Addition Of Carbon Nanotubes Research Articles

Effect of the addition of aliphatic diamine-functionalized carbon nanotubes on the interfacial adhesion of glass fiber/epoxy composites

To improve the interfacial adhesion of glass fiber (GF)/epoxy composites, the GF surface was treated by dispersing aliphatic diamine-functionalized multi-walled carbon nanotubes (MWCNTs). Carboxyl MWCNTs were first modified by aliphatic diamine with different alkyl chain lengths and then deposited on the surface of GF. The effect of aliphatic diamine chain lengths on the MWCNTs’ dispersion and interfacial properties of resultant composites was investigated in detail. The results showed that uniform dispersion of MWCNTs and strong fiber/matrix interfacial adhesion could be achieved, based on the grafting of 1,8-octanediamine onto MWCNTs. Compared with the control sample, the interlaminar shear, flexural, and tensile strengths of the treated composites increased by 41%, 29%, and 30%, respectively; the interlaminar fracture toughness and storage modulus in the glass region were significantly enhanced; and the glass transition temperature increased by more than 8°C. This work demonstrates that the carbon nanotubes functionalized by appropriate chain lengths of amine modifier can improve the fiber/matrix interfacial interactions and thus enhance the strength, toughness, and stiffness of fiber-reinforced composites.

Preparation and Gas Separation Performance of Polysulfone Mixed Matrix Membrane

As an economical, environmentally friendly, and highly efficient separation technology, membrane separation is a popular research topic in the field of separation. Organic polymer materials have attracted considerable attention in membrane separation because of their controllable preparation processes, simple modification method, and high toughness. Taking polysulfone (PSF) as the substrate of gas separation membrane, we prepared the mixed matrix membrane jointly by using the solution casting method and by adding graphene oxide (GO) and carbon nanotubes (CNTs). On this basis, the permeability of the membrane for CO2 and N2 and the permeability coefficient of the mixed gas were studied. With the addition of CNTs and GO, the permeability of gas was significantly improved. At 0.2 MPa, permeability of CO2 increased from 553 Barrer to 975 Barrer, and permeability of N2 increased from 536 Barrer to 745 Barrer. The max ideal separation coefficient of CO2 and N2 is 1.94 at 0.1 MPa. Increasing of the content of carbon nanotubes can significantly improve the permeability coefficient of CO2, while the change of inlet side pressure has a great impact on the permeability coefficient of N2. At 0.1 MPa, when the ratio of CNTs to GO was 5 : 1, the ideal permeability coefficient of CO2/N2 was 1.94, whereas the ideal permeability coefficient of PSF membrane was 1.46. The above results of PSF/GO/CNT mixed matrix membrane lay a theoretical foundation for industrial application.

High-performance solar-driven interfacial evaporation through molecular design of antibacterial, biomass-derived hydrogels

Hydrogel has been regarded as one of the most promising candidates for next-generation solar evaporation technology to produce freshwater from non-potable water. However, synthesizing hydrogel absorbers that can precisely regulate water state and significantly reduce the water vaporization enthalpy remains a grand challenge. Herein, we report the rational design of a novel hydrogel hybrid solar evaporator constructed by poly(vinyl alcohol) and sodium lignosulfonate (SLS), with addition of carbon nanotube as a light absorption material. The abundant sulfonate and hydroxyl groups of SLS enhance the interplay between hydrogel and water molecule through electrostatic interaction and hydrogen bond. As such, the presence of SLS not only remarkably promotes the hydrophilicity and water transport of hydrogel, but also precisely tunes the state of water molecule and the content of intermediate water for reducing the water vaporization enthalpy. The combined advantageous features endow the as-prepared hydrogel with an evaporation rate up to 2.09 kg m−2 h−1 under 1 Sun illumination, along with good anti-acid/basic abilities, antibacterial property, high salt-tolerance, and self-cleaning capability in purifying different types of wastewater. Finally, an outdoor solar seawater desalination device is designed to generate drinking water from seawater. The daily drinking water production amount per square meter is ca. 13 kg, which satifies the five adults' daily water consumption (12.5 kg). The present study highlights that rationally constructing the molecular architecture of hydrogel and tuning the interplay between water and hydrogel are effective strategies to fabricate advanced hydrogel solar evaporators for addressing the global freshwater shortage.

Effect of different processing techniques on hardness, electrical and thermal conductivity of Copper/Carbon nanotube composites for industrial applications

The performance of Copper (Cu) can be enhanced by the addition of carbon nanotubes (CNT) as reinforcement in order to utilize it for prolonged industrial applications, where the mechanical and thermal properties are often appropriate for them. The aim of the current work is to develop the Cu/CNT composite products via novel molecular level mixing (MLM) technique followed by cold isostatic pressing (CIP) and microwave sintering (MW). Besides, the results are compared with the sample processed through uniaxial compaction (UA) followed by either conventional sintering (CS) or microwave sintering (MW) technique. The grain size of CIP-MW processed composites is found to be enhanced with size of CNT diameter, CNT content and sintering time in comparison to that of Copper. The maximum properties of Cu/CNT composites are obtained irrespective of the size of CNT diameter as follows: Relative density - 93.8%, Hardness - 83.2 ± 2.1 VHN, Electrical conductivity - 50.4 ± 0.2 MS/m and thermal conductivity - 372.8 W/mK. The thermal conductivity of CIP-MW processed Cu/CNT composites is found to have superior characteristics in comparison to that of UA-CS and UA-MW processing techniques and the reported results are at par with the highly expensive and high-end technique like spark plasma sintering.

Mechanical Properties of Polylactide Admixed with Carbon Nanotubes or Graphene Nanopowder.

The aim of this work was to verify the material properties of polylactic acid (PLA) with an addition of carbon nanotubes (CNTs) or graphene nanopowder (GNP). The pure polylactide and admixed polylactide samples were subjected to chemical–physical tests to determine their stiffness and strength parameters. The tensile and impact tests were performed on samples without UV (ultraviolet) treatment and after UV treatment, in a physiological saline solution. The investigations were composed of two stages. The first one was related to the examination of the properties of pure polylactide, denoted as the following: 3001D, 4032D, and 4043D. The second stage was based on an analysis of the properties of PLA 4032D with an admixture of GNP or CNTs, at 0.1 wt.% and 0.5 wt.%. By comparing the strength and the stiffness of pure samples with samples with the considered admixtures, an essential increase was not observed. However, it is stated that the presence of GNP and CNTs in the samples positively influenced the resistance of the materials to the ageing process.

Evaluation the Effect of Adding Silanized Silicon Dioxide Nano Filler and Carbon Nanotube Composite on Some Properties of Heat Cured Acrylic Denture Base Material

The mechanical properties of polymethyl methacrylate (PMMA) are still far from ideal to fulfill the perfect mechanical requirements for dental applications. The purpose of this study was to evaluate the effect of addition of silanized silicon dioxide Nano filler (SiO2) and carbon nanotube on some properties of heat cured acrylic resin denture base material.Materials and methods: One hundred sixty (160) prepared specimens were divided into 4 groups according to the tests, each group consisted of 40 specimens and these were subdivided into 4 groups (unreinforced heat cured acrylic resin as control group),reinforced acrylic resin with (1%wt carbon nanotube and 3%wt silanized silicon dioxide) group and reinforced acrylic with(1.5%wt carbon nanotube and 5%wt silanized silicon dioxide)and reinforced acrylic with (1.5%wt carbon nanotube and 7%wt silanized silicon dioxide) .The tensile strength, transverse strength, indentation hardness(shore D), water sorption and solubility were investigated . The results were statistically analyzed using ANOVA test with LSD multiple comparisons.Results: The result of this study shows a highly significant increase in tensile strength, surface hardness, transverse strength and significant decrease water sorption and water solubility with studied groups (the addition of carbon nanotube and silanized silicon dioxide) to PMMA than control group, also the best results were obtained with acrylic resin reinforced with(1.5%wt carbon nanotube and 5%wt silanized silicon dioxide).Conclusion: The addition of a mixture of carbon nanotube (1.5%wt) and silanized nano silicon dioxide (5%wt) to PMMA acrylic resins improves its mechanical and physical properties.

Polymer Blends and Polymer Nanocomposites for Photovoltaic (PV) Cells and an Investigation of the Material Deposition Techniques in PV Cell Fabrication

Polymer photovoltaics (PV) offer the advantage of low-cost, mass-produced, flexible PV films, but they generally suffer from a low-power conversion efficiency (PCE) compared to silicon. This paper studies ITO/PEDOT:PSS/bulk heterojunction/Al PV cells, where two different bulk heterojunction blends are researched: P3HT/PC61BM and PCDTBT/PC70BM. The addition of multiwall carbon nanotubes (CNT) is explored as a conductive network to accelerate the electron transport and extraction to the outer aluminium current collector while reducing the chance of charge recombinations. Several layer deposition techniques are investigated: spin coating and casting, as well as techniques that would induce transverse orientation of polymer grains, including inkjet printing, electrophoresis and the application of a transverse AC field during annealing. Transverse orientation techniques produced architectures that would facilitate charge transport without recombinations, but it is recommended to avoid such techniques for the deposition of conductive PEDOT:PSS and CNT layers as they create a high surface roughness that leads to short circuiting. The best performing PV cell is the ITO/PEDOT:PSS/PCDTBT/PC70BM/CNT/Al structure with a PCE of 11%.

Attaining Toughness and Reduced Electrical Percolation Thresholds in Bio-Based PA410 by Combined Addition of Bio-Based Thermoplastic Elastomers and CNTs.

Multi-walled carbon nanotubes (CNTs) were added to provide electrical conductivity to bio-based polymer blends with improved toughness (based on commercially available Pebax thermoplastic elastomers and bio-based polyamide 4,10). A preliminary study including three different Pebax grades was carried out to select the grade and the composition that would best improve the impact properties of PA410. Thus, tough multiphasic PA/Pebax/CNT nanocomposites (NCs) with enhanced electrical conductivity were obtained. The CNTs were added either: (1) in the form of pristine nanotubes or (2) in the form of a PA6-based masterbatch. Hence, PA410/Pebax/CNT ternary NCs and PA410/PA6/Pebax/CNT quaternary NCs were obtained, respectively, up to a CNT content of 1 wt%. The ternary and quaternary NCs both showed similar mechanical and electrical properties. The electrical percolation threshold decreased with respect to previously studied corresponding NCs without Pebax, i.e., PA410/CNT and PA410/PA6/CNT, due to the partial volume exclusion effect of Pebax over the CNTs that were dispersed mainly in the PA matrix; materials with percolation concentrations as low as 0.38 wt% were obtained. With respect to mechanical properties, contrary to the NCs without Pebax, all the PA/Pebax/CNT NCs showed a ductile behavior and impact strength values that were from three to five-fold higher than that of the pure PA410.

Experimental studies on the effect of Carbon nanotube additives with Calophyllum Inophyllum biodiesel in CI engine

The rapid depletion of Non-renewable fuel sources coupled with environmental degradation, has led us further into the exploration of alternate energy resources. Biodiesels originating from non-edible feedstocks have garnered much attention in a span of few years. The current study focuses on the addition of Carbon Nanotubes in Tamanu oil biodiesel in a Diesel engine. In this study, parameters such as brake thermal efficiency, unburned hydrocarbon, carbon monoxide, and NOx emissions have been studied. The performance of these biodiesel-diesel blends were charted and results are compared with diesel. It is noted that the inclusion of nano-additives in dosages of 30 and 60 ppm enhances brake thermal efficiency, the drawback being increased specific fuel consumption. The emissions of HC, NOx and emissions show a favorable trend with addition of CNT but CO2 emissions were observed to be on the higher side. Also graphs were plotted revealing the relevant combustion characteristics of the test fuels. They are further discussed in detail and a comprehensive conclusion was made.

Electrical Properties of Transformer Oil with the Addition of Extremely Low Concentrations of Carbon Nanotubes

Electrical properties of transformer oil with additives of carbon nano-tubes are studied at the extremely low concentrations of the nano-tubes. Electrical strength of the mixtures is more than an order of magnitude lower than that of pure oil. Strengthening of the large gap is registered after several breakdowns in contrast to the small gap. The formation of a carbon bridge between flat electrodes is registered optically. This bridge is destroyed by an electrical discharge in the chain of bubbles generated on the bridge. Experiments with helium bubbles floating up in the mixture of carbon nano-tubes with transformer oil are performed at the deficiency of initiating electrons. Additives of carbon nano-tubes stimulate the partial discharges in the bubbles. Also, at lower voltages, the development of intense micro-flows in the liquid dielectric is observed that can be the result of the injection of free electrons from the nano-tubes.

Studies on Mechanical and Flexural Strength of Carbon Nano Tube Reinforced with Hemp/Vinyl Ester/Carbon Fiber Laminated Hybrid Composite

Abstract: In Recent days, the natural fibres from renewable natural resources offer the potential to act as a reinforcing material for polymer composites alternative to the use of glass, carbon and other man-made fibres. Among various fibres, Hemp is most widely used natural fibre due to its advantages like easy availability, low density, low production cost and satisfactory mechanical properties. Composite materials play a vital role in the field of materials to meet the stringent demands of light weight, high strength, corrosion resistance and near-net shapes. Composite is a structural material that consists of two or more combined constituents that are combined at a macroscopic level and are not soluble in each other. Composites are having two phases that are reinforcing phase like fiber, particle, or flakes & matrix phase like polymers, metals, and ceramics. In this project an attempt is made to prepare different combination of composite materials using hemp/carbon fiber and Carbon nano tube reinforcement and vinyl ester as the matrix material respectively. Composites were prepared according to ASTM standards and following test are carried out Tensile, Flexural and ILSS test. The effect of addition of Carbon nano tubes in hemp/vinyl ester/carbon fibers has been studied & it has been observed that there is a significant effect of fibre loading and performance of hemp/carbon fiber reinforced vinyl ester based hybrid composites with improved results Keywords: Hemp fiber, Vinyl ester, Carbon fiber, Tensile, Flexural and ILSS Test

Fibers of Thermoplastic Copolyamides with Carbon Nanotubes for Electromagnetic Shielding Applications.

Polymer composites containing carbon nanofillers are extensively developed for electromagnetic shielding applications, where lightweight and flexible materials are required. One example of the microwave absorbers can be thermoplastic fibers fabricated from copolyamide hot melt adhesives and 7 wt% of multi-walled carbon nanotubes, as presented in this paper. A broadband dielectric spectroscopy confirmed that the addition of carbon nanotubes significantly increased microwave electrical properties of the thin (diameter about 100 μm) thermoplastic fibers. Moreover, the dielectric properties are improved for the thicker fibers, and they are almost stable at the frequency range 26–40 GHz and not dependent on the temperature. The variances in the dielectric properties of the fibers are associated with the degree of orientation of carbon nanotubes and the presence of bundles, which were examined using a high-resolution scanning microscope. Analyzing the mechanical properties of the nanocomposite fibers, as an effect of the carbon nanotubes addition, an improvement in the stiffness of the fibers was observed, together with a decrease in the fibers’ elongation and tensile strength.

4D-Printed Resins and Nanocomposites Thermally Stimulated by Conventional Heating and IR Radiation

The shape memory (SM) capabilities of nanocomposites based on two photocurable acrylated/methacrylated resins, doped with carbon nanotubes (CNTs), and manufactured by digital light processing 3D printing were investigated. The mechanical properties and glass transition temperature (Tg) can be tailored in a broad range by varying the weight ratio of the two resins (Tg ranging from 15 to 190 °C; Young’s modulus from 1.5 to 2500 MPa). Shape fixity (SF) and recovery (SR) ratios are strongly influenced by the temperature being significantly higher at temperatures close to the Tg. The results confirm that the SF strongly depends on the stiffness of chain segments between cross-linking points, whereas the SR mainly depends on the cross-link density of the network. CNT addition barely affects the SF and SR in the conventional oven, whereas the recovery speed using IR heating is significantly increased for the doped nanocomposites due to their higher IR absorbance.

Cam Fiber Sandviç Kompozitlerin Düşük Hızlı Darbe Mukavemetinin Nano Parçacık Takviyeli Yapıştırıcı Kullanılarak Artırılması

The use of sandwich composite structures in the aerospace industry is increasing. Improving the impact and other mechanical properties of sandwich composite panels (SCP) is important for aviation safety. In the manufacture of SCPs, bonding with the lower and upper surfaces of the honeycomb structure is provided by bonding connections. By improving the mechanical properties of the adhesives used in SCP, the mechanical rigidity of the whole structure will be improved. In this study, sandwich composite panels were produced using glass fiber reinforced composite, three different adhesives (pure polyurethane, 0.1% and 0.2% multi-walled carbon nanotube reinforced polyurethane) and an aluminum honeycomb with a cell diameter of 8.86 mm. Low-velocity impact tests were applied to the manufactured sandwich composites at the initial energy level of 50 J. After impact tests, load-time, load-deflection and energy-time graphs were obtained, and the effect of multi-walled carbon nanotube (MWCNT) contribution was evaluated. Also, the effect of the MWCNT addition on impact properties was determined by making a damage analysis. It was observed that the carbon nanotube addition to the polyurethane adhesive increased the maximum contact force by 3%, improving the low-speed impact properties of SCPs.

Study on Ultraviolet Aging Mechanism of Carbon Nanotubes/SBS Composite-Modified Asphalt in Two-Dimensional Infrared Correlation Spectroscopy.

In order to explore the influence mechanism of carbon nanotubes on the ultraviolet (UV) aging properties of the SBS-modified asphalt binder, the changes of functional groups in the one-dimensional infrared spectrum and two-dimensional infrared correlation spectrum are studied in this paper. The results show that the UV aging process of the SBS-modified asphalt binder is the process of alkane chain cleavage and reorganization, the formation of oxygen-containing functional groups and decomposition of SBS. The incorporation of carbon nanotubes can reduce the mutual conversion of methyl and methylene functional groups, inhibit the decomposition of butadiene and the destruction of C = C double bonds in SBS. The degradation of SBS during the process of UV aging leads to the change of many functional groups and acceleration of the aging of the SBS-modified asphalt binder. The addition of carbon nanotubes can effectively alleviate the degradation of SBS and the formation of oxygen-containing functional groups at the early stage of UV aging, and reduce the influence of these two changes on other functional groups; thus, improving the anti-aging performance of the SBS-modified asphalt binder.

Understanding the effect of processing temperature and carbon nanotube addition on the viscoelastic response of polyurethane foams

AbstractWe experimentally demonstrate a strategy to design the microstructure and hence viscoelastic behavior of polyurethane (PU) foams. PU foams are fabricated at two temperatures (room and −5°C) and reinforced with varying concentrations of oxidized carbon nanotubes (CNTs). Hierarchical pores, thicker cell walls, higher density, and low porosity are recorded in PU foams processed at −5°C. The addition of CNTs improves the cell wall stiffness and thermal stability of PU foams. Master curves constructed from dynamic mechanical analysis show that processing at −5°C and addition of 1.6 wt.% oxidized CNTs enhance the storage modulus of PU foams over a wide temperature and frequency range. Prony series analysis reveals that PU foams fabricated at −5°C have significantly lower relaxation time. Moreover, the elastic modulus of PU foams processed using optimized conditions shows stronger rate dependency in comparison to other types of PU foams fabricated in this work.

Optimization of the Rheological Properties and Tribological Performance of SAE 5w-30 Base Oil with Added MWCNTs

The augmentation of lubricant oil properties is key to protecting engines, bearings, and machine parts from damage due to friction and wear and minimizing energy lost in countering friction. The tribological and rheological properties of the lubricants are of utmost importance to prevent wear under unembellished conditions. The marginal addition of particulate and filamentous nanofillers enhances these properties, making the lubricant oil stable under severe operating conditions. This research explores the improvement in SAE 5w-30 base oil performance after the addition of multiwalled carbon nanotubes (MWCNTs) in six marginal compositions, namely, Base, 0.02, 0.04, 0.06, 0.08, and 0.10 weight percentage. The effect of the addition of MWCNTs on flash and pour points, thermal conductivity, kinematic viscosity, friction coefficients, and wear are investigated and reported. X-ray diffraction and transmission electron microscopy are used to characterize the MWCNTs. The purity, crystallinity, size, shape, and orientation of the MWCNTs are confirmed by XRD and TEM characterization. Pour points and flash points increase by adding MWCNTs but inconsistency is observed after the 0.06 wt.% composition. The thermal conductivity and kinematic viscosity increase significantly and consistently. The friction coefficient and wear scar diameter reduce to 0.06 wt.% MWCNTs and then the trend is reversed due to agglomeration and inhomogeneity. A composition of 0.06 wt.% is identified as the optimum considering all the investigated properties. This composition ensures the stability of the tribo-film and hydrodynamic lubrication.

Enhancing the electrochemical performances of Li2S-based cathode through conductive interface design and addition of mixed conductive materials

The significantly-high theoretical energy density and eco-sustainability of lithium sulfur batteries (LSBs) arouses a rapid surge of interest in recent years. However, some key issues of cathode, for instance, the polysulfides confinement, low ion/electrons transfer and etc., hinder the practical utilization of LSBs. Herein, such issues could be carefully handled by using the conductive polypyrrole as polysulfides wrapper. The polypyrrole with pyrrole rings can efficiently confine polysulfides inside cathode for redox. Meanwhile, the conductive polypyrrole with delocalized π-electron cloud can facilitate electrons transfer. Besides, the addition of carbon nanotube (CNT) and oxidized graphene (GO) can enhance the conductivity of cathode material. As a result, the Li2S/CNT/GO/PPy cathode delivers a cycling capacity of 525 mAh g−1 with a low-capacity decay rate of 0.065 % cycle−1 after 400 cycles. Therefore, the lithium-sulfur battery with Li2S-based and PPy-wrapped cathode could reasonably be counted as a potential alternative of long-cycling Li-ion cells.

Effects of the addition of CNTs and Al alloying on the microstructure and properties of Cu-(Al)/CNTs composites

In this study, carbon nanotubes (CNTs) reinforced CuAl based composite materials were prepared by powder metallurgy. Al powders were mechanically mixed with Cu powders. Al diffused under high temperature sintering to strengthen the matrix via alloying with Cu and forming a transition interface between CNTs and Cu to improve the interfacial bonding. The microstructure and tensile properties of the Cu-Al/CNTs composites were characterized. The effects of the addition of CNTs, Al alloying and hot rolling processing on the microstructure and properties of the composites were analyzed. The results indicate that after spark plasma sintering and hot rolling, the tensile strength and yield strength of the Cu-1Al/0.5 vol% CNTs composite reached 34.0% and 100% higher than that of the Cu/0.5 vol% CNTs composite without Al addition, and an elongation of 41% was still maintained.

Study of the influence of nanoparticles on the behavior of composite materials

The objective of this work is to study the influence of additives of multi-walled carbon nanotubes (MWCNT) and silica nano-powder (SiO2) on the mechanical behavior of epoxy resin. Different volume fractions of MWCNT and SiO2were added. Mechanical characterization by tensile, three-point bending and Charpy tests were carried out. The experimental results show an increase in the mechanical performance of the mixtures (MWCNT ​+ ​epoxy), (SiO2 ​+ ​epoxy) up to 2% of additive. Beyond this value, a degradation of performance was observed. The addition of MWCNT gives better results when compared to the addition of SiO2. KIC-KCV correlations were made using empirical formulas to estimate the critical stress intensity factor KIC from the impact energy of the Charpy test.Unfortunately, this estimation does not provided a promising results, but other optimization methods were used to fit these empirical models to the behavior of our nanocomposites for which a good estimate was obtained after fitting these empirical models for SiO2.