Incorporation Of Carbon Nanotubes Research Articles

Performance optimization of non-fullerene acceptor organic solar cell by incorporating carbon nanotubes as flexible transparent electrode

The Power Conversion Efficiency (PCE) of an Organic Solar Cell (OSC) is largely determined by the Transparent Conductive Electrode (TCE). ITO, the most commonly used TCE, degrades the device performance on flexible plastic substrate due to its brittleness and formation of cracks under mechanical stress. As a result, an alternative TCE is required to optimize OSC output. Owing to their high optical transparency, low sheet resistance, and high mobility, carbon nanotubes have gotten a huge interest as an electrode in organic solar cells. The present work uses the software SCAPS 1-D to simulate the performance of the NFA-BHJ-OSC with a transparent electrode of Carbon nanotubes doped with Molybdenum trioxide (MoO3). The optimized PCE of 22.71 %, Fill Factor (FF) of 63.14 %, Jsc of 38.38 mA/cm2 and Voc of 0.9371 V are shown in the current simulation-based work by varying the band gap of MoO3 doped CNTs. Also, upgrading the simulated cell's hole transport Layer with CuI, Cu2O, and CuSCN HTLs yields an optimizedresult with CuSCN HTL, having PCE of 27.57 %, FF of 70.88 %, Jsc of 37.12 mA/cm2, and Voc of 1.0477 V. These results show that BHJ-OSCs using CNT as a TCE hold promise to elevate the device performance of OSC in the near future.

Non-Isothermal Crystallization Kinetics of Polyether-Ether-Ketone Nanocomposites and Analysis of the Mechanical and Electrical Conductivity Performance.

High-performance polyether-ether-ketone (PEEK) is highly desirable for a plethora of engineering applications. The incorporation of conductive carbon nanotubes (CNTs) into PEEK can impart electrical conductivity to the otherwise non-conductive matrix, which can further expand the application realm for PEEK composites. However, a number of physical properties, which are central to the functionalities of the composite, are affected by the complex interplay of the crystallinity and presence of the nanofillers, such as CNTs. It is therefore of paramount importance to conduct an in-depth investigation to identify the process that optimizes the mechanical and electrical performance. In this work, PEEK/CNTs composites with different carbon nanotubes (CNTs) content ranging from 0.5 to 10.0 wt% are prepared by a parallel twin-screw extruder. The effects of CNTs content and annealing treatment on the crystallization behavior, mechanical properties and electrical conductivity of the PEEK/CNTs composites are investigated in detail. A non-isothermal crystallization kinetics test reveals a substantial loss in the composites' crystallinity with the increased CNTs content. On the other hand, mechanical tests show that with 5.0 wt% CNTs content, the tensile strength reaches a maximum at 118.2 MPa, which amounts to a rise of 30.3% compared with the neat PEEK sample after annealing treatment. However, additional annealing treatment decreases the electrical conductivity as well as EMI shielding performance. Such a decrease is mainly attributed to the relatively small crystal size of PEEK, which excludes the conductive fillers to the boundaries and disrupts the otherwise conductive networks.

Coating Properties of Alkyd Resin, Epoxy Resins and Polyurethane Based Nanocomposites: A Review

The uniqueness of alkyd resin, epoxy resin, and polyurethane nanocomposites has brought prominent recognition to the field of heavy-duty coating materials. This is expected due to the collaborative features of nano-sized materials such as the high surface area to volume ratio, great functionality per-unit space, extremely small sizes with high density, and that of alkyd resin, epoxy resin, and polyurethane (biodegradability, great gloss retention, adaptability, flexibility, durability, good drying properties, and weathering resistance). The objective of this review was to analyze the extent and currency of research and the development of alkyd, epoxy, and polyurethane nanocomposites in coating applications. Some of the several types of modifications discussed in this review are the incorporation of varying types of nanoclay and metal nanoparticles materials into alkyd resins, the incorporation of carbon nanotubes, MGel-graphene oxide (GO)/gelatin (MGel), Ni (II) Complex-Zeolite and starch-modified nano-ZnO into epoxy resin and the incorporation of (Rb2Co(H2P2O7)2.2H2O), modified nanoparticles of ZnO, diminished graphene oxide (dGO) into polyurethane and their effects on coating applications. The various studied modifications resulted in nanocomposite end-products with much improved properties. However, there are several challenges to the development of nanocomposites that need urgent attention. Some of the challenges discussed are the difficulty involved in transforming fabricated nanocomposites from laboratory to commercialized scale, the capital-intensive nature of synthesizing large nanopowder, etc.

Ferric Ions Crosslinked Epoxidized Natural Rubber Filled with Carbon Nanotubes and Conductive Carbon Black Hybrid Fillers.

Natural rubber with 50 mol % epoxidation (ENR-50) was filled with carbon nanotubes (CNTs) and conductive carbon black (CCB) hybrid fillers with various CCB loadings of 2.5, 5.0, 7.0, 10.0 and 15.0 phr, and the compounds were mixed with ferric ion (Fe3+) as a crosslinking agent. The ENRs filled exclusively with CNTs, and CNT–CCB hybrid fillers exhibited typical curing curves at different CCB loadings, i.e., increasing torque with time and thus crosslinked networks. Furthermore, the incorporation of CNT–CCB hybrid fillers and increasing CCB loadings caused an enhancement of tensile properties (modulus and tensile strength) and crosslink densities, which are indicated by the increasing torque difference and the crosslink densities. The crosslink densities are determined by swelling and temperature scanning stress relaxation (TSSR). Increasing CCB loadings also caused a significant improvement in bound rubber content, filler–rubber interactions, thermal resistance, glass transition temperature (Tg) and electrical conductivity. A combination of 7 phr CNT and CCB with loading higher than 2.5 phr gave superior properties to ENR vulcanizates. Furthermore, the secondary CCB filler contributes to the improvement of CNT dispersion in the ENR matrix by networking the CNT capsules and forming CNT–CCB–CNT pathways and thus strong CNT–CCB networks, indicating the improvement in the tensile properties, bound rubber content and dynamic properties of the ENR composites. Moreover, higher electrical conductivity with a comparatively low percolation threshold of the hybrid composites was found as compared to the ENR filled with CNTs without CCB composite. The superior mechanical and other properties are due to the finer dispersion and even distribution of CNT–CCB hybrid fillers in the ENR matrix.

Effect of SW-CNT Diameter on Polymer Degradation and Resistance of Polystyrene/SW-CNTs Composites Induced by γ-Irradiation

The outstanding electrical, mechanical, and thermal properties of carbon nanotubes (CNTs) make them promising materials for a wide range of applications. Numerous theoretical and experimental studies on the diameter-dependent properties of single-walled carbon nanotubes (SW-CNTs) exist. The incorporation of carbon nanotubes into commercial polymers can alter the properties of both materials. Herein, we demonstrate polystyrene/SW-CNT composites with different diameters to check property changes, including radiation-protective characteristics under various doses of gamma radiation. The intrinsic glassy state of polystyrene disappeared owing to the introduction of SW-CNTs into the polymer-polymer chain. In addition, when 1.3 nm diameter SW-CNTs were introduced, the Fourier-transform infrared spectroscopy peaks for alkyl aryl ethers were observed at 10–60 kGy of gamma irradiation. In this study, the different phenomena that occur when polystyrene/SW-CNT composites are formed with different SW-CNT diameters (0.78 nm and 1.3 nm) were investigated via systematic analyses.

(Digital Presentation) Evaluating the Performance of Multi-Walled Carbon Nanotube Composite Microporous Layers Deposited on Carbon Felt Gas Diffusion Layers

Electrochemical energy storage devices (EESDs) such as metal-air batteries (MABs) and alkaline electrolyte membrane fuel cells (AEMFCs) have begun to gain vast amounts of attention due to their high theoretical energy densities and open-circuit voltage values. Although these devices present promising aspects for the environment and sustainability, they suffer from the slow reaction kinetics and degradation effects that occur at the catalyst layer interface of the air electrode. Typically, these effects are due to the accumulation of molecular species such as water or oxygen at catalyst active sites because of poor electrode hydrophobicity and fluid management. Herein, we perform experimentation to mitigate these effects by implementing mixed carbon composite microporous layers onto porous carbon felt based air electrodes. This adaptation of the air cathode was predominantly based on the aforementioned downfalls and the lack of availability of commercial carbon felts that have adequate wet proofing and conductivity like some of the related carbon paper gas diffusion layers. Microporous layers (MPLs) enhance electrical conductivity, surface area, and adhesion at the catalyst layer and gas diffusion layer interface. These layers typically consist of a hydrophobic polymer such as polytetrafluoroethylene (PTFE) and a conductive carbon black substrate such as Ketjen Black 600JD (KJB). The incorporation of multi-walled carbon nanotube (MWCNT) and carbon black composites into the structure of the MPLs drastically decreases ohmic polarization with minimal increases in specific resistance. The electrical resistance of the synthesized carbon substrate decreases at high rates of MWCNT dispersion, which corresponds directly to a low MWCNT weight percentage within the composite. The MPL increases the mass transport through the electrode by mitigating flooding effects that typically occur within the pores near the surface of the catalyst layer, ultimately aiding in charge transfer between the gas diffusion layer and catalyst active sites. Preliminary data from AEMFC symmetric cell tests suggests that a microporous layer consisting of a 10 wt.% MWCNT/KJB (m/m) substrate is the optimal loading of carbon nanotubes and leads to better cell performance. There is an increase in current density of 60 mA/cm2 compared to an air electrode with no MPL within the ohmic region of the polarization curve corresponding to approximately 0.7 V, while only an increase of 18 mA/cm2 is seen for an MPL consisting of a 30 wt.% MWCNT/KJB (m/m) carbon substrate. The increase of charge transfer by the 10 wt.% synthesized carbon substrate MPL was attributed to the ability of the nanotubes at high rates of dispersion to act as molecular wires within the electrode. Additionally, zinc-air battery tests using the optimally configured air electrode, determined from previous experiments, show that the current density at an operating voltage of 1.1 V was increased by 2.3 times that of an electrode without an MPL using the same catalyst material and loading. Significantly, this research will lead to a better understanding of optimization of the air electrode used within electrochemical devices and how to eliminate some of the adverse effects associated with it. Figure 1

Test and Detection of Antifreezing and Anticorrosion Performance of Carbon Nanofiber Bridge Concrete.

In order to solve the problems of carbon nanotubes, steel fibers, and carbon nanotubes + steel fibers on the compressive strength and impact resistance of concrete, the author proposes a test method for the frost resistance and corrosion resistance of carbon nanofiber bridge concrete. Using carbon nanotubes and steel fibers as reinforcing materials, the effects of carbon nanotubes and steel fibers on the compressive strength and impact resistance of concrete were studied. Experimental results show that incorporating carbon nanotubes and steel fibers can improve the compressive strength of concrete. Compared with the single-doped carbon nanotubes, the single-doped steel fiber has a greater effect on the improvement of the impact resistance of the concrete. The toughness and ductility of carbon nanotubes and steel fiber reinforced concrete are improved again compared with that of single steel fiber reinforced concrete. The effect of adding 1% steel fiber +0.30% carbon nanotubes is the most significant in enhancing the performance of concrete. Conclusion. The synergistic effect of carbon nanotubes and steel fibers is more conducive in complementing each other's advantages and improving the performance of concrete.

Repair of delamination-cracks in CFRP using CNT-containing resin pre-coating solution through capillary action

Edge-delamination of carbon fiber reinforced plastics (CFRP) has been successfully repaired using a novel technique named resin pre-coating (RPC). The acetone-diluted resin does not only adhere to the surface but penetrates deeply into sub-surfaces through capillary action. In the current study, Carbon Nanotube (CNT) was tentatively added into RPC to further strengthen the bonding. DSC analysis and FTIR results showed no chemical effect on resin curing through adding CNT. Likewise, using CNT as additives has not changed the surface properties of RPC solution with 5 wt% resin and 95 wt% acetone. Compressive testing was performed to validate the effect of CNT incorporation (with four concentrations: 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%) on RPC repair. The results show that the 5% RPC solution mixing 1.5 wt% of CNT works best with a 22% increase over only RPC in repair effectiveness. SEM revealed CNT bridging at the fracture surface of the RPC/CNT-repaired sample.

Preparation of Modified Carbon Nanotube Polyvinylidene Fluoride Composite Film and Its Application in Packaging Design

Sustainable design does not emphasize the safety of the ecosystem, but builds a systematic innovation process, taking into account customer needs, environmental benefits, social benefits, and corporate development. This article is based on the preparation of a modified carbon nanotube polyvinylidene fluoride composite film to analyze its application value in packaging design, aiming at analyzing the performance of the modified carbon nanotube and the polyvinylidene fluoride composite film during the preparation process, and applying its various characteristics to the process of packaging design optimization concept. The article is mainly divided into two parts: preparing modified carbon nanotubes and preparing polyvinylidene fluoride composite films. Among them, the photomechanical properties of carbon nanotubes, the relationship between the composition of the composite material and the dielectric properties, the dielectric response and relaxation behavior, the hydrophilicity of the composite membrane, and the membrane separation technology were discussed, and the carbon nanotubes were constructed. Incorporating carbon nanotubes into carbon fiber hybrid materials, and combining carbon nanotubes with polymer materials, works extremely well. The structure model is prepared, the molecular pore size, hydrophilicity, etc. are recorded, and surface modification, chemical modification, blending modification, and other methods are applied to analyze and evaluate the data. The experimental results show that in the application of modified carbon nanotubes and polyvinylidene fluoride composite films and packaging design, the interactive function of toughening modification increases 2.44 points; through enhancement modification, packaging design reduction increases by 2.5 points; and through the compatibilization modification, the functionality of the packaging design has increased by 1.88 points.

Enhancing aging resistance of glass fiber/epoxy composites using carbon nanotubes

An experimental investigation is carried out to examine the effectiveness of carbon nanotubes (CNT) in minimizing the environmental assisted degradation of glass fiber/epoxy composites (GFRP). To this end, CNT modified epoxy is used to fabricate glass fiber/epoxy hybrid composites (CNTGFRP). Experimental results show that the addition of 1 wt% of CNT in conventional GFRP increases the interlaminar shear strength (ILSS) by 36% and decreases the volumetric electrical resistance by 46%. Effect of environmental factors is studied by exposing composite samples to 500 h of accelerated weathering cycle. The exposure to aging cycle not only changes the colour and microstructure, it also increases the ILSS and electrical resistance of GFRP and CNTGFRP composite samples. These changes are primarily attributed to the loss of polymer matrix and improved crosslinking in composites caused by moisture, temperature and UV rays during the aging process. It is recorded that while the deformation in unaged composites is of ductile nature, the aged samples show fiber dominated brittle behavior. Finally, it is shown that the incorporation of CNT in the matrix not only ensures structural integrity but also reduces environmental assisted degradation of conventional glass fiber/epoxy composites.

A micromechanical study of the fatigue behavior of MWCNT-modified carbon fibers/epoxy resin single filament composites subjected to cyclic loadings

This paper presents a comprehensive study on the impact of surface modification of carbon fibers using multiple-walled carbon nanotubes (MWCNTs) to improve the load-transfer capacity of the fiber-matrix interface of an epoxy matrix composite subjected to dynamic loads. The single-fiber fragmentation technique (SFFT) was utilized to characterize the length of interfase damage (IDL) produced by quasi-static and dynamic loadings for linear elastic and plastic strains and the residual efficiency of interfacial stress transfer. A finite element model was used to validate the optical measurement and the extent of interfase damage. Scanning electron microscopy (SEM) corroborated the presence of the MWCNTs on the surface of the carbon fibers. The interfacial shear strength (IFSS) increased by approximately 27.5%, attributed to the carbon nanotubes and a more significant fiber-matrix stress transfer. The application of dynamic loads decreased the mechanical properties of the matrix, premature fragmentation of the carbon fiber, and interfacial damage, which led to a reduction in the interfase load-transfer capacity. However, the incorporation of carbon nanotubes in the interface decreased the adverse effects generated by the application of cyclic loads, mainly the propagation of interfacial damage.

Evaluation of CNTs and SiC Whiskers Effect on the Rheology and Mechanical Performance of Metakaolin-Based Geopolymers

Despite geopolymers having emerged as a more sustainable alternative to Portland cement, their rheological properties still need to be thoroughly investigated, aiming at the material’s applicability. Additionally, studies that evaluated the fresh state of geopolymer composites with nanomaterials are scarce. Thus, two metakaolin-based geopolymer systems were reinforced with nanomaterials with a similar geometry: carbon nanotubes (CNT) and silicon carbide whiskers (SCW). The nanomaterials incorporation was assessed by rotational rheometry (conducted up to 110 min), isothermal calorimetry, compressive strength after 7 and 28 days, and the microstructure was investigated using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). CNT and SCW incorporation (0.20 wt.%) did not significantly affect the yield stress and viscosity of the R2-group (based on metakaolin type 2), while increasing the rheological parameters up to 56.0% for the R1-group (based on metakaolin type 1). Both additions modified the reaction kinetics. Increments of up to 40.7% were observed in the compressive strength of geopolymer pastes with the incorporation of a SCW content of 0.2 wt.%. XRD and FTIR results suggest similar structural modifications between precursors. Nevertheless, R2 showed substantial transformations while the R1 group exhibited anhydrous material that can react over time. Overall, incorporating CNT and SCW contributed to higher mechanical increments on systems with average mechanical strength (R1) compared to systems with higher potential mechanical performance (R2).

Carbon Nanotube Coatings’ Role in Transparency, Mechanical Hardness, and Wetting Angle Increase

Among the different nanostructures involved in the improvement of material properties, carbon nanotubes occupy a specific place because of their small refractive index, extended surface, and large Young’s module, which can all provoke dramatic change in basic matrix material characteristics. Inorganic crystals, semiconductors, metals, conductive compounds, and some polymer structures whose surfaces are treated with carbon nanotubes demonstrate better features than the ones obtained before carbon nanotubes deposition. Thus, the areas of application for these unique nanostructure materials can be effectively extended, e.g., for optoelectronic use, in biomedicine, and display applications. In the current paper, the advantages of the laser-oriented deposition technique are shown in order to demonstrate how the main material parameters change drastically through the incorporation of carbon nanotubes.

Polyaniline/carbon nanotube composites in sensor applications

Polyaniline (PA) has outstanding electronic, electrical and chemical properties. The incorporation of carbon nanotubes (CNT) into PA matrix could result in PA/CNT nanocomposites that possess enhanced properties. This review outlines the preparation methods of PA/CNT nanocomposites where they could be prepared by in situ polymerization and solution mixing. In addition, the fabrication methods of electrodes based on PA/CNT nanocomposites to be used in sensors will be investigated. In this regard, such electrodes can be fabricated through in situ synthesis of PA/CNT on electrode surface, electro-polymerization of Ani on carbon nanotube-modified electrode or casting of the prepared PA/CNT on the electrode surface. Also, the use of PA/CNT nanocomposites as sensing materials in biosensors, gas sensors, metal ion sensors, environmental pollutants sensors and pH sensors will be highlighted. The use of such nanocomposites in various types of sensors could be attributed to their remarkable chemical properties, large surface area and outstanding electrical performance.

Electromagnetic Interference Shielding Effectiveness of Natural and Chlorobutyl Rubber Blend Nanocomposite

The science and technology of electrical equipment for communication experience a rapid growth rate. However, the unwanted interference of electromagnetic waves of different electronic devices brought serious anxiety about human health as well as the lifetime and performance of the systems. To combat these consequences, we need to lessen the electromagnetic wave emission by making our devices more noise-sensitive. Herein, we incorporated carbon nanotubes (CNTs) at different ratios into natural rubber (NR) and chlorobutyl rubber (CIIR) to achieve shielding efficiency, along with carbon nanofibers (CNFs), nanoclay (NC), and carbon black (CB) to manipulate EMI shielding performance. The blend of CIIR/NR in a 70/30 (w/w) ratio also mixed with CNT, CNF, CB and NC. The effect of different fillers and their concentration/combination was analyzed by UV spectroscopy, demonstrating an absorbance peak in CIIR in 320 nm. From FTIR spectroscopy, it was evident that CIIR/CNT (5 phr), NR (30 wt.%)/CIIR (70 wt.%)/CB (5 phr), and NR (30 wt.%)/CIIR (70 wt.%)/CNT (5 phr) new bonding signatures were detected. The dielectric spectroscopic analyses were reflected in dielectric loss, dielectric permittivity and AC conductivity, where NR (30 wt.%)/CIIR (70 wt.%)/CB (5 phr) blend nanocomposite with 5 dB showed significantly higher EMI shielding performance compared to CIIR/CNT (5 phr) and CIIR/CNF (5 phr) with 29 and 15 dB, respectively. The greater the concentration of nanofiller, the lower the electromagnetic interference (EMI) shielding, i.e., CIIR/CNT (10 phr) with 15 dB (≈−48% dB), but with more agglomeration. Surprisingly, even a combination of fillers did not lead to higher EMI performance, such that CIIR/CNT (5 phr)-CB (20 phr) showed an EMI shielding value of 59 dB.

A comparative study on the interfacial characteristics and tensile behaviors of natural rubber composites reinforced by carbon and boron nitride nanotubes

AbstractThe reinforcing effect of carbon nanotubes (CNTs) and boron nitride nanotubes (BNNTs) on the interfacial characteristics and tensile behaviors of natural rubber (NR) composites were comparatively investigated using molecular dynamics simulations. A pull‐out simulation was performed to study the interfacial characteristics between CNTs, BNNTs and NR matrices. The results showed that increases of about 56.63% and 90.14% in the interfacial frictional force and interfacial shear strength were obtained for the composites by the incorporation of BNNTs than those by the incorporation of CNTs. A uniaxial tensile process was fulfilled by using the constant true strain rate method to study the mechanical properties of the NR composites reinforced by CNTs and BNNTs. The results indicated that significant increases of 22.34% and 26.59% in the Young's modulus, 4.34% and 19.28% in the yield stress, and 11.07% and 8.01% in the tensile strength were respectively achieved by the incorporation of CNTs and BNNTs as reinforcements. To deeply reveal the deformation mechanisms of the NR composites, the mean square displacement and root‐mean‐square radius of gyration of the NR chains, the fractional free volume in the NR composites, and the interfacial interaction energy were calculated and discussed accordingly.

Probing the Carrier Dynamics of Polymer Composites with Single and Hybrid Carbon Nanotube Fillers for Improved Thermoelectric Performance

The incorporation of carbon nanotubes (CNTs) within polymer hosts offers a great platform for the development of advanced thermoelectric (TE) composite materials. Over the years, several CNT/polymer composite formulations have been investigated on an effort to maximize the TE performance. Meanwhile, several studies focused on the decay dynamics of the charged excitons within CNTs itself and therefrom derived structures, aiming to investigate the lifetimes and the corresponding recombination processes of free charge carriers. The latter physical phenomena play a crucial role in the performance of various types of energy converting and scavenging materials. Nevertheless, up to this date, there is no systematic study on the combination of TE parameters and the critical charge carrier dynamics within CNT containing TE polymer composites. Herein, a variety of composites with single and hybrid CNT fillers based on polycarbonate (PC) and polyether ether ketone (PEEK) polymer matrices were prepared by melt-mixing in small scale. At the same loading, the addition of single fillers in PC results in higher Seebeck coefficients and similar conductivities when compared to the use of hybrid filler systems. In contrast, with hybrid filler systems in PEEK composites, higher power factors could be reached than in single filler composites. Moreover, the PC-based composites are studied using ultrafast laser time-resolved transient absorption spectroscopy (TAS), for the investigation of the exciton lifetimes and the physical origins of free charge carrier transport within the TE films. The findings of this study reveal interesting links between the TE parameters and the obtained charge carrier dynamics.

Polyester-based polyurethane mixed-matrix membranes incorporating carbon nanotube-titanium oxide coupled nanohybrid for carbon dioxide capture enhancement: Molecular simulation and experimental study

In this study, polyester-based polyurethane mixed matrix membranes (MMMs) incorporating carbon nanotube (CNT)@TiO2 coupled nanohybrid is introduced for CO2 capture. Multi-wall CNTs were exploited with TiO2 nanoparticles to fabricate a novel highly-selective nanocomposite with reduced filler aggregation in the polymer matrix. Also, an enhanced dissolution of highly condensable CO2 molecules was observed due to acting titanium sites as Lewis acid sites and high affinity of CNT to the CO2 molecules. Three different molar ratios of CNT:TiO2 were hybridized in order to obtain an optimum composition. Polyurethane (PU) was synthesized using 1:3:2 M ratio of polyol:diisocyanate:chain extender. MMMs were fabricated employing the solution blending and casting method. The Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscope, and X-ray photoelectron spectroscopy were used to characterize the [email protected]2 nanohybrids. Field-emission scanning electron microscope confirmed the even distribution of the [email protected]2 nanohybrids in the PU matrix. Moreover, all prepared membranes crystallinity was examined conducting XRD, and differential scanning calorimetry. Also, phase separation between the soft and hard segments of fabricated PU membranes was examined using FTIR. Further study on various loadings of the optimum [email protected]2 in the membrane matrix (0.25, 0.5, 0.75, and 1 wt%) showed that the nanohybrid content increment up to 0.5c raises CO2 permeability, CO2/N2 ideal selectivity, and CO2/CH4 ideal selectivity by 39.64, 40.85, and 57.33%, respectively, at 12 bar and 25 °C. In addition, molecular simulation (MS) was applied for further investigation into structural and transport properties of the PU/[email protected]2 MMMs. The obtained results of MS correlate well with those of experiments.

State‐of‐the‐art review on the high‐performance poly (ether ether ketone) composites for mechanical, tribological and bioactive characteristics

AbstractPoly‐ether‐ether‐ketones (PEEK) exhibit a distinctive combination of thermo‐oxidative stability, chemical and solvent resistance, toughness, stiffness, and other mechanical properties, flame resistance at elevated temperatures. The promising applications in different fields evolved on several modifications, incorporating functional fillers, nanoparticles, fibers, etc. The incorporation of carbon fiber, carbon nanotubes, and graphene improves remarkably the mechanical, electrical and structural performance, precisely thermal stability, mechanical properties, thermal and electrical conductivity. The inorganic nanoparticles such as WS2, SiO2, or Al2O3 improve the matrix's tribological properties; particularly wear resistance and the coefficient of friction. Poly‐ether‐ether‐ketones is a biocompatible polymer that has gained a lot of attention as a replacement of metallic implants and other orthopedic, spinal, trauma, and dentistry applications. It has recently been used in cranioplasty to provide better protection. Bioactive surface modification of carbon–PEEK composites has only been documented in a few researches. PEEK is preferred because of its similar biocompatibility, elasticity to the bone, and radiolucency; however, due to its inert properties, it fails to integrate with the bone. Titanium (Ti) and Ti‐alloys are widely used in many intraosseous implants due to their biocompatibility and ability to osseointegrate. This review article provides a comprehensive overview of the research on PEEK‐based composites, mainly mechanical, tribological and bioactive performance. PEEK and PEEK‐based composites are also explored in terms of additive manufacturing. The impact of the preparation conditions, processing parameters, type of reinforcement, and the functional filler's concentration level on the structure and properties of the resultant materials are discussed. Finally, the current and potential applications and the future prospective recommendations are proposed in the last section.

Film casting of polycarbonate/multi-walled carbon nanotubes composites using ultrasound-assisted twin-screw extruder: experiment and simulation

Abstract A one-step ultrasonic film casting process to manufacture nanocomposite films was developed, in which polycarbonate (PC) was mixed with multi-walled carbon nanotubes (CNT) and cast into films in one process. Numerical and experimental investigations of necking phenomenon were carried out for film casting of PC/CNT composites. Experimental results revealed that the necking along film line decreased with imposition of ultrasound and increasing CNT content, indicating that incorporation of CNT and imposition of ultrasound restrained the elongational flow behavior of melt, resulting in film of a larger width. Isothermal and nonisothermal numerical simulations of the process were performed. In isothermal simulations, the polymer melt was assumed to be maintained at the die temperature. In nonisothermal simulations, the temperature change along the film line was determined from heat transfer calculations with the WLF temperature-dependent viscosity. The simulated and experimental results on normalized film width, defined as a ratio of cast film width to die width, as a function of the distance from the die at various extension ratios were compared. The comparison indicated that changes in film width and thickness along the stretching direction in the nonisothermal process were in better agreement with experimental results than that in the isothermal process. Both experimental and simulated results showed a decrease of film width with take-up speed. Due to the presence of edge effect, the film width in experiment was lower than the simulated one. With incorporation of CNT, a better agreement between experimental and simulated results was obtained, due to a reduced edge effect in the film.