High-density Polyethylene Matrices Research Articles

Antimicrobial silver loading onto reused high-density polyethylene matrices grafted with poly(4-vinylpyridine)

High-density polyethylene HDPE is a highly polluting plastic, and its reuse, reprocessing and modification are subjects of current research to mitigate environmental pollution. In recent times, it has been modified for specialized purposes as a harmless and resistant polymer. The present work details the modification of HDPE (obtained from Bonafont, Coke, and Gatorade caps) with the monomer 4-vinylpyridine (4VP) via radiation-induced grafting copolymerization initiated by gamma rays from a Co-60 source and with the subsequent Ag(I) loading using the reagent AgNO3 in aqueous medium. Poly(4VP) is widely used to retain metals and manufacture pH-responsive polymers, while Ag(I) is a recognized bactericide harmless to humans at therapeutic concentrations; therefore, both poly4VP and Ag(I) can work in a synergistic system against pathologic bacteria as is here proposed. We advance a favorable antimicrobial activity of the Ag-loaded graft copolymers evaluated in vitro with Kirby-Bauer tests against Pseudomonas aeruginosa and Staphylococcus aureus. Additionally, FTIR-ATR, TGA, contact angle, swelling, and pH response were carried out to complete the characterization.

Mechanical, Thermal Properties of Virgin, Recycled and Mixed High-Density Polyethylene Matrices and Wood Plastic Composites with Plywood Sanding Dust

Virgin high-density polyethylene (vHDPE), recycled (rHDPE), and mixed vHDPE/rHDPE matrices and wood plastic composites based on these mixtures + 50 wt.% of plywood sanding dust (PSD) and 3 wt.% coupling agent maleated polyethylene (MAPE) physical-mechanical properties (tensile, flexural strength and modulus, impact strength, and microhardness) were investigated. It was observed that all defined properties depend on the content of rHDPE in the pure polymer matrix and corresponding WPCs. Tensile strength and modulus decreased a bit, but flexural modulus actually had no changes. At the same time, a decrease in impact strength and a significant increase (up to 2 times) in microhardness are observed. From all the investigated matrices, the most perspective seems to be the matrix with a vHDPE/rHDPE ratio of 75/25, whose mechanical properties are acceptable for the preparation of the WPCs based on plywood sanding dust. The compatibilization possibilities tests of different mixed matrices done by the DSC method in the air showed that the mixed vHDPE/rHDPE compositions compatibility is sufficiently good at different proportions. For all mixed matrices, only one relatively symmetric band with one peak of melting was observed. Differential scanning calorimetry (DSC) tests in an inert environment showed that during the first heating cycle, HDPE components are only partially compatible (two peaks of melting temperatures are possible to fix). On the contrary, after the cooling and crystallization processes, during the second heating of the same sample, these two bands completely merge, and like in the air, only one maximum melting temperature peak was observed. The values of thermal oxidation temperature and melting temperature are the highest for virgin vHDPE but the lowest for rHDPE. The values of all corresponding parameters of mixed matrices reduce proportionally with an increase in rHDPE content in the mixtures.

Carbon nanotube network formation and configuration/morphology on reinforcing and conductive performance of polymer-based nanocomposites

The present research work shows that carbon nanotube network formation and configuration/morphology play significant role in mechanical and conductive performance of polymer-based nanocomposites. Using several experimental techniques and theoretical approaches, the main entities of the established networks with aligned and random morphology were identified, the underlying mechanisms of network formation and the nature of its building blocks were revealed, and the corresponding network effects on the mechanical and electrical performances of such nanocomposites using single-walled carbon nanotubes in low- and high-density polyethylene matrices were thoroughly studied. Results show that the formed network is in majority constructed from nanotube bundles, considered as stiff rod-like Brownian particles, geometrically entangled at the critical volume fraction φcv (geometrical percolation threshold). The geometrical percolation threshold was found to be independent of the network morphology (aligned of injection molded samples and random of compression molded samples). Moreover, the mechanical and rheological properties were found to be independent of the nanocomposite morphology. However, the electrical performance of such materials was surprisingly different, strongly dependent on the morphology (aligned versus random as defined above). The random configuration significantly decreases the transition of the nanocomposites from isolator to conductor. The electrical percolation threshold, φcve, was found to be by one order of magnitude lower than the corresponding geometrical threshold, thus profoundly improving the conductivity of such nanocomposites. This key discovery enables the production of not only highly reinforced and conductive nanocomposites, but also the ones with remarkable conductivity and flexibility with minimal addition carbon nanotubes.

The Effect of the Addition of Copper Particles in High-Density Recycled Polyethylene Matrices by Extrusion.

In this study, the effect of the recycling process and copper particle incorporation on virgin and recycled pellet HDPE were investigated by thermo-chemical analysis, mechanical characterization, and antibacterial analysis. Copper particles were added to pellet HDPE, virgin and recycled, using a tabletop single screw extruder. Some copper particles, called copper nano-particles (Cu-NPs), had a spherical morphology and an average particle size near 20 nm. The others had a cubic morphology and an average particle size close to 300 nm, labeled copper nano-cubes (Cu-NCs). The thermo-chemical analysis revealed that the degree of crystallization was not influenced by the recycling process: 55.38 % for virgin HDPE and 56.01% for recycled HDPE. The degree of crystallization decreased with the addition of the copper particles. Possibly due to a modification in the structure, packaging organization, and crystalline ordering, the recycled HDPE reached a degree of crystallization close to 44.78% with 0.5 wt.% copper nano-particles and close to 36.57% for the recycled HDPE modified with 0.7 wt.% Cu-NCs. Tensile tests revealed a slight reduction in the tensile strength related to the recycling process, being close to 26 MPa for the virgin HDPE and 15.99 MPa for the recycled HDPE, which was improved by adding copper particles, which were near 25.39 MPa for 0.7 wt.% copper nano-cubes. Antibacterial analysis showed a reduction in the viability of E. coli in virgin HDPE samples, which was close to 8% for HDPE containing copper nano-particles and lower than 2% for HDPE having copper nano-cubes. In contrast, the recycled HDPE revealed viability close to 95% for HDPE with copper nano-particles and nearly 50% for HDPE with copper nano-cubes. The viability of S. aureus for HDPE was lower than containing copper nano-particles and copper nano-cubes, which increased dramatically close to 80% for recycled HDPE with copper nano-particles 80% and 75% with copper nano-cubes.

Sensitive temperature-dependent phase resolution of polyethylene-clay nanocomposites

With the help of spectroscopic and differential scanning calorimetry (DSC) techniques, we have studied conformational and phase reorganizations as function of temperature in intercalated polymer-clay nanocomposites based on low-, middle-, and high-density polyethylene (PE) matrices. We show that Raman spectroscopy is sensitive to structural changes appearing during heating at much lower temperatures (about 47 °C) in comparison to DSC measurements. In fact, in the melting region where DSC traces show endotherms, Raman spectra reveal dramatic changes in the phase and conformational compositions of PE and PE-matrices within PE-clay nanocomposites. Noteworthy, the structural reorganization pathway, through which the semicrystalline nanocomposites transform into a melt state, depends primarily on the PE density and weakly on the filler (nanoclay). Moreover, the temperature-dependent crystallinity degree and the total amount of trans-conformers of the PE system are determined, and the evidence for the formation of intermediate crystal-like phase during heating is shown.

Towards Circular Economy by the Valorization of Different Waste Subproducts through Their Incorporation in Composite Materials: Ground Tire Rubber and Chicken Feathers.

Incorporation of residua into polymeric composites can be a successful approach to creating materials suitable for specific applications promoting a circular economy approach. Elastomeric (Ground Tire Rubber or GTR) and biogenic (chicken feathers or CFs) wastes were used to prepare polymeric composites in order to evaluate the tensile, acoustic and structural differences between both reinforcements. High-density polyethylene (HDPE), polypropylene (PP) and ethylene vinyl acetate (EVA) polymeric matrices were used. EVA matrix defines better compatibility with both reinforcement materials (GTR and CFs) than polyolefin matrices (HDPE and PP) as it has been corroborated by Fourier transform infrared spectroscopy (FTIR), termogravimetric analysis (TGA) and scanning electron microscopy (SEM). In addition, composites reinforced with GTR showed better acoustic properties than composites reinforced with CFs, due to the morphology of the reinforcing particles.

Effect of Filler Particle Size on the Recyclability of Fly Ash Filled HDPE Composites.

Fly ash polymer composites are innovative high-performance materials that reduce the environmental worries and disposal complications of heavy industry produced fly ash. This study developed and characterized such composites of high-density polyethylene (HDPE) matrices and found that the use of small (50–90 µm) particles of fly ash could give rise to the tensile modulus (~95%) and tensile strength (~7%) of their reinforced composites when compared to neat HDPE materials. While these results themselves convey a strong message of how fly ash can be effectively utilized, this was not the key aim of the current study. The study was extended to examine the effect of fly ash particle size on the recyclability of relevant HDPE composites. The extrusion-based multiple recycling of composites gave slightly lower mechanical properties, primarily due to filler/matrix delamination when large fly ash particles were used. Compared to freshly made fly ash-filled HDPE composites, although using small (50–90 µm) fly ash particles reduced the tensile modulus and tensile strength of recycled composites, the values were still far above those from neat HDPE materials. This novel insight directs the effective utilization of fly ash and provides long-term sustainable and economical solutions for their practical applicability.

Mechanisms of Single-Walled Carbon Nanotube Network Formation and Its Configuration in Polymer-Based Nanocomposites

The reinforcing and conductive performance of carbon nanotube polymer-based nanocomposites depends on the established network and its configuration. Within this study, we report on the underlying mechanisms of such network formation utilizing single-walled carbon nanotubes (SWCNTs) in low- and high-density polyethylene matrices. Mechanisms were theoretically evaluated through Doi–Edwards theory and experimentally confirmed through plasma etching coupled with electron microscopy as well as rheological flow tests. Results showed that the established network is constructed from SWCNT bundles, which geometrically entangle at a critical volume fraction Φv,crit (number of rods: β ≈ 30). Below Φv,crit, the bundles behave as individual units and may align in the flow direction. Above Φv,crit, the rotation of bundles is constrained by neighboring units, leading to a random network configuration. Moreover, the theory successfully explains SWCNT bundle behavior as a Brownian entity and predicts network formation through diminishing thermo- and hydro-dynamically driven diffusion, which can be manipulated during the production to enhance reinforcing/conductive functionality of such materials.

Mechanical Properties, Morphology and Elemental Composition of Composites Produced from Thermoplastic Polymers Filled with Egg Shell

Mechanical Properties, Morphology and Elemental Composition of Composites Produced from Thermoplastic Polymers Filled with Egg Shell

Mechanical Properties of Bamboo on Virgin and Recycled High-Density Polyethylene Matrix

Natural fiber-reinforced polymer composites are considered to have advantages over synthetic fibers, namely that they are more environmentally friendly but with better mechanical properties. The purpose of this study was to make a pure / recycled HDPE (High-Density Polyethylene) composite with bamboo fiber reinforcement by analyzing the mechanical properties of the composite. The method used in this research is experimental with a quantitative approach. Experiments are carried out by creating or manipulating certain conditions and by providing control over the test specimen. Pure / recycled HDPE plastics and bamboo fibers will be mixed in a machine extrusion molding with a temperature heater (160, 165, 170, 175) ° C. Before fabrication, bamboo fibers are treated with alkaline treatment, namely by immersing 5% NaOH. The ratio of mass fraction between vHDPE/rHDPE and bamboo fiber was 70%: 30%. This study evaluated the mechanical properties of HDPE-bamboo composites using Izod Impact testing with ASTM D 256-05 standards. Tests were carried out to analyze the differences between pure HDPE and recycled HDPE matrices on bamboo fiber reinforced composites. The mechanical test results showed that the impact strength on bamboo composites with recycled HDPE matrix was 2.69 (KJ / m2) while bamboo composites with pure HDPE matrices had an impact strength of 1.6 (KJ / m2). Thus, the mechanical properties measured by impact strength on composites with recycled HDPE matrices were better than composites with pure HDPE matrices. In accordance with the results of research that has been done, recycled HDPE can be used as a matrix composite with mechanical properties that are not too different from composites with pure HDPE matrices. This can be done as a means of utilizing recycled HDPE waste instead of pure HDPE.

Characteristics of recycled HDPE/bamboo fibre composite

Increasing the mechanical properties of recycling can be done by adding natural fibers into composite materials. The focus of this research is to develop a composite using bamboo as a reinforcing material and recycled High Density Polyethylene (HDPE) as a matrix using the extrusion method. This study aims to analyze the mechanical analysis between bamboo fiber-based composites using a pure HDPE matrix and composites using recycled HDPE matrices at a matrix volume fraction: 70%: 30% fiber. Mechanical tests were performed using the tensile testing machine model RAY-RAN Test Equipment M500-50CT with ASTM D 638 standards to evaluate the tensile strength and modulus of the composite. The results showed that the tensile strength and Young’s modulus of bamboo fiber reinforced rHDPE composites were 8.764 MPa and 52.0152 MPa, respectively. While the bamboo composite with a vHDPE matrix has a tensile strength of 9.3312 MPa and a Young Modulus value of 94.8468 MPa. Thus, bamboo fiber reinforced composites with pure HDPE matrix have better mechanical properties than bamboo composites with recycled HDPE matrices. Differences in matrix shape can affect composites resulting from such fibers.

Production of sustainable polymeric composites using grape pomace biomass

The incorporation of residues from a given crop into polymeric matrices is a valuable strategy to obtain multiple benefits, mostly environmental and economical, across the agricultural production chain. In this study, grape pomace residue from vineries were systematically combined with pinewood residues from sawmill to produce multi-component polymeric composites. A variety of composites were produced using polypropylene (PP) or high-density polyethylene (HDPE) matrices, with fixed polymer content at 50% and varied pine and grape pomace particle content. Mechanical and physical properties were investigated. The introduction of grape pomace into the composites led to reduced technical properties, but its composition with pinewood particles led to reasonably high mechanical performance. Although not suitable to be used as single component reinforcement for mechanical purposes, as in decks and handrails systems, grape pomace-based composites presented higher hydrophobicity. Such findings derive from (1) the non-fibrillar aspect of the residue, which usually leads to mechanical reinforcement in composites, and (2) due to the lipophilic nature of the chemical composition of such biomass. Grape pomace and wood particle utilization are a sustainable alternative to reduce petroleum-based plastics consumption in industries once the composites present 50% of plastic. This material is suitable in applications such as pallets, once the composites presented great behavior against water and good mechanical properties without no chemical treatment or coupling agents. Grape pomace opens a new possibility for extending service life for outdoor applications.

Nano-mesh superstructure in single-walled carbon nanotube/polyethylene nanocomposites, and its impact on rheological, thermal and mechanical properties

The mesh formation of single-walled carbon nanotube (SWCNT) superstructure, i.e. nano-mesh, in low- and high-density polyethylene (LDPE and HDPE) matrices was observed by using plasma etching technique and SEM analysis. Nano-mesh was established by two mechanisms: i) alignment of SWCNT bundles (forming network backbone) and ii) shish-kebab induced crystallization (forming network net). The network was formed at low SWCNT content due to the high aspect ratio of nano-filler, which additionally contributed to alignment. Established nano-mesh superstructure caused confinement effect disrupting crystallization and melting kinetics, which directly affected mechanical properties. Although mechanical properties of LDPE and HDPE nanocomposites profoundly improved, i.e. Young’s modulus increased for 230% and 30%, respectively, at only 1 wt% of SWCNTs, HDPE nanocomposites showed visible confinement that reduced effective reinforcement. It seems that HDPE nanocomposites cannot achieve full reinforcing potential since confinement effect restricts the crystal growth, which gradually reduces effective reinforcement in semi-dilute regime.

A biomaterial for scaffold applications: Thermal properties analysis of a PSZ-TiO2/HDPE system

High-density polyethylene (HDPE) matrices reinforced with titanium dioxide (TiO2) biocomposites are seen as promising biomaterials due to their superior properties. In this work, an attempt was made to study the effects of six biocomposites hybrid Titanium dioxide (TiO2) and yttria-stabilized zirconia (Y-PSZ) samples reinforced with high-density polyethylene (HDPE) matrices, split into two groups, in terms of withstanding the daily activity loads imposed by human bone grafting and repairs. The fabricated composites were investigated using the hot-pressing technique at different compression pressures and compounding temperature. To achieve characterization, thermal analysis of the process using differential scanning calorimetry (DSC) techniques was undertaken. To improve and verify the results, Design Expert 11.0 software and a response surface methodology (RSM) technique were used. For both nanofabricated types, the results showed that an increase in TiO2 ceramic filler from 1% to 10 %, caused percentage crystallization to increase by 14.58%. The heat of system fusion for the second fabricated system also decreased by 11%. These results show that this addition reduced the heat of system fusion by 109% compared with previous studies. The glass transition (onset) and end (melting) temperature also increased with increases in the applied compression pressure and hot-pressing temperature when a small value, 1%, of TiO2 ceramic nanoparticle fillers in the HDPE matrix. The temperature values were increased when using higher compression pressure of between 60 and 90 MPa, and the onset temperature reached a maximum value of 127 °C. This increase in onset temperature continued when using higher values of TiO2 Nanoceramic filler and the onset temperature reached its maximum value with 10% TiO2 and 2% PSZ Nanoceramic fillers added to the fabricated nanomaterial system. The differential scanning calorimetry (DSC) scanned curves and the 3D atomic force microscopy (AFM) microstructure and granularity distribution images for both fabricated nanocomposite systems clearly showed that the interconnections between the filler’s ceramic nanoparticles within the polymeric matrix offer high surface roughness values due to the excellent nanofiller particle distribution within the polymeric matrix.

On investigation of rheological, mechanical and morphological characteristics of waste polymer-based feedstock filament for 3D printing applications

In this study, a novel route for the preparation of feedstock filaments for fused deposition modelling from recycled high-density polyethylene (HDPE) and low-density polyethylene (LDPE) waste polymers has been explored. For improving the properties of HDPE/LDPE-recycled polymers, Fe powder has been reinforced through single-screw extrusion. It has been observed that Fe powder (from 0 wt% to 25 wt%) in the LDPE and HDPE matrices has shown increasing trend in melt flow index. Furthermore, Fe powder reinforcement resulted in 36.66% improvement in hardness of reinforced HDPE polymer and 64% in LDPE. Mechanical properties (peak elongation, peak strength, break strength and shore D hardness (SDH)) have been improved significantly with the addition of 6 wt% and 10 wt% reinforcement of Fe powder in the matrix of LDPE and HDPE, respectively. The results of study suggest that morphological properties, such as SDH and percentage porosity, have direct relation with mechanical properties as it has been found that the sample with better mechanical properties was also having high hardness and low porosity. Scanning electron microscopy and energy-dispersive X-ray spectroscopy have been performed on 3D printed functional parts and it has been observed that highly dense texture of HDPE and low surface roughness resulted in better mechanical properties.

On the stainless steel flakes reinforcement of polymer matrix particulate composites

The present paper is dealing with the reinforcement of epoxy and high density polyethylene (HDPE) matrices using stainless steel flakes (SSFs). Particulate composite specimens of different wt SSFs contents up to 10% were produced for each case of polymer matrix. The so-obtained SSFs/epoxy and SSFs/HDPE composites underwent tensile, three-point bending and compression tests. The tensile and flexural performance of the composites of both matrices seemed to be negatively affected by the SSF loading. However, the response on plastic deformation under tensile loading for the SSFs/HDPE composites was considerably enhanced for low SSFs contents. The compression response was enhanced in the case of SSFs/HDPE composites as well. The tensile, flexural and compression performance is being explained on the basis of the microstructural observations for each case of reinforced matrix.

DC electrorheological response of polyethylene/organically modified layered silicate nanocomposites

The present work reports the electrorheological (ER) response of high-density polyethylene (HDPE)/organically modified silicate layers nanocomposites based on four commercially available HDPE matrices. Two single-site catalyzed bimodal resins, one single-site catalyzed unimodal resin and one Ziegler–Natta catalyzed unimodal resin are studied. It is revealed that the distinct separation of the two modes of the bimodal HDPE resins significantly enhances the ER response. It is proposed that the slower structural relaxation modes introduced by higher molecular weight species in the bimodal HDPE matrices enhance the ER response of the nanocomposites. This is ascribed to the longer induction time for leaking current density, which is an indicator of mobility and release of immobilized cationic surfactants at the silicate layers surface induced by field exposure. It is found that the screening effect of prematurely released cationic surfactants leads to a weaker ER response in nanocomposites whose matrices have faster relaxation modes. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017

Investigation on the synergistic effect of γ-aminopropyltriethoxysilane and polyethylene-grafted glycidylmethacrylate on the properties of high-density polyethylene/poplar wood flour composites and their synergistic mechanism

Wood–plastic composites were prepared from poplar wood flour and high-density polyethylene (HDPE) by melt blending and injection molding techniques, using polyethylene-grafted glycidylmethacrylate (HDPE- g-GMA) as compatibilizer and γ-aminopropyltriethoxysilane as coupling agent. The scanning electron microscopy results showed that a stronger interfacial adhesion was formed between the wood flour and HDPE matrices during the combined use of γ-aminopropyltriethoxysilane and HDPE- g-GMA, while the X-ray photoelectron spectroscopy results showed that more HDPE chains are linked to the surface of poplar wood flour through the formation of chemical bonding in the presence of γ-aminopropyltriethoxysilane and HDPE- g-GMA. So, HDPE- g-GMA and γ-aminopropyltriethoxysilane showed a synergistic effect on the improvement of compatibility between the poplar wood flour and HDPE matrices and better mechanical properties of wood–plastic composites could be obtained. Furthermore, the thermogravimetric analysis results also indicated the synergistic effects to some extent. The synergistic mechanism of γ-aminopropyltriethoxysilane and HDPE- g-GMA was proposed on the basis of investigation results.

Synthesis and thermal properties of the MA/HDPE composites with nano-additives as form-stable PCM with improved thermal conductivity

For the purpose of improving the thermal conductivity of the form–stable phase change materials (FSPCM), two types of nano–powders with high thermal conductivity were added into the samples. In the modified FSPCM, myristic acid (MA) was used as a solid–liquid phase change material (PCM), high density polyethylene (HDPE) acted as supporting material to prevent the leakage of the melted MA. Nano–Al2O3 (NAO) and nano–graphite (NG) were the additives for thermal conductivity enhancement. Scanning electronic microscope (SEM), Fourier transformation infrared spectroscope (FT–IR) and X-ray diffractometer (XRD) were used to analyze the microstructure, chemical structure and crystalline phase of the samples, respectively. Furthermore, the specific latent heat and phase transition temperature, thermal conductivity and thermal reliability were investigated using differential scanning calorimeter (DSC), thermal conductivity meter and thermo–gravimetric analyzer (TGA). The results showed that the MA was uniformly absorbed in the HDPE matrices and there was no leakage during the melting process when the mass fraction of the MA in the MA/HDPE composite was less than 70%. The DSC results revealed that the modified FSPCM have a constant phase change temperature and high specific latent heat. The thermal conductivity of the FSPCM was measured in the solid (30°C) and liquid (60°C) states of the MA. When the mass fraction of nano–powder additives is 12%, the thermal conductivities of the FSPCM increase by 95% (NAO) and 121% (NG) at 30°C. It is anticipated that the FSPCM possess a potential application for thermal energy storage.

Effect of carbon nanotubes on thermal pyrolysis of high density polyethylene and polypropylene

The goal of this work is to analyze the effect of carbon nanotubes (CNTs) on the pyrolysis of either high density polyethylene (PE) or polypropylene (PP) matrices by using both kinetic thermogravimetric analyses (TGA) under non-isothermal conditions and a fixed-bed reactor under isothermal conditions. Under non-isothermal conditions, CNTs increased the beginning of thermodegradation for both matrices with differences as high as 30 °C and 22 °C as compared with neat PP and PE, respectively. This enhanced thermal stability in PP based composites was associated with an increase in the apparent activation energy whereas in PE based composites lower pre-exponential factors associated with reduced conformational entropy, are responsible for the enhanced thermal stability. The thermodecomposition processes were studied by assuming geometrical contraction and nucleation models. The invariant pre-exponential factor and apparent activation energy obtained were quantified for each sample confirming that these values depended on the polymer matrix and concentration of CNTs. These invariant parameters were in good agreement with those obtained by isoconversional analyses allowing the prediction of the thermogravimetric behavior. Our findings clearly showed the strong effect of CNTs on the non-isothermal pyrolysis of polymer materials changing its kinetic and the activation energy. Results from isothermal pyrolysis (450 °C-40′) confirmed the thermal stability by the presence of CNTs as higher condensable (C9–C40) and lower gas (C1–C4) yields in PP-CNTs composites, and a higher amount of unreacted polymer and a lower both condensable and gas yields for PE-CNT, as compared with the pure matrix, were found.