Multi-walled Carbon Nanotubes Content Research Articles

Dielectric Properties of Hybrid Polyethylene Composites Containing Cobalt Nanoparticles and Carbon Nanotubes.

Polymer composites with electrically conductive inclusions are intensively developed for microwave shielding applications, where lightweight and elastic coatings are necessary. In this paper, dielectric properties of hybrid polyethylene composites containing cobalt nanoparticles and multi-wall carbon nanotubes (MWCNT) were investigated in the wide frequency range of 20–40 GHz for electromagnetic shielding applications. The percolation threshold in the hybrid system is close to 6.95 wt% MWCNT and 0.56 Co wt%. Cobalt nanoparticles (up to highest investigated concentration 4.8 wt%) had no impact on the percolation threshold, and for the fixed total concentration of fillers, the complex dielectric permittivity is higher for composites with bigger MWCNT concentrations. Moreover, the microwave complex dielectric permittivity of composites with high concentration of fillers is quite high (for composites with 13.4 wt% MWCNT and 1.1 wt% Co ε′ ≈ ε″ ≈ 20 at 30 GHz, it corresponds to microwave absorption 50% of 1 mm thickness plate); therefore, these composites are suitable for electromagnetic shielding applications.

Mechanical performance of metakaolin-based geopolymer mortar blended with multi-walled carbon nanotubes

In recent decades, the cement industry has been viewed as a major environmental problem mainly due to carbon dioxide CO2 emissions during the production of Portland Cement (PC). Among the solutions to this problem is to replace Portland cement-based materials with alkali-activated materials. Metakaolin-based geopolymer mortars are currently considered a serious alternative to ordinary Portland cement mortar due to its various advantages. The present experimental study aims to develop metakaolin-based geopolymer mortars reinforced with multi-walled carbon nanotubes (MWCNTs). The content of MWCNTs incorporated was 0.1; 0.2; 0.3, and 0.4 wt%, respectively, with respect to the mass of metakaolin. A mixture without the addition of carbon nanotubes was also prepared and used as a reference (control sample). The alkaline activation of metakaolin was carried out using aqueous sodium silicate solution having a molar ratio (SiO2/Na2O) equal to 1.77. Mechanical characterization of the hardened samples was performed after curing for 3, 7 and 28 days. The results indicate that the incorporation of multi-walled carbon nanotubes in the geopolymer matrices improves compressive strength. Microscopic analysis has shown that these carbon nanotubes contribute to the densification of the geopolymer matrix and give rise to crack bridging mechanisms. The highest value of the compressive strength was recorded using an alkali silicate content equal to 8 (expressed as a percentage of Na2O) combined with 0.2% of multi-walled carbon nanotubes in the geopolymer mortar. The integral absolute error (IAE) calculated on the compressive strength values at different curing ages are all within an acceptable range (0–10%).

A lightweight polyurethane-carbon microsphere composite foam for electromagnetic shielding

Abstract In this study, we have produced a lightweight foam composite material by a simple freeze-drying method, which is composed of carboxylated multi-walled carbon nanotubes (MWCNTs), mesoporous carbon hollow microspheres (MCHMs), water-based polyurethane (WPU), and polyvinyl alcohol (PVA). MCHMs were prepared by a novel and facile method. We found that the electromagnetic shielding performance of foam composites can be adjusted by adjusting the density of foam composites, and the electromagnetic shielding performance of composites can be enhanced through the synergistic effect of hollow mesoporous carbon and MWCNTs. The composite material with a density of 232.8042 mg·cm−3 and 40 wt% MWCNT has a δ of 30.2 S·m−1 and SE of 23 dB. After adding 10 wt% MCHMs to the composite material, δ reaches 33.2 S·m−1, and SE reaches 28 dB. Both absorption losses accounted for 70%. The increase in the content of MWCNT, the increase in density, and the introduction of MCHMs all have a positive effect on the δ and SE of the composite material.

Influence of processing parameters on final characteristics of Ni-P-MWCNT coatings produced by pulsed electrodeposition

ABSTRACT The aim of the present work is to study the effects of multi-walled carbon nanotubes (MWCNT) concentration and current density on the surface morphology, microhardness, and corrosion resistance of pulsed electrodeposited Ni-P-MWCNT composite coatings. Ni-P-MWCNT composite coatings were deposited on low-carbon steel substrates using different MWCNT concentrations, namely 0.5, 1.0, and 1.5 g L−1 under various current densities of 3, 4, and 5 A dm−2. The as-produced coatings were characterised using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Vickers microhardness measurement, and electrochemical impedance spectroscopy (EIS). To determine the impact of post-heat treatment on the microstructure and microhardness of the coatings, the composite coatings were heat-treated at 400°C for 1 h. Change in the studied variables profoundly altered the final characteristics of the Ni-P deposits. While the incorporation of 1.0 g L−1 MWCNT enhanced the microhardness of the alloy deposit by 560 HV, the microhardness of the composite coating was further increased by 405 HV when it underwent post deposition-heat treatment. The corrosion resistance of the composite coating is about 4 times higher than that of alloy deposits. The optimum mechano-corrosion results were obtained for Ni-P-1.0 g L−1 MWCNT coating fabricated under current density of 4 A dm−2.

Hybrid Nanofluid in a Direct Absorption Solar Collector: Magnetite vs. Carbon Nanotubes Compete for Thermal Performance

The paper presents the experimental measurements of thermal efficiency of a tubular direct absorption solar collector (DASC) with a hybrid nanofluid based on magnetite (Fe3O4) and multi-walled carbon nanotubes (MWCNT). The volumetric concentration of Fe3O4 and MWCNT was 0.0053% and 0.0045%, respectively. The experiments were carried out for the flow rates of 2–10 L/min and a temperature difference up to 20 ∘C between the environment and the DASC. The performance of the DASC with a hybrid nanofluid was in the range of 52.3–69.4%, which was just beyond the performance of the collector with surface absorption. It was also found that using a MWCNT-based nanofluid with an equivalent total volumetric concentration of particles (0.0091%), the efficiency was 8.3–31.5% higher than for the cases with the hybrid nanofluid.

A composite material with controllable electromagnetic characteristics for the terahertz frequency range

In this study, a new method is proposed for producing polymer composites via the adsorption of multiwalled carbon nanotubes (MWCNTs) on the surface of polystyrene spheres (PS) to provide a cellular distribution of MWCNTs in the composite. The method makes it possible to control the cell size down to the submicron level and the conductivity of the composite in a wide range. The effect of the MWCNT concentration on the surface of PS on the structure of the resulting composites and their electrophysical properties are studied in the frequency range of 115 GHz–1.4 THz. The percolation nature of the composite conductivity was established. It was shown that the obtained composite is a regularly chaotic medium, and its regularity scale corresponds to the sizes of the PS. MWCNTs on the PS surface form two subsystems: the first is a pseudo-regular subsystem on the edges of cuboid-like PS, while the second subsystem consists of chaotically scattered MWCNTs with unclosed ends on the faces of PS. The first subsystem belongs to the regular part of the structure and mainly determines the properties of the medium at frequencies above 500 GHz. The second subsystem of nanotubes is characterized by a small electrodynamic scale comparable with the size of one PS cell and determines the effective properties of the composites at frequencies below 500 GHz.

Electrochemical performance of TiNb2O7 nanoparticles anchored with different contents of MWCNTs as anode materials for Li-ion batteries

In this study, the electrochemical behavior of titanium niobium oxide (TNO) composites with 1, 3, and 5 wt% of multi-walled carbon nanotubes (MWCNTs) was investigated. The results showed a significant improvement in the electrochemical performance of TNO by the addition of MWCNTs in terms of initial capacity, rate performance, and rate capability. The initial capacity of pure TNO at 0.1C increased from 251.6 mAh/g to 272.4, 302.2, and 265.9 mAh/g by addition of 1, 3, and 5 wt% of MWCNTs, respectively. Furthermore, the cyclic stability of the samples improved considerably by the addition of the MWCNTs; the capacity value of pure TNO after 200 cycling at 1C was only 78.3 mAh/g while for TNO/3 wt% MWCNTs was about 145.6 mAh/g. Similarly, the rate performance of the TNO/MWCNTs nanocomposites was better than pure TNO in all charge/discharge rates. The MWCNTs contents in nanocomposites had significant effects on their performance in which the optimal content of MWCNTs in this study was 3 wt%. The results showed that the presence of MWCNTs in nanocomposites created a conductive network with good ionic and electrical conductivity and thus, improved the rate performance of samples. In addition, the stresses caused by the intercalation/deintercalation of Li-ions were moderated by MWCNTs, improving the cyclic stability.

The fabrication and testing of a self-sensing MWCNT nanocomposite sensor for oil leak detection

Abstract Oil spillage, due to either direct or indirect accidents, can cause major environmental and economic issues if not detected and remedied immediately. In this study, the unique properties of carbon nanotubes have shown a substantial sensing capability for such a purpose when incorporated into a nanostructured composite material. A high-efficiency self-sensing nanocomposite sensor was fabricated by inserting highly conductive multi-walled carbon nanotubes (MWCNTs) into an elastomeric polymer substrate. The microstructure of the nanocomposite sensor was studied using scanning electronic microscopy and Raman spectroscopy. The response rate of the sensor was evaluated against different MWCNT concentrations, geometrical thickness and applied strains (causing by stretching). The results indicated that the response rate of the sensor (β) decreased with increasing MWCNT concentration and showed the strongest response when the sensor contained a 1.0 wt % concentration of MWCNTs. Additionally, it was found that the response time of the self-sensing nanocomposite sensors decreased in keeping with decreases in the sensor thickness. Moreover, when the sensor was subjected to strain, while immersed in an oil bath, it was found that the response rate (β) of the unstretched self-sensing nanocomposite sensor was significantly lower than that of the stretched one. The sensors given a 3% applied strain presented a response rate (β) ≈ 7.91 times higher than of the unstretched one. The self-sensing nanocomposite sensor described here shows good potential to be employed for oil leakage detection purposes due to its effective self-damage sensing capability and high sensing efficiency and low power consumption.

Developing sustainable Zn-MWCNTs composite coatings using electrochemical co-deposition method: Tribological and surface wetting behavior

ABSTRACT Carbon nanotube (CNT) nanofillers are a part of carbon allotrope family materials with numerous and effective features. Multiple CNTs nested one another is a low-cost and scalable category of CNTs, known as multi-walled CNTs (MWCNTs), which are well-stablised for their excellent mechanical, electrical and thermal properties. In this present work, MWCNTs nanofiller embedded Zn matrix (Zn-MWCNTs) composite coatings were fabricated by adding the different concentrations of MWCNTs (0.5, 0.1 and 0.2 g/L) in the acidic electrolyte bath using electrochemical co-deposition route with uniform embedment. The prepared composite coatings were characterised using advanced characterisation techniques (XRD, FESEM and EDS) for their obtained surface morphology and microstructures. All Zn-MWCNTs composite coatings exhibited enhanced tribo-mechanical performance compared to pure Zn coatings. Zn-MWCNT (0.2 g/L) composite coating exhibited the highest average microhardness value of 119 HV and minimum wear rate of 12.5 × 10−3 mm3N−1m−1 among all the prepared composite coatings, which attributed to the synergistic effect of microstructural refinement and superior mechanical properties of MWCNTs. Surface wetting studies reveal that MWCNTs play an important role in increasing hydrophobicity in terms of contact angle, which increased by 1.93 times for Zn-MWCNT (0.2 g/L) composite coating. The present work may be helpful for facile fabrication of low-cost biocidal Zn-MWCNTs nanocomposite coating.

Effect of dry milling and MWCNTs content during fabrication of Fe-MWCNTs metal matrix composite by high energy planetary milling followed by conventional sintering

The present paper discusses about fabrication of iron-based composite using multi walled carbon nanotubes (MWCNTs) as reinforcing agent by using high energy planetary milling followed by conventional sintering. Composites containing iron and 0.5, 1.0, 2.0 and 4.0 vol. % MWCNTs powder mixtures are milled in dry (argon atmosphere) condition for 10 h in a dual drive planetary mill (DDPM). It has been observed that after 10 h of milling, average particle size decreases from 36 to 10 µm. The field emission-scanning electron microscopy (FESEM) images show that final powder is spherical in shape after milling. Raman spectroscopy reveals distortion and formation of defects in MWCNTs after 10 h of milling and MWCNTs are stable upto 900 °C and losses stability when consolidated at both 1200 and 1300 °C. The maximum value of relative density and hardness are 88 % and 252 VHN respectively for the Fe-0.5 vol. % MWCNT composite sintered at 1300 °C for 2 h. The maximum value of yield strength and compressive strength are also achieved for Fe-0.5 vol. % MWCNTs composite sintered at 1300 °C and the values are 350 MPa and 580 MPa respectively.

Development of emphatic catalysts for waste water remediation via synchronized free radical and non-free radical routes with composites of strontium hexaferrite, graphene and multi-walled carbon nanotubes

Magnetic nanoparticles have shown exceptional potential in catalysis, however, their tendency to agglomerate has confined their use. The present work encompasses synthesis of eco-friendly and magnetic retrievable catalysts with different fractions of reduced graphene oxide (rGO) and multiwalled carbon nanotubes (MWCNT) as support for strontium hexaferrite (SrFe12O19) for the oxidative degradation of organic pollutants. The morphological, structural and magnetic properties of composites were estimated via PXRD, FT-IR, VSM, FE-SEM, HR-TEM, XPS and BET. The crystallite size decreased from 41.46 nm for SrFe12O19 to 35.85 nm and 33 nm for composites with 20% rGO and MWCNTs, respectively while the surface area increased substantially from 88.1 m2/g for SrFe12O19 to 118.4 and 131.3 m2/g. Further, the composites were employed as catalysts for the oxidative degradation of selected antibiotics and colourant via stimulation of two different oxidants, potassium peroxymonosulphate (PMS) and hydrogen peroxide (H2O2). The degradation followed pseudo first order kinetics with rate constant values increasing with rGO and MWCNT content. The increase in catalyst effectiveness can be ascribed to the synergistic interactions between rGO or MWCNT and SrFe12O19, which provided larger specific surface areas for adsorption and augmented number of catalytically active sites. Systematic chemical quenching studies unveiled a combined role of radical and non-radical species in oxidative degradation of pollutants. Moreover, the synthesized composites exhibited excellent recyclability upto four cycles forming the basis for their utilization as industrial catalysts.

Fabrication and mechanical properties of multi-walled carbon nanotubes doped AlN ceramics prepared by spark plasma sintering

In this study, multi-walled carbon nanotubes (MWCNTs) are uniformly dispersed in aluminium nitride (AlN) powders, and the MWCNTs-doped AlN ceramics are sintered at 1500 °C with a holding time of 5 min by spark plasma sintering using Y 2 O 3 as the sintering additive. The effects of the MWCNTs content on the microstructure and mechanical properties of the as-obtained ceramic composites are investigated. The results reveal that many submicron pores are generated when protecting the structure of the CNTs, thereby reducing the density of the AlN ceramic. However, the gradual filling of the grain gap may compensate for the strengthening after CNT doping. The relative density and hardness reach the maximum values of 89.6% of the theoretical density and 7.0 ± 0.3 GPa, respectively, at the doping amount of 2.5 wt%.

Electrochemical Water Splitting Using NiO-NiFe2O4/MWCNTs Nanocomposite as Electrocatalyst

Escalating energy demands, scarcity of conventional energy resources and environmental concerns are the key to fuel production through water splitting. Various electrocatalysts have been reported, considering the cost effectiveness, stability and OER (oxygen evolution reaction) activity. In the same context, porous hybrid NiO-NiFe2O4/MWCNTs based nanocomposite as an OER electrocatalyst, has been investigated in the current study. The synthesis has been accomplished via co-precipitation using Tween as a surfactant. Characterization and electrochemical study for water electrolysis using synthesized electrocatalyst deposited glassy Carbon (GC) electrode as anode was carried out using relevant tools. Iron-doped Nickel oxide nanoparticles were synthesized recognizing excellent oxygen evolution activity of NiO and its increase in conductivity with Fe incorporation due to its higher electropositivity. Nanocomposites were synthesized by incorporating upto 20% weight percent MWCNT (Multiwall carbon nanotubes). High surface to volume ratios, stability and excellent conductivity of MWCNTs furthermore, reduction of crystallite sized due to their incorporation enhanced the performance of the electrocatalyst significantly. Hybrid formation of NiO and NiFe2O4 at a certain calcination temperature was also found to be the reason for enhanced OER activity due to the increased grain boundaries. Porous NiO-NiFe2O4/MWCNTs with 10% MWCNTs concentration outperformed with 35mA/cm2 of current density at 1.8V in alkaline media.

An innovated method to monitor the health condition of the thermoelectric cooling system using nanocomposite‐based CNTs

Many crucial applications use the thermoelectric coolers (TECs) system because they have some desirable properties, including durability, reliability, simple structure, and quietness. However, the performance of TECs is sensitive to any form of change and needs to be monitored constantly to ensure that they are working at their optimal. This paper proposes a novel approach for condition monitoring. This novel approach, unlike other attempts, does not need additional sensors but is directly carried out through the exploitation of the multi-wall carbon nanotubes (MWCNTs) piezoresistive property. For the suggested approach, a polyurethane (PU) resin was altered using various MWCNTs concentrations with the aim of constructing self-sensing nanocomposites sensors whose electrical conductivity is high. To investigate the electrical properties and microstructure of the constructed sensor, electrical resistance measurement, and scanning electron microscopy were used. From the results, it can be concluded that as the thickness increased, conductivity exhibited a monotonic increase. The peak electrical conductivity was 2.55 S.cm−1 for the 3.1 mm-thick MWCNTs sensors. This is approximately 5.1 above that of the 0.6 mm-thick MWCNTs sensors. Added to this, the MWCNT/PU sensors exhibited a high-temperature sensitivity with a negative temperature coefficient of resistance. The normalised resistance obtained from the sensor with the uppermost MWCNTs concentration is lower in comparison to the sensors with lower concentrations of MWCNTs. Additionally, the TEC cooling temperature influence on the tunnelling distance between MWCNTs was analytically estimated. This study's numerical results indicate that there is a potential correlation between TEC cooling generated temperature and the variations noted in the tunnelling distance between MWCNTs with an explicit impact on the general nanocomposite sensors changes in electric resistance when the TEC system is in service.

Preparation and optimization of polyurethane/crosslinked poly acrylic acid semi-IPNs containing multi wall carbon nanotube applicable for artificial tendon

The tendons and nerves of the body are inextricably linked to each other. That is why the adjacent neural system should also be supported in the most effective treatments for damaged tendons. Hence in designing the tissue engineering tendons, adequate elasticity, good biocompatibility, and relative conductivity must be achieved to stimulate nerve tissue. This study aims to prepare semi-interpenetrating polymer networks (semi-IPNs) based on polyurethane (PU)/crosslinked polyacrylic acid (PAA), using Response Surface Methodology (RSM). Concerning this method, the variables such as the amount of AA, crosslinker, and multi-wall carbon nanotube (MWCNT) were optimized. Notably, the swelling, mechanical strength, tensile strength, and electrical conductivity of the prepared composites were selected as the evaluated responses. The optimal samples had an AA content of 20 wt%, a crosslinking agent of 8.75 and 16.25 mol.%, and an MWCNT content of 1 and 3 wt% Optimal samples were then evaluated by X-ray diffraction analysis (XRD), cyclic mechanical strength, electrical conductivity, biocompatibility and cell adhesion. The promising results of these evaluations demonstrated that the PU/PAA/MWCNT semi-IPN nanocomposites could be a proper biocompatible material for artificial tendons.

Impact of Multi-Walled CNT Incorporation on Dielectric Properties of PVDF-BaTiO3 Nanocomposites and Their Energy Harvesting Possibilities

The current study investigated the fabrication of multi-walled carbon nanotubes (MWCNTs) adhering to Barium titanate (BaTiO3) nanoparticles and poly(vinylidene fluoride) (PVDF) nanocomposites, as well as the impact of MWCNT on the PVDF-BaTiO3 matrix in terms of dielectric constant and dielectric loss with a view to develop a high performance piezoelectric energy harvester in future. The capacity and potential of as-prepared nanocomposite films for the fabrication of high-performance flexible piezoelectric nanogenerator (PNG) were also investigated in this work. In particular, five distinct types of nanocomposites and films were synthesized: PB (bare PVDF–BaTiO3), PBC-1 (PVDF–BaTiO3-0.1 wt% CNT), PBC-2 (PVDF–BaTiO3-0.3 wt% CNT), PBC-3 (PVDF–BaTiO3-0.5 wt% CNT), and PBC-4 (PVDF–BaTiO3-1 wt% CNT). The dielectric constant and dielectric loss increased as MWCNT concentration increased. Sample PBC-3 had the optimum dielectric characteristics of all the as-prepared samples, with the maximum output voltage and current of 4.4 V and 0.66 μA, respectively, with an applied force of ~2N. Fine-tuning the BaTiO3 content and thickness of the PNGs is likely to increase the harvester’s performance even more. It is anticipated that the work would make it easier to fabricate high-performance piezoelectric films and would be a suitable choice for creating high-performance PNG.

Preparation and characterization of multi-walled carbon nanotubes-filled cotton fabrics

Herein we report the preparation and characterization of conductive cotton fabric prepared by a one-step simple method; drop casting and drying, using different weight concentrations of multi walled carbon nanotubes (MWCNTs) dispersed in dimethylformamide (DMF). The conductive MWCNTs cotton fabrics were characterized with different chemical and physical techniques to explore their structure, morphological features and the electrical properties by measuring the sheet resistance. The changes in sheet resistance of the conductive MWCNTs cotton fabrics were monitored as a function of MWCNTs concentration and temperature, and low sheet resistance of 15.92 Ω/sq could be achieved and the conductive MWCNTs cotton fabrics showed semiconductor behavior. Also, it was observed that the sheet resistance significantly decreased with increasing the MWCNTs concentration (sheet resistant α [MWCNTs]−1.5). A simulation study suggested that this behavior was explained by nearest neighbor interaction between the particles of MWCNTs.

Thermoelectric and Photothermoelectric Properties of Nanocomposite Films Based on Polybenzimidazole and Carbon Nanotubes

We herein report the thermoelectric and photothermoelectric properties of polybenzimidazole (PBI)-based nanocomposite films with 1–20 wt % multiwalled carbon nanotube (MWCNT) loadings, which are manufactured by a facile solution casting method. The thermoelectric characterization, which is carried out at temperature differences of up to 40 K between both film ends, reveals that the Seebeck coefficient of the nanocomposite films increases from ∼29 to ∼36 μV/K with increasing MWCNT content from 1 to 20 wt % and that the thermoelectric current generation efficiency changes from ∼1 nA/K at 1 wt % MWCNT to ∼84 nA/K at 10 wt % MWCNT to ∼28 nA/K at 20 wt % MWCNT. The visible light illumination at the interface between the nanocomposite film and the silver electrode induces excellent photothermoelectric performance in terms of temperature increment (ΔTPT), voltage generation (VPTE), and electric current generation (APTE), which are dependent on the MWCNT content and visible light wavelength. For instance, the PBI nanocomposite film with 10 wt % MWCNT can attain ΔTPT of ∼33 °C, VPTE of ∼267 μV, and APTE of ∼234 nA under the visible light illumination of 520 nm wavelength and 8.87 W/cm2 power density at the interface between the film and the electrode. This excellent photothermoelectric performance of PBI/MWCNT nanocomposite films enables potential materials for advanced applications of energy harvesting and sensing from visible light and heat.

A study on mechanical properties and thermal properties of UHMWPE/MWCNT composite fiber with MWCNT content and draw ratio

In this study, the mechanical properties and thermal properties of ultra-high molecular weight polyethylene (UHMWPE)/multi wall carbon nanotubes (MWCNT) composite fiber were investigated with different weight percent of the MWCNT contents and draw ratio. To verified the thermal properties of the MWCNT/UHMWPE composite fiber, DSC and TGA analysis were performed. The addition of MWCNT and the higher draw ratio improved the thermal properties of the UHMWPE composite fiber by improving the crystallinity of the polymer. By adding 2 wt% MWCNT, UHWMPE fibers with tensile strengths of 3.85 GPa and young’s modulus of 27.43 GPa could fabricated. In comparison with the pristine UHMWPE fiber with same draw ratio conditions, there values shows increases of 21% in tensile strength and 16% in young’s modulus value. However, in the case of the specimens in which the MWCNT content of 6wt% and 10wt% was added to the UHMWPE fiber, the tensile strength and tensile modulus gradually decreased. We proved by experimentally that the mechanism of strengthening the tensile strength of UHMWPE fibers with MWCNT content of 2wt% is to block craze stretching and reduce defects inside the amorphous region by improving the crystalline region. However, the MWCNT contents is increased by 6wt% or more, the nanofillers start to agglomerate and act as impurities and stress concentration factors, thereby reducing the mechanical properties of the UHMWPE composite fiber.

ADDITIVE MANUFACTURING OF SURLYN SPECIMENS WITH A NANO-REINFORCEMENT OF CARBON NANOTUBES.

This paper explores the self-healing abilty of the ionomer called Surlyn® 8940 (manufactured by DuPont), a partially neutralised poly(ethylene-co-methacrylic acid) (EMAA) ionomer copolymer, and the improvement of the mechanical properties after adding a nano-reinforcement of multiwall carbon nanotubes (MWCNTs) to the structure of the polymer. It begins with the manufacture the nanocomposite material, based on Surlyn® 8940 as raw material, and the mixture process with MWCNTs. Afterwards, an extrusion process was optimized to obtain a homogeneous reinforced filament, which was subsequently used to manufacture the final test samples by means of a 3D printing machine. Specimens with different concentrations of MWCNTs (0.0, 0.1, 0.5, 1.0 % wt.) were manufactured, in order to test the mechanical properties and self-healing ability of unreinforced and nano-reinforced samples. The results show that nano-reinforced samples had an increase of their self-healing ability (increase for 0.5 y el 1% wt. of MWCNTs) and mechanical properties (σTS 18.35, 25.91, 26.92, 28.02 MPa to 0, 0.1, 0.5 y 1 % wt. de MWCNTs respectively). Specimens of 5% of MWCNTs have also been manufactured with different mixing times in the extrusion chamber to study the conductivity of the polymer. Electrical conductivity values ​​for 8 and 10 minutes of mixing times reached S/m units order have been obtained.