Influence of Carbon Black and Carbon Nanotubes on the Conductivity, Morphology, and Rheology of Conductive Ternary Polymer Blends.
Electrically conductive polymer composites consisting of conductive fillers such as carbon black (CB), carbon nanotubes (CNT), or graphene dispersed in an insulating polymer system are used in a broad array of industrial applications due to their unique thermal, mechanical, and electrical properties including tunable conductivity over a wide range. In many applications, a substantial concentration of conductive filler is required to achieve significant electrical conductivity, which results in decreased mechanical properties, increased melt viscosity, and higher costs.
CNT have a unique combination of mechanical, electrical, and thermal properties that make them excellent candidates to substitute or complement the conventional fillers in the fabrication of multifunctional polymer composites [1-5]. CNT have been found to increase the electrical conductivity of insulating polymers at relatively low concentrations compared to CB. A key reason behind CNT emergence as an efficient filler is its high aspect ratio (L/D) as compared to the conventional fillers like CB [6, 7], CNT composites are typically produced by one of three methods including solvent blending, melt processing , and in situ polymerization. At the nanoscale, the CNTs are inclined to aggregate which can reduce their effectiveness with respect to conductivity of the final composites. Therefore, in most cases, it is critically important to achieve good CNT dispersion. The controlled dispersion of CNTs in a polymer matrix remains a challenge, due to the strong van der Waals binding energies associated with the CNT aggregates. There has been extensive research on improving the dispersion of CNT in polymer matrix including the kinetics of the mixing process [9, 10], reactive blending [11, 12], and functionalization and physical modification of CNT [13-15]. It has also been reported that it is unlikely for high aspect ratio CNT particles to be localized at the interface from a thermodynamic standpoint .
Multiphase polymer blends have been used to reduce the percolation threshold with increased composite conductivity at reduced filler concentrations that minimizes detrimental impact on mechanical and rheological properties [17-26]. Triple percolation is a more recent approach to reduce the percolation threshold in electrically conductive polymer composites wherein immiscible ternary polymer blends are utilized in combination with the conductive filler . There has been a steady increase in research that has studied the phase morphology in ternary blends especially the tri-continuous structure. Previous work demonstrated that kinetic and thermodynamic parameters influenced the phase morphology and localization of the CB to increase electrical conductivity as a function of annealing time in CB-filled polypropylene (PP)/poly(methyl methacrylate) (PMMA)/ethylene acrylic acid copolymer (EAA) ternary polymer blends .
Zhao and coworkers achieved a percolation threshold of 0.3 wt% and a high dielectric constant in a PMMA/polystyrene (PS)/poly(vinylidene fluoride) (PVDF) ternary polymer blend containing multiwall CNT. The blends had a core-shell structure where the PS is the matrix, PVDF is the core, and the PMMA is the shell with the CNT selectively localized in the PMMA , Dou et al. [30-32] studied the morphology evolution of tri-continuous PVDF/PS/high density polyethylene (PVDF/PS/ HDPE) ternary blends with multiwall CNT selectively dispersed in the PS interphase resulting in a percolation threshold of 0.022 vol%. Cohen and coworkers investigated a PP/polyamide-12 (PA)/pyridine-modified poly(ethylene-co-methacrylic acid) (EMMA) system. The PP and PA were the major phases and the CNT were premixed with the pyridine-modified EMAA serving as the minor component that formed strong interactions confining the percolated network at the PP/PA interface. Panda et al.  investigated polyamide 6/PP/acrylonitrile-butadiene styrene (ABS) ternary systems with multiwall CNT, in which the multiwall CNT were found to exhibit a "compatibilization-like" action that manifested a reduction of average droplet size of the dispersed phases.
In this work, the influence of CB and multiwall CNT conductive fillers with different aspect ratios on the phase morphology, electrical properties, and rheological behavior in a PP/PMMA/EAA ternary polymer blend was studied. The PP/PMMA/(EAA-CNT) system was compared to two different PP/PMMA/(EAA-CB) systems. The electrical resistivity percolation behavior was investigated as a function of conductive filler content for the ternary polymer blends and single phase systems. The ternary blend phase morphology and conductive filler dispersion were characterized by multiple microscopy techniques. Rheology measurements at low frequency are sensitive to micro-structural changes and were used to probe the percolation including dispersion of conductive filler and formation of an interconnected filler network. The relationship between the phase morphology, electrical percolation threshold, and rheological behavior was analyzed.
The three polymers used in the preparation of the ternary polymer blend were PP (FF018F) from Braskem, PMMA (IF 850B) from LG Chemicals, and EAA (PRIMACOR[TM] 3004 copolymers) with 9.7 wt% acrylic acid from The Dow Chemical Company as in previous work . Two grades of CB with different colloidal properties including surface area measured by iodine adsorption number and aggregate size (pore volume or structure) measured by dibutyl phthalate (DBP) oil adsorption number were compared to multiwall CNT. The first CB (CB1) had a relatively low surface area (iodine adsorption number of 46 g/kg) and pore volume (DBP adsorption number of 95 mL/ 100 g). The second CB (CB2) was an extra-conductive CB (Ketjenblack EC-300J) from Akzo Nobel with a high surface area (iodine adsorption number of 800 mg/g) and pore volume (DBP adsorption number of 327 mL/100 g). The multiwall CNT produced by catalytic chemical vapor deposition and pre-mixed in the EAA polymer were provided by Arkema Inc. and had an average diameter of about 10 nm and a length of about 10 microns. All materials were used as received.
A series of PP/PMMA/EAA composites containing CB and CNT were prepared. The composite formulations are shown in Table 1. The conductive fillers (CB1, CB2, and CNT) were premixed in the EAA polymer phase at 9.3 vol% to form a masterbatch prior to compounding the composites where the conductive filler was preferentially distributed in the minor EAA phase.
The masterbatches and final composites were melt-mixed using an internal C.W. Brabender prep-mixer. For the CB master-batches, the CB and EAA polymer were directly compounded at 60 rpm for 10 min at 130[degrees]C. As aforementioned, the CNT were received as a masterbatch provided by the supplier. For the multiphase composites, the EAA-CB and EAA-CNT master-batches were mixed with the PP and PMMA base resins and compounded at 190[degrees]C at 60 rpm for 5 min.
Prior to testing, the polymer composites were compression molded at 190[degrees]C and 3.45 MPa for 3 min, then the pressure was increased to 17 MPa followed by thermal annealing at 190[degrees]C for 30 min. After 30 min, the composites were cooled at 17 MPa pressure to 30[degrees]C with chilled water.
The electrical resistivities of the polymer composites were obtained from compression molded samples. Low resistance measurements (<[10.sup.8] [OMEGA]) were conducted using a Keithley 2700 Integra Series digital multimeter with 2-point probe. At least two samples (101.6 mm long by 50.8 mm wide by 1.9 mm thick) were tested for each formulation. Silver paint (conductive silver #4817N) was applied to minimize contact resistance between the samples and electrodes. High resistance measurements (>[10.sup.8] [OMEGA]) were conducted using a Keithley Model 6517B electrometer high resistance meter coupled with a Model 8009 resistivity test chamber. Circular disk samples with 76.2 mm diameter and 1.9 mm thick were tested.
Samples were excised from plaques in 1 cm X 1 cm squares and trimmed down with a razor blade to have a block face roughly <0.5 mm X 0.5 mm. These rough block faces were then polished with a Diatome Cryo 45 Trim knife, stained in a 0.5% Ru[O.sub.4] solution for 16 hours and then rinsed with deionized water. For Transmission Electron Microscopy (TEM), 70-100 nm thick sections were then cut from the stained block face using a Leica UC7 microtome at room temperature with a Diatome Sonic knife (Voltage: 2.1, Frequency: 33.4 Hz) and collected on Formvar coated TEM grids. TEM images were obtained with a FEI Techni at 120 keV. Scanning Electron Microscopy (SEM) samples were the remaining Ru[O.sub.4] stained block faces from TEM sample preparation. SEM images were obtained with a Hitachi 3400 in variable pressure mode (25 Pa) using a backscatter detector.
Dynamic oscillatory shear rheology was conducted with an ARES oscillatory shear rheometer for analysis of viscoelastic behavior. The oscillatory shear measurements were conducted at 190[degrees]C with the parallel plate geometry (plate diameter of 25 mm) under a nitrogen environment. Frequency sweeps were carried out at 0.25% strain between a frequency of 0.1 and 100 rad/s. The strain amplitude was chosen within the linear viscoelastic region. The rheology experiments were conducted on samples that had been annealed at 190[degrees]C for 30 min.
RESULTS AND DISCUSSION
Electrical Resistivity of the Composites
The percolation behavior as a function of conductive filler content was compared for the ternary polymer blends and single-phase polymer systems. It is generally accepted that the critical conductive filler loading is referred to as the critical percolation concentration, [[phi].sub.c], for each system where the first continuous conductive filler network is formed throughout the matrix and the resistivity of the material drops sharply. The power-law equation [sigma] = [[sigma].sub.0] [([phi] - [[phi].sub.c]).sup.t] is widely used to evaluate the relationship between filler loading and electrical conductivity where [sigma] is the electrical conductivity of the composites, [[sigma].sub.o] is a constant related to the intrinsic conductivity of the conductive filler, [phi] is the volume fraction of the conductive filler, [[phi].sub.c] is the volume fraction at the critical percolation threshold, and t is the power law exponent related to the mechanism of conductive network formation in the system.
It would be desirable to change the conductive filler volume percent as an independent variable to establish the percolation behavior. However, in this study the conductive filler was premixed with the EAA phase prior to preparation of the final composite and therefore both the EAA and conductive filler concentrations varied. In one respect, this provided an indication of the impact of both filler content and volume fraction of the minor EAA component for each type of conductive filler.
It is known that CB with smaller particle size (lower surface area) and larger aggregate size (higher structure) will result in higher conductivity at lower loading but have higher viscosity, be harder to disperse in the polymer matrix, and tend to be higher in cost , On the other hand, CB with larger particle size and smaller aggregate size will be lower cost, easier to disperse in the polymer matrix, and have a lower viscosity, but will require a much higher loading to achieve percolation. For CNT, the high aspect ratio leads to much higher conductivity at low loading, but subsequently results in much higher viscosity and makes it more difficult to disperse. Therefore, it becomes crucial to choose the right balance of conductive filler and polymer blend morphology to achieve the desired composite performance.
The percolation behavior of the single and ternary composites is shown in Fig. 1. At low concentrations of filler, the resistivity is high and gradually decreases with increasing filler content. The best fitting value for the critical concentration of the ternary composites with CB1, CB2, and CNT were [[phi].sub.c] = 0.58 vol%, 0.20 vol%, and 0.17 vol% which are more than 8 times lower than [[phi].sub.c] = 5.0 vol%, 2.0 vol%, and 1.5 vol% for the single phase systems, respectively. In addition to [[phi].sub.c], the percolation threshold is also defined by the filler concentration at the inflection point on the percolation curve (evident in Fig. 1) where the system transitions from insulating to conductive and particle network formation increases, which occurs at about 1.0 vol% for CB1 and about 0.5% for CB2 and CNT.
In all cases, the ternary polymer composite systems were found to have a sharp decrease in electrical resistivity over a narrow conductive filler range whereas the single phase systems reached percolation over a broader range. For example, the electrical resistivity of the ternary composite with CNT dropped from 2.47 x [10.sup.15] [OMEGA]-cm to 4.02 x [10.sup.3] [OMEGA]-cm with an increase in CNT content from 0.15 to 0.80 vol%, whereas the single phase composite dropped from 2.40 X [10.sup.16] [OMEGA]-cm to 2.95 x [10.sup.5] [OMEGA]-cm with an increase in CNT content over a broad range from 1.0% to 5.0 vol%. The low surface area, low structure CB1 inherently has the lowest conductivity of the three fillers in the study; however, the use of the multiphase polymer blend significantly lowered the percolation threshold and required 80% less CB1 (1.9 vol% instead of 9.33 vol%) to achieve conductivity in the semiconducting range of [10.sup.4] [ohms]-cm (Fig. 1). Interestingly, CB2 was found to have similar percolation behavior to the CNT.
TEM was used to determine the dispersion of the conductive fillers. TEM of the EAA masterbatches (Fig. 2) showed that in the micron size range and greater (Fig. 2A-C) all the conductive fillers displayed fairly uniform dispersion. Some clusters of the CNT were observed, as depicted in the center of Fig. 2C. At higher magnification (Fig. 2D-F) individual dispersed particles of the conductive fillers can be seen as well as crystalline lamellae of the EAA. As mentioned above, CB2 is a very high surface area material that falls into the extra conductive family of carbon blacks that is more graphitic than traditional furnace blacks like CB1. The structure of CB1 and CB2 as compared to the CNT can be seen in Fig. 2. The combination of the high surface area for CB2 and some clusters of CNT may explain why the CB2 was found to have similar percolation behavior to the CNT (Fig. 1). The conductive filler distribution was also investigated by TEM for the ternary blends. Example micrographs (Fig. 3) show that all three conductive filler types remained strongly partitioned into the EAA phase and uniformly distributed in that phase.
The phase morphology of the ternary blends was investigated using SEM (Fig. 4). Comparison of the TEM and SEM micrographs indicates the bright domains in the SEM correspond to the EAA-conductive filler. For example, Figs. 3A and 4 compares the CB1-110 TEM and SEM, respectively. The darker regions are the PMMA and the intermediate gray phase is the PP. The samples with CB 1 show a three-phase morphology with the EAA-CB1 predominantly at the interface between the PP and PMMA. This is consistent with what has been observed in previous work , At the other extreme, in the CNT samples a portion of the EAA-CNT is at the PP-PMMA interface and the other portion is dispersed in the PP phase. The fraction of the EAA dispersed in the PP phase is a strong function of the fraction of EAA in the blends, with roughly half the EAA at the interface in the sample with 5% EAA while most of the EAA is in the PP phase in the sample with 18.1% EAA. The CB2 morphology is intermediate between the CB1 and CNT but is notable in that a substantial fraction of the EAA that is dispersed in the PP at 18.1% EAA.
In both the CB2 and CNT samples, the characteristic size scale of the phase separation between the PP and PMMA is smaller by at least a factor of 2 than in the CB1 sample. Compared to the morphology of the ternary blends composed of EAA without any filler, the phase domains for the samples with filler are much smaller on average. This was found to be particularly true for the high aspect ratio CB2 and CNT samples. One explanation for this observation is that the high aspect ratio of the CB2 and CNT increases the EAA phase viscosity and slows down phase coalescences and leads to fragmentation of the EAA domains. Gubbels and coworkers found that the phase morphology of polymer blends was stabilized in the presence of CB particles and slowing down of the phase coalescence process was attributed to the increase in viscosity of one of the phases .
Rheological Behavior of the Composites
Dynamic rheological measurements have been utilized to predict phase inversion of binary polymer blends and assess filler dispersion in polymer melts [36, 37]. Phase continuity may be predicted by the Jordhamo relationship such that an increase in the volume fraction or decrease in melt viscosity of the minor component would lead to matrix continuity to enable electrical conductivity . In the previous work utilizing the PP/PMMA/ EAA ternary blend, the viscosity ratio for a 50/50 vol% split of the PP and PMMA major phases (each present at equal vol% in the overall compositions) was shown to be close to 1 through the frequency range resulting in a co-continuous morphology as predicted by the Jordhamo relationship and coincides with spreading of the minor EAA phase at the interphase due to a lower viscosity compared to the PP and PMMA phases .
The ternary composites in this study were found to be conductive with increasing filler concentration after 30 min annealing despite incomplete wetting of the minor EAA phase at the PP-PMMA interphase observed for the high structure CB2 and high aspect ratio CNT composites containing 1.9 vol% whereas continuity was achieved with the low structure CB1 (Fig. 4). Figure 5 shows the complex viscosity ([eta]*) as a function of frequency ([omega]) for the neat polymers and the filled EAA masterbatches. The complex viscosity of the EAA phase for the EAA-CB2 and EAA-CNT masterbatches was found to be quite high (shown in Fig. 5) such that it was higher than the PP and PMMA whereas the EAA-CB1 masterbatch viscosity was lower than the PP and PMMA phases. It is hypothesized that the kinetics of phase separation slow significantly as the viscosity of the minor phase increases causing a lack of complete continuity and spreading at the interphase after 30 min annealing. Based on the rheology and microscopy, it is proposed that beyond a critical loading of conductive filler particles, especially for the high aspect ratio CB2 and CNT, phase separation is slowed significantly due to the aggregation of particles into a network formation within the EAA phase causing a significant increase in phase viscosity. Li et al.  described this phenomenon with the preparation of co-continuous microstructured polymer blends and nanoparticles by formation of a percolating network of particles within one phase of a polymer mixture undergoing spinodal decomposition. This is analogous to bi-continuous interfacially jammed emulsion gels (bijels) as non-equilibrium structures formed by jamming of colloidal particles at the interface between two partially miscible materials undergoing spinodal decomposition with the onset of jamming determined by the overall colloid volume fraction [40-42].
The EAA-CB2 and EAA-CNT phases would be expected to further coarsen over time and yield a more complete continuous morphology of increasing size as evident in the previous work where the EAA-CB2 phase was found to be almost entirely at the PP-PMMA interface . It is important to note that the EAA-CB2 masterbatch in the previous work contained three times less CB than in this study and further supports the effect of lower viscosity on the evolution of the tri-continuous phase morphology.
The viscoelastic behavior in the low frequency region is sensitive to microstructural changes of the composite material, which may serve as an indication of changes in blend morphology as well as the dispersion of CB . It is generally known that the formation of an interconnected network structure of anisometric fillers in a polymer matrix results in an apparent yield stress which is visible in dynamic measurements by a non-Newtonian behavior of the [eta]*, a plateau in G' and G" (more pronounced in G'), and onset of a loss tangent (tan [delta]) peak in the low frequency region [44, 45]. The G' and tan [delta] in the low frequency regime are sensitive measures of the microstructure in the melt where time does not limit molecular relaxation processes . As the conductive filler content increases in the composite system, filler-filler interactions begin to dominate, impeding the motion of the polymers, eventually leading to percolation and the formation of an interconnected network structure.
To understand the rheological behavior of the ternary composites with each conductive filler, the effect of increasing conductive filler concentration was considered. Figs. 6-8 show [eta]*, G', G", and tan [delta] as a function of frequency and increasing filler concentration for the CB1, CB2, and CNT-based composites, respectively. The ternary composites exhibited similar, converging rheological responses at frequency greater than 1 rad/s while the larger differences are observed in the low frequency region. The [eta]* was found to increase with increasing filler content and exhibit non-Newtonian behavior across the frequency range. The G' appears to reach the onset of a plateau (observed as a break in the G' curve) at low frequencies starting at about 1.0 vol% for the CB1 system while at 0.5 vol% it is already visible for the CB2 and CNT systems. The increasing G', especially at low frequency, suggests a more elastic structure where molecular motion is inhibited by increasing particle network formation within the EAA phase. The tan [delta] decreases with increasing filler concentration and peaks at about 1.0 vol% for CB1 and 0.5 vol% for CB2 and CNT indicating a transition from a viscouslike behavior (tan [delta] < 1) to a more elastic-like behavior with longer relaxation times (tan [delta] < 1) as a result of the particle network formation as evident from the TEM micrographs (shown in Fig. 3).
The effect of filler type at equivalent loading on the rheological behavior was compared. Figure 9 compares the [eta]*, G', G", tan [delta] as a function of frequency for the ternary composites containing 1.9 vol% conductive filler. The ternary composites had similar [eta]*, G', and tan [delta] at 0.5 vol% loading. The CB2 and CNT composites began to gradually show differences at 1.0 vol% becoming more significant at 1.9 vol% (Fig. 9) compared to CB 1. The rheological behavior of the ternary composites can be attributed to the increasing particle network formation within the EAA phase, consistent with the increase in conductivity of the CB2 and CNT compared to CB1 at equivalent loading (Fig. 1)
This work investigated the effect of different CB and multiwall CNT conductive fillers with a range of aspect ratios on the phase morphology, electrical properties, and rheological behavior in a PP/PMMA/EAA ternary polymer blend with the PP and PMMA as the two major continuous phases and EAA-filler as a third minor component. The conductive filler was pre-mixed and localized within the EAA minor phase. The critical electrical percolation threshold for the ternary conductive polymer composites was found to be around 0.5% vol% for the PP/ PMMA/(EAA-CB1) and 0.2 vol% for the PP/PMMA/(EAACB2) and PP/PMMA/(EAA-CNT), which are more than 8 times lower than for the single phase systems. The rheological threshold coincided with the electrical resistivity percolation threshold inversion point, which was found to be around 1.0 vol% for the CB 1 system and 0.5 vol% for the CB2 and CNT systems. This suggests that the rheological response is sensitive to the interconnected network formation of the conductive filler, which is also directly related to electrical conductivity.
The conductive fillers were found to be uniformly distributed in the EAA matrix, however, some clusters were observed in the case of CNT. The phase morphology of the CB 1 containing blends showed a tri-continuous three-phase morphology with the EAA-CB1 predominantly at the interface between the PP and PMMA consistent with what has been observed in previous work. However, for the EAA-CB2 and EAA-CNT containing blends, a substantial fraction of the EAA-CB2 and EAA-CNT phases were found to be dispersed in the PP phase. The characteristic size scale of the phase separation between the PP and PMMA in the CB2 and CNT system is smaller by at least a factor of 2 than in the CB 1 sample. It was proposed that beyond a critical loading of conductive filler particles in the minor EAA phase, especially for high aspect ratio fillers such as the CB2 and CNT, phase separation is slowed significantly due to the aggregation of particles into a network formation within the EAA phase causing a significant increase in phase viscosity.
Ternary polymer blends offer a potential route to prepare conductive composites using high aspect ratio fillers with stable phase morphology and significantly lower percolation threshold. The results are consistent with the hypothesis that the kinetics of phase separation and resulting formation of a tri-continuous morphology are dictated by the viscosity of the minor phase relative to the two major phases, suggesting that the conductive minor phase viscosity should be optimized to that of the major phases when designing the final composite.
We are thankful to The Dow Chemical Company for the support of this research. We are greatly indebted to the reviewers for their helpful comments and suggestions.
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Paul J. Brigandi (ID), (1,2) Jeffrey M. Cogen, (1) John R. Reffner, (1) Casey A. Wolf,1 Raymond A. Pearson2
(1) The Dow Chemical Company, 400 Areola Road, Collegeville, Pennsylvania 19426-2914
(2) Center for Polymer Science and Engineering, Lehigh University, 5 East Packer Ave, Bethlehem, Pennsylvania 18015- 3195
Correspondence to: Paul J. Brigandi; e-mail: firstname.lastname@example.org
Published online in Wiley Online Library (wileyonlinelibrary.com).
Caption: FIG. 1. Percolation behavior of single and ternary polymer composites comparing CB and CNT conductive fillers at 23[degrees]C. The percolation threshold and [[phi].sub.c] are illustrated in the PP/PMMA/(EAA-CB1) for reference. [Color figure can be viewed at wileyonlinelibrary.com]
Caption: FIG. 2. TEM showing the conductive filler distribution in the EAA masterbatches. (A) EAA-CB 1, (B) EAA-CB2 and (C) EAA-CNT at low magnification and (D) EAA-CB 1, (E) EAA-CB2 and (F) EAA-CNT at high magnification.
Caption: FIG. 3. TEM of the ternary blends with EAA-CB1 at (A) 11.0 vol% and (D) 20.0 vol%, with EAA-CB2 at (B) 11.0 vol% and (E) 20.0 vol%, and EAA-CNT at (C) 5.5 vol%.
Caption: FIG. 4. SEM micrographs of the ternary composites as a function of filler type with varying filler and EAA volume percent.
Caption: FIG. 5. Complex viscosity of the polymers and EAA masterbatches as a function of conductive filler type at 190[degrees]C. [Color figure can be viewed at wileyonlinelibrary.com]
Caption: FIG. 6. Complex viscosity, storage modulus, loss modulus, and tan [delta] as a function of frequency at 190[degrees]C for the PP/PMMA/(EAA-CB 1). [Color figure can be viewed at wileyonlinelibrary.com]
Caption: FIG. 7. Complex viscosity, storage modulus, loss modulus, and tan [delta] as a function of frequency at 190[degrees]C for the PP/PMMA/(EAA-CB2). [Color figure can be viewed at wileyonlinelibrary.com]
Caption: FIG. 8. Complex viscosity, storage modulus, loss modulus, and tan [delta] as a function of frequency at 190[degrees]C for the PP/PMMA/(EAA-CNT). [Color figure can be viewed at wileyonlinelibrary.com]
Caption: FIG. 9. Complex viscosity, storage modulus, loss modulus, and tan [delta] as a function of frequency for the ternary composites containing 1.9 vol% conductive filler at 190[degrees]C. [Color figure can be viewed at wileyonlinelibrary.com]
TABLE 1. Compositions of the multiphase conductive polymer composites. Composite PMMA (vol%) PP (vol%) EAA-CB1 (vol%) CB1-25 48.75 48.75 2.50 CB1-55 47.25 47.25 5.50 CB1-85 45.75 45.75 8.50 CB1-110 44.50 44.50 11.00 CB1-200 40.00 40.00 20.00 CB1-322 33.90 33.90 32.20 CB2-05 49.75 49.75 CB2-15 49.25 49.25 CB2-25 48.75 48.75 CB2-55 47.25 47.25 CB2-85 45.75 45.75 CB2-110 44.50 44.50 CB2-160 42.00 42.00 CB2-200 40.00 40.00 CNT-05 49.75 49.75 CNT-15 49.25 49.25 CNT-25 48.75 48.75 CNT-55 47.25 47.25 CNT-85 45.75 45.75 CNT-110 44.50 44.50 CNT-160 42.00 42.00 CNT-200 40.00 40.00 Composite EAA-CB2 (vol%) EAA-CNT (vol%) CB1-25 CB1-55 CB1-85 CB1-110 CB1-200 CB1-322 CB2-05 0.50 CB2-15 1.50 CB2-25 2.50 CB2-55 5.50 CB2-85 8.50 CB2-110 11.00 CB2-160 16.00 CB2-200 20.00 CNT-05 0.50 CNT-15 1.50 CNT-25 2.50 CNT-55 5.50 CNT-85 8.50 CNT-110 11.00 CNT-160 16.00 CNT-200 20.00
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|Author:||Brigandi, Paul J.; Cogen, Jeffrey M.; Reffner, John R.; Wolf, Casey A.; Pearson, Raymond A.|
|Publication:||Polymer Engineering and Science|
|Date:||Dec 1, 2017|
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