of MWCNT/epoxy composites and the optical microscopy photographs of shear failure section indicate that the composite with the hybrid MWCNTs has higher shear strength than that with raw MWCNTs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44579.     

Alignment and properties of carbon nanotube buckypaper/liquid crystalline polymer composites

Carbon nanotubes (CNTs) have been recognized as a potential superior reinforcement for high‐performance, multifunctional composites. However, non‐uniform CNT dispersion within the polymer matrix, the lack of adequate adhesion between the constituents of the composites, and lack of nanotube alignment have hindered significant improvements in composite performance. In this study, we present the development of a layer‐by‐layer assembly method to produce high mechanical performance and electrical conductivity CNT‐reinforced liquid crystalline polymer (LCP) composites using CNT sheets or buckypaper (BP) and self‐reinforcing polyphenylene resin, Parmax. The Parmax/BP composite morphology, X‐ray diffraction, mechanical, thermal, and electrical properties have been investigated. SEM observations and X‐ray diffraction demonstrate alignment of the CNTs due to flow‐induced orientational ordering of LCP chains. The tensile strength and Young's modulus of the Parmax/BP nanocomposites with 6.23 wt % multi‐walled carbon nanotube content were 390 MPa and 33 GPa, respectively, which were substantially improved when compared to the neat LCP. Noticeable improvements in the thermal stability and glass transition temperature with increasing CNT content due to the restriction in chain mobility imposed by the CNTs was demonstrated. Moreover, the electrical conductivity of the composites increased sharply to 100.23 S/cm (from approximately 10^?13 S/cm) with the addition of CNT BP. These results suggest that the developed approach would be an effective method to fabricate high‐performance, multifunctional CNT/LCP nanocomposites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Novel method of dispersion of multiwalled carbon nanotubes in a flexible epoxy matrix

We describe a simple and novel method for dispersing multiwalled carbon nanotubes (MWCNTs) in a flexible epoxy matrix. The MWCNTs were modified with half‐neutralized dicarboxylic acids having different numbers of carbon atoms. The modified MWCNTs were prereacted with epoxy in the presence of triphenylphosphine. The dispersion of the MWCNTs and the enhancement in the tensile properties were found to be better for composites prepared with a solvent. Among the half‐neutralized dicarboxylic acids used, half‐neutralized adipic acid (HNAA) exhibited the best performance. Scanning electron microscopy and transmission electron microscopy studies clearly indicated an improvement in the level of dispersion of the MWCNTs with the addition of the modifier. The good dispersion of the MWCNTs and the resulting improvement in their properties were attributed to the cation–π interactions (the cation of HNAA and the π‐electron clouds of the MWCNTs) between the HNAA and MWCNTs and the chemical bonding of ? COOH groups of HNAA and the epoxy resin. The cation–π interaction and chemical bonding was assessed with Fourier transform infrared spectroscopy and Raman spectroscopy. This approach did not destroy the π–electron clouds of the MWCNTs in contrast to a chemical functionalization strategy. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2610–2618, 2013     

Effect of the filler structure of carbon nanomaterials on the electrical,thermal, and rheological properties of epoxy composites

Carbon nanotubes (CNTs) and graphene nanosheets (GNSs) were used as fillers in epoxy composites with the aim of increasing the electrical and thermal conductivities of the composites. The filling of pristine CNTs produced the highest electrical conductivity (σ), whereas a high CNT functionalization and the two‐dimensional planar structure of GNSs were promising for improving the thermal conductivity. A combination of CNTs and GNSs exploited the advantages of both. When the CNT fraction was larger than 50 wt %, a higher σ was obtained. When a small amount of functionalized CNTs was added to the GNSs, the thermal conductivity was also increased. The rheological measurements revealed the lowest complex viscosity for the GNS filling and showed the exciting advantages of an easy processing. As a result, the mixed filling also exhibited a much lower viscosity than the pure CNT fillings. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013