Multi-walled Carbon Nanotubes Loading Research Articles

Highly Thermally Conductive Triple-Level Ordered CNT/PVA Nanofibrous Films.

The escalating thermal power density in electronic devices necessitates advanced thermal management technologies. Polymer-based materials, prized for their electrical insulation, flexibility, light weight, and strength, are extensively used in this field. However, the inherent low thermal conductivity of polymers requires enhancement for effective heat dissipation. This work proposes a novel paradigm, emphasizing ordered structures with functional units, to create triple-level, ordered, low-filler loading of multi-walled carbon nanotube (MWCNT)/poly(vinyl alcohol)(PVA) nanofibrous films. By addressing interfacial thermal resistance through -OH groups, the coupling between polymer and MWCNT is strengthened. The triple-level ordered structure comprises aligned PVA chains, aligned MWCNTs, and aligned MWCNT/PVA composite fibers. Focusing on the filler's impact on thermal conductivity and chain orientation, the thermal transport mechanisms have been elucidated level by level. Our MWCNT/PVA composite, with lower filler loadings (10 wt.%), achieves a remarkable TC exceeding 35.4 W/(m·K), surpassing other PVA composites with filler loading below 50 wt.%.

Wearable Fabric Sensor Using Functionalized MWCNT Nanocomposite Material

Despite the recent advancements in sensor detection of biomarkers in sweat, there is no sensor capable of long-term detection in constricted or load-bearing applications where other flexible plastic sensors might cause discomfort. In this work, a carbon nanotube-based fabric sensor capable of real-time detection of sodium in human sweat is presented. The sensor consists of an electrospun nylon-6 base functionalized with multi-walled carbon nanotubes for enhanced conductivity and p-tert-calix[4]arene for enhanced sodium selectivity. Monitoring sweat is a compelling choice to gain insight into a person’s hydration at a molecular level, as sweat is rich in physiological and metabolic information that can be obtained non-invasively. Body surface sweat is approximately 99% water but also contains over 40 other compounds, most notably the presence of extracellular ions: sodium and chloride. Sodium has been shown to have a notable correlation to body fluid balance and is lost in ample quantities during exercise, making it a promising candidate for the detection of dehydration (i.e., hypernatremia) and overhydration (i.e., hyponatremia). Other compounds commonly found in surface sweat include intracellular ions, metabolites, hormones, small proteins, and peptides. This rich composition and its correspondence to blood chemistry can be the key to accessing the body’s biomolecular (health) state through non-invasive monitoring and diagnostics.When monitoring biomarkers in sweat, the sampling step has the greatest impact on accuracy. Traditional methods for monitoring sweat sodium concentration involve collecting a sweat sample and performing chemical analysis in two separate steps. Typical sweat collection procedures include whole body washdown, sweat collection patches, arm bags, and Macroducts® which require some combination of tedious procedures, trained professionals, and large equipment for analysis. These methods are often limited by insufficient sample volumes, non-negligible sample evaporation, possible analyte degradation between sampling and analysis all of which strongly impacts the reliability and sensitivity of the measurement.To circumvent the problems caused by separating sampling and analysis, sweat sampling can also be completed using wearable sensors. Through in-situ sampling and analysis, wearable sweat sensors can perform the necessary real-time measurements with freshly generated sweat rather than a mixture of new and old sweat. Functional absorbent materials (e.g., paper, nonwoven, cellulosic, or hydrogels) are typically introduced between the skin and the sensing component; although as shown in this work, they can also be introduced as sensing components during sampling. The advantages of functional absorbent sensing materials are their low cost, multiple functions, real-time and continuous sensing, and most importantly the enhanced breathability of sweat glands. As such, these wearable sensors avoid the issue of altering the sweat composition underneath because they remove the old sweat accumulation as new sweat wicks into the material and washes away old sweat. This also allows physiological monitoring for longer periods of time than traditional epidermal microfluidic devices. Additionally, functional absorbent materials can also be integrated into fabrics with inherent moisture wicking properties to bring sweat to a sensing area.This work presents the characterization and on-body testing of a previously developed functional absorbent material sensor made of a multi-walled carbon nanotube (MWCNT) functionalized nylon-6 nanocomposite. The wearable-fabric sensor works by measuring resistance of the nanocomposite material as sodium binds to the sensor fabric. The functionalization of the nanocomposite material was verified by FTIR; while XRD spectra show that the electrospun nylon-6 is made of -form crystals and the resulting nanocomposite is intercalated/exfoliated with an increase in crystalline size. The optimized MWCNT/nylon-6 nanocomposite sensor has a MWCNT loading close to the percolation threshold at approximately 1-2 wt%. Experimental results demonstrated that the sensor is selective to sodium in sweat at a sensitivity of 10 mM sodium. When worn on the body (attached to human skin), the sensor is capable of real-time monitoring of sodium concentration in sweat in the physiologically relevant range of 10-110 mM with up to 85% accuracy. Additionally, the obtained signal can be sent out via Bluetooth so that changes in hydration status can be detected in real-time.Overall, this carbon nanotube-based fabric sensor can be integrated into “smarter” clothing to read an array of biomarkers in sweat. This could lead to better understanding of health and disease processes (e.g., analysis of common diabetic neurological complications, diagnosis of cystic fibrosis (CF), sweat monitoring for advanced prosthetic limb applications and bedridden patients, and athlete performance tracking) resulting in better treatments and health outcomes for all patients.

Multi-wall carbon nanotubes tailored eutectic composites for solar energy harvesting

Carbonaceous thermal energy storage involving PCMs has gained an increasing research interest owing to their higher thermal conductivity and energy storage density. The current work analyses the thermophysical properties of a nano-enhanced eutectic phase change material (NeUPCM) laden with different concentrations (ranges from 0 wt% - 0.7 wt%) of multi-wall carbon nanotube (MWCNT). Paraffin wax-palmitic acid (PW-PA) binary eutectic was produced initially by facile melt blending, and then MWCNTs were doped via standard two-step nanocomposite synthesis protocol. Nanocomposites showed a slower decomposition rate, and the thermal resistance index improved. MWCNT enhance the thermal conductivity of the eutectic base (140 %), which reaches a maximum value of 0.619 W/(m·K) for 0.5 wt% loadings, and the maximum increment of 13.2 % of latent heat was noted for 0.7 wt% loading of MWCNT (which is having a melting temperature of 53 °C). The sample doped with 0.5 wt% MWCNT(C3) showed the highest thermal effusivity. The NeUPCMs also displayed improved photothermal performance and solar absorptivity. Corrosion analysis against copper revealed that the composite is suitable for long-term usage. The NeUPCMs maintained good reliability even after 500 melt-freeze cycles. In short, the proposed NeUPCMs hold significant potential to be employed for thermal energy storage purposes.

Lightweight, porous, stretchable nanocomposite foams with sandwich-like and bimodal cell structure by supercritical fluids-assisted processing for flexible strain sensor

Developing strain sensors with wide detection range and high sensitivity at a low conductive nanofillers content still faces challenges. Herein, thermoplastic polyurethane (TPU)/multi-walled carbon nanotubes (MWCNTs) nanocomposite foams with a multilayer alternating and bimodal cell structure is prepared by stacking hot pressing and supercritical carbon dioxide batch foaming process. Consequently, the synergistic effect of sandwich-like and bimodal cell structure endows the foam sensor of FTPU-C3-L10 T80P10 (TPU/3wt.%MWCNTs nanocomposite foams with ten layers alternating structure foamed at 80℃ and 10MPa) 0.34 vol.% MWCNTs loading, broad response range of 0~150%, high sensitivity with a gauge factor (GF) of 101, fast response speed of 180 ms, as well as cyclic reproducibility and durability of 1000 cycles. Furthermore, the fabricated foam sensor can effectively monitor basic human motion from tiny to large. This work provides a facile strategy for designing and producing strain sensors applied in various fields, including human motion detection, artificial intelligence devices, and medical diagnosis.

Rheological percolation, gel‐like behavior and electrical conductivity of multi‐walled carbon nanotubes filled ethylene‐vinyl acetate copolymer/acrylonitrile‐butadiene rubber nanocomposites

AbstractReasonable studies on the composite systems containing conductive nanoparticles are very important to manufacture the materials with physico‐mechanical tailor‐made properties. In this work, rheological percolation, gel‐like behavior and electrical properties of multi‐walled carbon nanotubes (MWCNTs) filled ethylene‐co‐vinyl acetate/acrylonitrile‐butadiene copolymer blends containing 0–7 wt% MWCNTs were studied. The Winter‐Chambon criterion validity was evaluated for physical gelation of the system. The rheological and electrical percolation threshold, gel point (Pg), relaxation exponent (n), gel strength (Sg), and the fractal dimension (df) at the gel point were calculated. The formation of physical gel and rheological percolation threshold were both found to occur at 1 wt% MWCNTs concentration. Based on the df value determined, it was revealed that the system behaved similar to the one in which the excluded volume interactions were nearly screened. It was also found that the storage modulus (G′) near the Pg followed a power‐law scaling relationship in the form where is the distance from Pg. The electrical conductivity of the nanocomposites increased with the increase in MWCNTs loading after the nanofillers content surpassed a certain value. A schematic model was proposed to demonstrate the variation of electrical conduction with the increase in MWCNTs concentration. The excluded volume and hard‐core models were also employed to estimate the average aspect ratio of the nanofillers embedded in the system.Highlights Morphology and gel‐like behavior of EVA/NBR/MWCNTs system were studied Winter‐Chambon criterion was found to be valid for the gelation of the system Rheological percolation and gel point were occurred at the same MWCNTs loading It was found excluded volume interactions were nearly screened at gel point A schematic model for microstructure development was suggested for the system

One-pot synthesis of a CdS–MoS2 / CNTs nano-composite for photocatalytic hydrogen production under visible light

The need to meet growing energy demands of global society in a sustainable fashion requires the development of techniques and processes to reduce dependence on fossil fuels and transit to renewable energy sources. Environmentally benign technologies for alternative fuel production in the form of hydrogen can be developed via heterogenous photocatalysis, a process based on utilization of solar energy. To this end, a cadmium sulfide (CdS) based photocatalyst was developed, doped with MoS2 in a one-pot solvothermal synthesis technique, and coupled with multi-walled carbon nanotubes (MWCNTs) as a carbonaceous support. The material exhibiting the highest rate of hydrogen evolution, CM5C3, involved a MWCNTs loading of 3% and MoS2 loading of 5%. Compared to pure CdS synthesized with the same adapted procedure, the 3% CNT loading improved the rate of hydrogen production by nearly 7-fold, and the optimal 5% MoS2 loading further improved the performance by 60%. CM5C3, achieved an apparent quantum efficiency of 7.34%, a 26-fold increase compared to pure CdS. FESEM and HRTEM imaging confirmed the nanorod-like growth of CdS–MoS2 on the CNT surface, with elemental mapping confirming homogenous dispersion of MoS2 and CNTs. In addition, lattice fringe spacings indicated the presence of cubic and hexagonal CdS growing predominantly along the (111) and (002) planes respectively, in addition to MoS2 distributed throughout the crystal lattice. XRD analysis confirmed the presence of hexagonal and cubic CdS, however, MoS2 phases were not registered perhaps due to the low concentration present in the bulk of the material. XPS survey scans showed the presence of C, Cd, Mo, and S only, with trace oxygen impurities. Peak deconvolution indicated the presence of characteristic peaks for CdS and MoS2, in addition to evidence of the presence of Cd–C bonds, indicating strong CdS heterojunctions to the CNT surface.

Exploration of synergic effect assessment on the electrochemical behaviour of graphene and multiwall carbon nanotube (MWCNT) modified BiFeO3-MoS2 heterogeneous composites

Nanocomposite systems of BiFeO3-MoS2, BiFeO3-MoS2-MWCNT, and BiFeO3-MoS2-graphene have been synthesized through the sol-gel method. The synthesized composite powders were taken for various characterization tools like XRD, Raman, FT-IR, UV–Vis-NIR, FE-SEM, and electrochemical studies. XRD, Raman, FT-IR, and FE-SEM studies have confirmed the formation of binary and ternary composites. The loading of graphene and MWCNT on the BiFeO3-MoS2 systemsis reasonably tuned to the band gaps. Electrochemical measurements suggest that the synergic effect was found to have decreased in ternary composites (BiFeO3-MoS2-graphene and BiFeO3-MoS2-MWCNT) when compared to the binary composites (BiFeO3-MoS2). The electrochemical results of the synthesized composite have been discussed in detail.

Low temperature charge transport study of MWCNT/PEDOT:PSS composites: insulating to metallic regime

Multiwall carbon nanotube (MWCNT)/poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) composites have been examined for their temperature and magnetic field dependent conductivity behavior. The conductivity ratio, σ r (σ 300 K/ σ 2 K), is significantly impacted by the sulfuric acid post-treatment of the composites and a slight alteration in MWCNTs loading. By adjusting the loading of MWCNTs in the composites, the charge transport is tuned from insulating to metallic regime. For the low loading of MWCNTs (0.04 wt%), charge transport of the composite lies in the insulating regime and follows a variable range hopping model. At moderate loading of MWCNTs, the transport of the composites lies in the critical regime and the temperature dependent conductivity follows a power law model. As the MWCNTs loading increases to 4 wt%, transport of the composites shifts to the metallic regime with σ r ∼ 2.8. The temperature dependent conductivity has been explained by using electron-electron interactions and weak localization effects and the conductivity follows ∼T 1/2 and ∼T 3/4 dependence in different temperature regimes. Wave function shrinkage and forward interference effects have been used to evaluate the magnetoconductance (MC) of the samples located in the insulating regime. For the composites lying in the metallic regime, a dominant contribution from weak localization explains the behaviour of the MC. However, for those in the critical regime a combined effect of weak localization and electron-electron interactions has been observed.

On twin substantially improved thermal properties and stability of pyrrolidinium-based ionanofluids with long multi-walled carbon nanotubes

The quest for advanced heat transfer fluids with superior thermal properties has led to the exploration of ionanofluids (INFs). Such systems are composed of ionic liquids (ILs) and thermoactive dispersed nanoparticles, and offer promising opportunities for the enhanced heat transfer. In this work, we selected long multi-walled carbon nanotubes (MWCNTs) as well as 1-propyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C3C1pyr][NTf2]) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C4C1pyr][NTf2]) as base liquids. The chosen ILs have the same thermal conductivity and similar viscosity which results in the ‘twin’ thermal conductivity of related INFs in the whole range of MWCNTs loading as well as similar rheological performance. We find the remarkable synergistic effects of incorporating 5.0 wt% of long MWCNTs into [C3C1pyr][NTf2]-based INF, resulting in a sky-rocketing 560% increase in thermal conductivity of INF compared to the base IL. The [C4C1pyr][NTf2]-based INFs exhibited excellent thermal and sedimental long-term stability (4 years), characterized by change in thermal conductivity and in density lower than declared uncertainties. We proved that remarkably enhanced thermal conductivity was mainly influenced by the high aspect ratio of MWCNTs enabling formation of long-range, 3D nanotube networks additionally stabilized by nanolayers of IL on the MWCNTs surface.

Buckling analysis of sandwich plates reinforced with various loading of multi-walled carbon nanotubes

The current investigation aims to examine the buckling behavior of sandwich structures reinforced with faces containing varying weight percentages (wt.%) of multi-walled carbon nanotubes (MWCNT), through the combined employment of experimental and numerical analysis techniques. In particular, the numerical analysis is executed through the implementation of the generalized differential quadrature method (GDQM). The study first determines the mechanical properties of the pure and reinforced samples via experimental tests. The buckling equations of the sandwich plate are then derived using the Frostig approach and a high-order shear deformation theory (SDT) for the flexible core. The continuity conditions between the faces and the core are considered to obtain the structural equations of the system, and Lagrange coefficients are introduced to enhance the accuracy of the governing equations. Subsequently, the study investigates the impact of various parameters, such as core thickness, aspect ratio, different boundary conditions (BC), and the addition of MWCNT nanoparticles on the critical buckling load of the system, utilizing the mechanical properties obtained for the composite faces. The present investigation reveals that the incorporation of MWCNT into the composite matrix brings about notable enhancements in the mechanical characteristics of sandwich structures. Specifically, the elastic modulus and ultimate strength of the faces are found to increase following the addition of MWCNT. Additionally, the critical buckling load of the sandwich plates is observed to rise with an increase in aspect ratio and length-to-thickness ratio, while a decrease in axial load yields similar results. The clamped boundary condition has higher critical buckling loads than the simply supported boundary condition. The addition of MWCNT nanoparticles decreases the dimensionless critical buckling force as the b/a ratio increases. Finally, the reported results of the current investigation present noteworthy findings about the advancement and improvement of sandwich composite structures to meet various application requirements.

Piezoresistive behavior of MWCNT/PA12 honeycomb composites processed via selective laser sintering

This study examines the piezoresistive and mechanical behaviors of multiwalled carbon nanotube (MWCNT)/polyamide (PA12) lattice composites processed via selective laser sintering (SLS). Firstly, neat PA12 powder was ballmilled with either 0.3, 0.5, or 1.0 wt% MWCNT loading to obtain nanoengineered powder feedstocks. The feedstocks were used to realize electrically conductive MWCNT/PA12 bulk and honeycomb lattice structures via SLS. The piezoresistive and mechanical characteristics of bulk samples were assessed under tensile, compressive, and flexure loadings while those of honeycombs were investigated under in-plane and out-of-plane compression. The morphological and thermal characterizations were carried out to gain insight into the processing-structure-property relations. The microstructural observations, including in situ μ-CT imaging, revealed that the porosity of the sintered parts significantly increased (≈150%) with increasing MWCNT loading, resulting in reduced elastic stiffness and strength of the sintered composites, despite their slightly higher crystallinity (+6% for 0.5 wt% MWCNT loading). The bulk nanocomposites exhibited excellent piezoresistive characteristics, showing a maximum gauge factor of 31 (in compression), which is significantly higher than the sensitivity factors of extant piezoresistive self-sensing composites. The honeycomb structures showed a maximum specific energy absorption of 3 and 24 J g−1 at 40% relative density under in-plane and out-of-plane compression loading, respectively. It was also demonstrated, that the MWCNT/PA12 honeycombs possess excellent strain sensing characteristics due to their pronounced piezoresistivity, reporting gauge factors up to 25 and 17 for in-plane and out-of-plane loading, respectively.

Multi-Walled Carbon-Nanotube-Reinforced PMMA Nanocomposites: An Experimental Study of Their Friction and Wear Properties.

This manuscript presents an experimental investigation of the friction and wear properties of poly (methyl methacrylate) (PMMA) nanocomposites reinforced with functionalized multi-walled carbon nanotubes (MWCNTs). The aim of this study is to evaluate the potential of MWCNTs as a reinforcement material for enhancing the tribological performance of PMMA. Three types of multi-walled carbon nanotubes, i.e., pristine, hydroxyl functionalized, and carboxyl functionalized, were utilized in this study. The nanocomposite samples were prepared by dispersing varying concentrations of MWCNTs (0.1 wt.%, 0.5 wt.%, and 1 wt.%) within the PMMA matrix via a 3D mixing approach, followed by injection molding/compression molding. The resulting nanocomposite films were characterized using scanning electron microscopy (SEM) to observe the dispersion of MWCNTs within the PMMA matrix. The friction and wear tests were conducted using a pin-on-disk tribometer under dry sliding conditions. The effects of functionalization and MWCNT content on the tribological behaviors of the nanocomposites were analyzed. The nanocomposites exhibited lower friction coefficients and reduced wear rates compared to pure PMMA. The lowest friction coefficient and wear rate were achieved at an optimum MWCNT loading of 0.5 wt.%. It was further revealed that the amount of MWCNT reinforcement, average load, and track diameter significantly affect the coefficient of friction (COF) and rate of wear. The COF and wear rate are best at a filler loading of 0.5 wt.%, a 20 Kg load, and 90 mm. The improved tribological performance of the MWCNT-reinforced PMMA nanocomposites can be attributed to the effective transfer of load between the MWCNTs and the PMMA matrix, as well as the reinforcement effect of the MWCNTs. The MWCNTs acted as reinforcing agents, enhancing the mechanical properties and wear resistance of the nanocomposites.

Multifunctional characteristics of 3D printed polymer nanocomposites under monotonic and cyclic compression

This study presents the multifunctional characteristics of multi-walled carbon nanotube (MWCNT)/polypropylene random copolymer (PPR) composites enabled via fused filament fabrication (FFF) under monotonic and quasi-static cyclic compression. Utilizing in-house MWCNT-engineered PPR filament feedstocks, both bulk and cellular composites were realized. The morphological features of nanocomposites were examined via scanning electron microscopy, which reveals that MWCNTs are uniformly dispersed. The uniformly dispersed MWCNTs forms an electrically conductive network within the PPR matrix, and the resulting nanocomposite shows good electrical conductivity (⁓10−1S/cm), improved mechanical performance (modulus increases by 125% and compressive strength increases by 25% for 8 wt% MWCNT loading) and pronounced piezoresistive response (gauge factor of 27.9–8.5 for bulk samples) under compression. The influence of strain rate on the piezoresistive response of bulk samples (4 wt% of MWCNT) under compression was also measured. Under repeated cyclic compression (2% constant strain amplitude), the nanocomposite exhibited stable piezoresistive performance up to 100 cycles. The piezoresistive response under repeated cyclic loading with increasing strain amplitude of was also assessed. The gauge factor of BCC and FCC cellular composites (4 wt% of MWCNT) with a relative density of 30% was observed to be 46.4 and 30.2 respectively, under compression. The higher sensitivity of the BCC plate-lattice could be attributed to its higher degree of stretching-dominated deformation behavior than the FCC plate-lattice, which exhibits bending-dominated behavior. The 3D printed cellular PPR/MWCNT composites structures were found to show excellent piezoresistive self-sensing characteristics and open new avenues for in situ structural health monitoring in various applications.

Free-standing polymer/multiwalled carbon nanotubes composite thin films for high thermal conductivity and prominent EMI shielding

Lightweight composite materials with efficient thermal conductivity (TC) and high electromagnetic interference (EMI) shielding effectiveness (SE) are of paramount importance for a wide range of applications such as electronics, aerospace, and stealth technology. In this work, lightweight, flexible, and free-standing poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/multiwalled carbon nanotube (MWCNT) composite thin films are fabricated by a single-step, solution casting method. Fabricated PVDF-HFP/MWCNT composite thin films are characterized by many physicochemical techniques such as Raman spectra, Fourier transform infrared spectra, X-ray diffractometer, and high-resolution transmission electron microscope. The resulting composite thin film exhibits a TC of 1.1 Wm−1K−1 at room temperature. Further analysis shows that the TC of the composite film is increased up to 1.8 Wm−1K−1 at 100 °C. As fabricated flexible and free-standing composite thin film (thickness ∼ 150 µm) exhibit an excellent EMI SE of ∼ 36 dB in the X-band region (8.2–12.4 GHz) at just 15 wt. % loading of MWCNT. The outstanding EMI shielding and high TC of PVDF-HFP/MWCNT composite films are attributed to the homogenous distribution and well-connected network of MWCNT within the polymer matrix, forming a conductive network throughout the composite film.

Probing the Electro-Chemical and Thermal Properties of Polyaniline/MWCNT Nanocomposites

The tremendous interest for robust, clean energy storage devices to comprehend the growing needs of modern gadgets has led to exploration of materials having unprecedented electrochemical and interfacial properties. Here, the present study deals with the synergistic effects of multi walled carbon nanotubes and polyaniline nanocomposites on the electro-chemical and thermal properties for wide-range of applications. The microstructural, structural, and optical characterizations have been evaluated through scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV-Vis spectrophotometry. The thermal stability of the product was also studied through thermal gravimetric analysis (TGA) and the room temperature electrical conductivity was also measured. An exceptional enhancement in thermal stability and conductivity has been observed apparently due to interfacial properties of polyaniline (PANI) and multiwalled carbon nanotubes (MWCNTs). Further, in present study we are going to report a comparative analysis of thermal and electrical properties of PANI/MWCNT nanocomposites with different loadings of MWCNTs. The room temperature conductivity as calculated for 1%, 2%, 4% and 8% MWCNT loading is around 2.019, 3.075, 4.48, 8.73 S/cm respectively. The mechanism for thermal and electrical enhancements in PANI-coated MWCNT nanocomposites is also expounded.

A comprehensive investigation of the low-velocity impact response of enhanced GFRP composites with single and hybrid loading of various types of nanoparticles

This study investigates the effects of incorporating various types of nanoparticles, both singularly and in hybrid form, on the low-velocity impact (LVI) response of glass fiber reinforced polymer (GFRP) composites. GFRP composites were fabricated using the hand lay-up method and different weight percentages (wt. %) of multi-walled carbon nanotubes (MWCNT), clay, TiO2, and CuO nanoparticles were added into the matrix of composites. To test the LVI response, 14 types of specimens were fabricated with single and hybrid nanoparticle loadings, and LVI tests were conducted using 5 and 10-cm span dimensions at two levels of subjected energy. The experimental results reveal that specimens with a single loading of MWCNT or nano-clay have a lower maximum contact force compared to pure specimens with fully rebounding behavior. This indicates that neither 5 nor 10 cm spans result in severe damages during the impact tests. Furthermore, incorporating more MWCNTs results in stiffer behavior and more brittleness. The study also explores the synergetic effect of adding hybrid nanoparticles in the fabricated composites and discusses the calculated results for absorbed energy. Finally, scanning electron microscopy (SEM) images are analyzed to evaluate the enhancement mechanisms resulting from the addition of nanoparticles to GFRP composite specimens.

Electrospun multiwall nanotubes-loaded polyethylene glycol/polyacrylonitrile composite form-stable nanofibers for thermal energy storage

In this paper, multiwall carbon nanotubes (MWCNTs) were introduced into PAN/PEG composite phase change nanofibers to solve the problems of low thermal conductivity and easy leakage of phase change materials. The effects of MWCNTs loadings on the microscopic morphology, structural, thermal, and mechanical properties of the electrospun PAN/PEG composite nanofibrous membranes were characterized using scanning electronic microscope (SEM), Fourier transformation infrared spectroscope (FT-IR), Raman spectroscopy, differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA) and mechanical testing machine. The results indicated that the electrospun PAN/PEG composite nanofibers with 10 wt% MWCNTs loading had reasonable melting enthalpy (78.3 J/g), improved phase change material leakage, excellent thermal reliability and stability. Thermal energy storage and release experiments presented that 10 wt% MWCNTs-loaded nanofibrous membranes could play a good role in thermal energy modulation. Therefore, the PAN/PEG/MWCNT composite nanofibrous membranes are potential materials for thermal energy storage and temperature-regulated textile applications.

Morphological Electrical and Hardness Characterization of Carbon Nanotube-Reinforced Thermoplastic Polyurethane (TPU) Nanocomposite Plates.

The impacts on the morphological, electrical and hardness properties of thermoplastic polyurethane (TPU) plates using multi-walled carbon nanotubes (MWCNTs) as reinforcing fillers have been investigated, using MWCNT loadings between 1 and 7 wt%. Plates of the TPU/MWCNT nanocomposites were fabricated by compression molding from extruded pellets. An X-ray diffraction analysis showed that the incorporation of MWCNTs into the TPU polymer matrix increases the ordered range of the soft and hard segments. SEM images revealed that the fabrication route used here helped to obtain TPU/MWCNT nanocomposites with a uniform dispersion of the nanotubes inside the TPU matrix and promoted the creation of a conductive network that favors the electronic conduction of the composite. The potential of the impedance spectroscopy technique has been used to determine that the TPU/MWCNT plates exhibited two conduction mechanisms, percolation and tunneling conduction of electrons, and their conductivity values increase as the MWCNT loading increases. Finally, although the fabrication route induced a hardness reduction with respect to the pure TPU, the addition of MWCNT increased the Shore A hardness behavior of the TPU plates.

Cytotoxicity Analysis for the Hydroxyl Functionalized MWCNT Reinforced PMMA Nanocomposites in Oral Squamous Carcinoma (KB) Cells.

In this particular research study, a unique three-dimensional mixing technique was used to incorporate multi-walled carbon nanotubes (MWCNTs) into polymethyl methacrylate (PMMA), and the KB cell line was used in the analysis of cytotoxicity, apoptosis detection, and cell viability using the MTT assay protocol. At low concentrations (0.001 to 0.1 g/mL), these results showed that the CNT did not seem to cause cell death or apoptosis directly. It increased lymphocyte-mediated cytotoxicity against KB cell lines. This was demonstrated by the fact that the CNT increased the time it took for KB cell lines to die. In the end, the unique three-dimensional mixing method solves problems such as clumping and uneven mixing that have been written about in the relevant literature. Phagocytic uptake of MWCNT-reinforced PMMA nanocomposite by KB cells leads to oxidative stress and apoptosis induction in a dose-dependent manner. The cytotoxicity of the generated composite and the ROS (reactive oxygen species) it produces may be controlled by adjusting the MWCNT loading. The conclusion that can be drawn from the studies to date is that it could be possible to treat some types of cancer using PMMA that has MWCNTs incorporated into it.

Poly(Butylene Succinate) Hybrid Multi-Walled Carbon Nanotube/Iron Oxide Nanocomposites: Electromagnetic Shielding and Thermal Properties.

To address the ever-increasing electromagnetic interference (EMI) pollution, a hybrid filler approach for novel composites was chosen, with a focus on EMI absorbance. Carbon nanofiller loading was limited to 0.6 vol.% in order to create a sustainable and affordable solution. Multiwall carbon nanotubes (MWCNT) and iron oxide (Fe3O4) nanoparticles were mixed in nine ratios from 0.1 to 0.6 vol.% and 8.0 to 12.0 vol.%, respectively. With the addition of surfactant, excellent particle dispersion was achieved (examined with SEM micrographs) in a bio-based and biodegradable poly(butylene succinate) (PBS) matrix. Hybrid design synergy was assessed for EMI shielding using dielectric spectroscopy in the microwave region and transmittance in the terahertz range. The shielding effectiveness (20-52 dB) was dominated by very high absorption at 30 GHz, while in the 0.1 to 1.0 THz range, transmittance was reduced by up to 6 orders of magnitude. Frequency-independent AC electrical conductivity (from 10-2 to 107 Hz) was reached upon adding 0.6 vol.% MWCNT and 10 vol.% Fe3O4, with a value of around 3.1 × 10-2 S/m. Electrical and thermal conductivity were mainly affected by the content of MWCNT filler. The thermal conductivity scaled with the filler content and reached the highest value of 0.309 W/(mK) at 25 °C with the loading of 0.6 vol.% MWCNT and 12 vol.% Fe3O4. The surface resistivity showed an incremental decrease with an increase in MWCNT loading and was almost unaffected by an increase in iron oxide loading. Thermal conductivity was almost independent of temperature in the measured range of 25 to 45 °C. The nanocomposites serve as biodegradable alternatives to commodity plastic-based materials and are promising in the field of electromagnetic applications, especially for EMI shielding.