Monthly Archives: April 2016

Properties of MWCNT

Properties of MWCNT

Carbon Nanotubes are an example of true nanotechnology. They are less than 100 nanometers in diameter and can be as thin as 1 or 2 nm. They are molecules that can be manipulated chemically and physically in very useful ways. They open an incredible range of applications in materials science, electronics, chemical processing, energy management, and many other fields. There are two structural models of multi-walled nanotubes. The carbon nanotube contains another nanotube inside it (the inner nanotube has a smaller diameter than the outer nanotube). The single graphene sheet is rolled around itself multiple times, resembling a rolled up scroll of paper. Multi-walled carbon nanotubes have similar properties to single-walled nanotubes, yet the outer walls on multi-walled nanotubes can protect the inner carbon nanotubes from chemical interactions with outside materials. Multi-walled nanotubes also have a higher tensile strength than single-walled nanotubes.

properties of mwcnt

properties of mwcnt

Properties of MWCNT: Hardness

The hardness of cast samples has increased by the addition of MWCNTs, for the base alloy to  for the 2.5% weight fraction reinforced nanocomposites. It can be observed from the that the hardness values have slightly increased for 0.5 and 1% weight fractions, while they have increased for 1.5, 2, and 2.5 wt% by a considerable value. It can be observed that the hardness values have slightly increased for 0.5 and 1% weight fractions, while they have increased for 1.5, 2, and 2.5 wt% by a considerable value. The reason for the hardness increasing is that MWCNTs improve in strengthening and hardening the matrix by increasing the matrix alloy dislocation density during cooling to room temperature and due to the difference of the coefficients of thermal expansion between the CNTs and the matrix. . According to observation by Landry et al. during sintering and cooling the distribution of dislocations within the matrix of the composites would not be uniform and there will be higher density near the reinforcing particles. The reason for the decrease in the density is due to the addition of light weight and high volume CNTs compared to the matrix material, which increases the porosity of the nanocomposite samples.

Properties of MWCNT: Tensile Strength

It can be observed that the tensile strength has increased with the increase of MWCNT content reaching optimal value at 1.5 wt% MWCNTs. The tensile strength increases from MPa for the base alloy to an average value of MPa for 1.5 wt% MWCNTs weight fraction reinforced composite. At the optimal amount of multiwall carbon nanotubes (1.5 wt%), the ultimate tensile strength and yield strength of the composite were enhanced by 50% and 60%, respectively, compared to the alloy matrix. The increase in the mechanical properties can partly be attributed to coupled effects of increase in grain boundary area due to grain refinement, the strong thermal stress at the interface induced by the large difference of coefficient of thermal expansion between the matrix and MWCNTs reinforcement, and the effective transfer of tensile load to the uniform distribution of MWCNTs. However, increasing the amount of MWCNTs above 1.5 wt% was found to deteriorate the tensile strength of the composite to a value of MPa for 2.5 wt% MWCNTs reinforced composite. The lower value of strength for the 2.5 wt% reinforced composite may be attributed to difficulties of hydrogen entrapment during the reinforcement addition. Adding of MWCNTs above the optimal value will make the composite become more brittle.

Properties of MWCNT: Electrical Conductivity

CNTs can be highly conducting, and hence can be said to be metallic. Their conductivity has been shown to be a function of their chirality, the degree of twist as well as their diameter. CNTs can be either metallic or semi-conducting in their electrical behavior. Conductivity in MWNTs is quite complex. Some types of “armchair”-structured CNTs appear to conduct better than other metallic CNTs. Furthermore, interwall reactions within multi walled nanotubes have been found to redistribute the current over individual tubes non-uniformly. However, there is no change in current across different parts of metallic single-walled nanotubes. The behavior of the ropes of semi-conducting single walled nanotubes is different, in that the transport current changes abruptly at various positions on the CNTs. A nanotube with a natural junction (where a straight metallic section is joined to a chiral semiconducting section) behaves as a rectifying diode – that is, a half-transistor in a single molecule. It has also recently been reported that single walled nanotubes can route electrical signals at speeds up to 10 GHz when used as interconnects on semi-conducting devices.

Properties of MWCNT: Strength and Elasticity

The carbon atoms of a single sheet of graphite form a planar honeycomb lattice, in which each atom is connected via a strong chemical bond to three neighboring atoms. Because of these strong bonds, the basal plane elastic modulus of graphite is one of the largest of any known material. For this reason, properties of mwcnt are expected to be the ultimate high-strength fibers. Single walled nanotubes are stiffer than steel, and are very resistant to damage from physical forces. Pressing on the tip of a nanotube will cause it to bend, but without damage to the tip. When the force is removed, the nanotube returns to its original state. This property makes CNTs very useful as probe tips for very high-resolution scanning probe microscopy. Quantifying these effects has been rather difficult, and an exact numerical value has not been agreed upon.

Properties of MWCNT: Thermal Conductivity and Expansion

CNTs have been shown to exhibit superconductivity below 20°K (aaprox. -253°C). these exotic strands, already heralded for their unparalleled strength and unique ability to adopt the electrical properties of either semiconductors or perfect metals, may someday also find applications as miniature heat conduits in a host of devices and materials. The strong in-plane graphitic carbon – carbon bonds make them exceptionally strong and stiff against axial strains. The almost zero in-plane thermal expansion but large inter-plane expansion of single walled nanotubes implies strong in-plane coupling and high flexibility against non-axial strains. Many applications  properties of mwcnt such as in nanoscale molecular electronics, sensing and actuating devices, or as reinforcing additive fibers in functional composite materials, have been proposed.

Properties of MWCNT: Field Emission

Field emission results from the tunneling of electrons from a metal tip into vacuum, under application of a strong electric field. The small diameter and high aspect ratio of CNTs is very favorable for field emission. Even for moderate voltages, a strong electric field develops at the free end of supported properties of mwcnt because of their sharpness. He also immediately realized that these field emitters must be superior to conventional electron sources and might find their way into all kind of applications, most importantly flat-panel displays. It is remarkable that after only five years Samsung actually realized a very bright color display, which will be shortly commercialized using this technology.

  • Water filtration membranes
  • Electronics & Semiconductors
  • Chemical & Polymers
  • Batteries & Capacitors
  • Energy
  • Medical
  • Composites
  • Aerospace & Defense
  • Water filtration membranes

Membrane filtration is recurrently employed technique for water purification. Commendable membranes must present reduced thermal conductivity, amplified hydrophobicity and superior penetrability. Polymers or additives accompanied by the formation strategy of membrane have been accounted to engender such physiognomies. In order to purify through hydrophilic polymer membrane, surface charge and porosity exhibit crucial parts to eradicate various pollutants of kinds like microorganisms, organic contaminants and inorganic particles from the treatment of superfluous. Biological adsorbates like bacteria and virus have sizes of more than microporous adsorbents. Depending on the size dissimilarity, greatest amount of biological pollutants have un-approachability to the surface area of pores, restricting the removal. Recently, nanotechnology has industrialized various nanomaterials like multi-walled carbon nanofiller (MWCNT)/polymer-based nanocomposite, etc.

The poor dispensability of pristine carbon nanotubes in water impedes their implications in thin-film nanocomposite membranes for crucial utilities such as water purification. In this work, high-flux positively charged nanocomposite nanofiltration membranes were exploited by uniformly embedding poly(dopamine) modified multiwall carbon nanotubes (PDA-MWCNTs) in polyamide thin-film composite membranes. With poly(dopamine) modification, fine dispersion of MWCNTs in polyethyleneimine (PEI) aqueous solutions was achieved, which was interracially polymerized with trimesoyl chloride (TMC) n-hexane solutions to prepare nanocomposite membranes. The compatibility and interactions between modified properties of mwcnt and polyamide matrix were enhanced, attributed to the poly(dopamine) coatings on MWCNT surfaces, leading to significantly improved water permeability. At optimized conditions, pure water permeability of the PEI/PDA-MWCNTs/TMC nanofiltration membrane (M-4) was 15.32 L m–2 h–1 bar–1, which was ∼1.6 times increased compared with that of pristine PEI/TMC membranes. Salt rejection of M-4 to different multivalent cations decreased in the sequence ZnCl2 (93.0%) > MgCl2 (91.5%) > CuCl2 (90.5%) ≈ CaCl2, which is well-suited for water

Properties of Mwcnt: Electronics & Semiconductors

Electrically conductive adhesives (ECA) are an alternative to tin/lead solders for attaching Surface Mount Devices (SMD) in electronic assemblies. ECAs are mixtures of a polymer binder (for adhesion) and conductive filler (for electrical conductivity). They bring more conductivity, higher strength, less weight and longer durability than metal alloys. ECAs can offer numerous advantages such as fewer processing steps, lower processing temperature and fine pitch capability. Multi walled carbon nanotubes (MWCNT) were used as conductive fillers in this research because of their novel electronic and mechanical properties. The high aspect ratio of the nanotubes makes it possible to percolate at low loadings to obtain good electrical and mechanical properties. Replacing the metal filler with CNTs in the adhesive made the ECA light weight, corrosion resistant, reduced processing temperature, lead free, electrically conductive and high mechanical strength. The properties of mwcnt at different loadings were mixed with epoxy and epoxy: heloxy to form a composite mixture. Different loadings, additives and mixing methods were used to obtain good electrical and mechanical properties and pot life.

properties of mwcnt (CNTs) are minuscule allotropes of carbon with sizes to the scale of nanometers. The physical, electrical, and thermal properties of carbon nanotubes make them a special material for a number of applications. CNTs have very high tensile strength, excellent electrical conductivity, and the ability to bear high working temperatures. Despite challenges such as the high cost of production and integration issues, the CNT application market has made great breakthroughs. CNT enabled nanotechnology has made a huge impact on a wide range of applications such as electronics, medicine, aerospace, defense, automotives, energy and construction. With producers stepping up their production capacities, the prices of properties of mwcnt are set to decrease inducing a spiraling effect on application areas thereby pushing up demand.

microscale flexible energy storage device made of graphene and carbon nanotubes, which can store enough energy to rival the gold standard, lithium batteries. Batteries and supercapacitors both store energy, but there’s a catch. Batteries have a higher energy density which means they can store energy for longer periods, but they have low power density. That means they can’t discharge quickly.

Properties of Mwcnt :Batteries & Capacitors

Supercapacitors have the opposite problem: their low energy density means they can’t store as much energy, but their high power density enables them to deliver energy rapidly when needed. The trick to solving the energy density problem for supercapacitors is to find a material with a relatively high proportion of surface area available for energy storage. If we decrease the cost and increase the capacitive value and energy density, supercapacitor would be better option to compete with batteries in many applications areas.

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properties of mwcnt

properties of mwcnt

 

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Applications and Benefits of Multi-Walled Carbon

Applications and Benefits of Multi-Walled Carbon

These are Nanoparticles that are unique for their size, shape, and remarkable physical properties. They can be thought of as a sheet of graphite (a hexagonal lattice of carbon) rolled into a cylinder. These intriguing structures have sparked much excitement in recent years and a large amount of research has been dedicated to their understanding. Currently, the physical properties are still being discovered and disputed. Nanotubes have a very broad range of electronic, thermal, and structural properties that change depending on the different kinds of nanotube (defined by its diameter, length, and chirality, or twist). To make things more interesting, besides having a single cylindrical wall (SWCNTs), Nanotubes can have multiple walls (MWCNTs)–cylinders inside the other cylinders.

Applications and Benefits of Multi-Walled Carbon

Applications and Benefits of Multi-Walled Carbon

 

  • Extraordinary electrical conductivity, heat conductivity, and mechanical properties.
  • They are probably the best electron field-emitter known, largely due to their high length-to-diameter ratios
  • As pure carbon polymers, they can be manipulated using the well-known and the tremendously rich chemistry of that element.

Applications and Benefits of Multi-Walled Carbon: Strength

Carbon nanotubes have a higher tensile strength than steel. Their strength comes from the sp² bonds between the individual carbon atoms. This bond is even stronger than the sp³ bond found in diamond. Under high pressure, individual nanotubes can bond together, trading some sp² bonds for sp³ bonds. This gives the possibility of producing long nanotube wires. Carbon nanotubes are not only strong, they are also elastic. The tip of a nanotube and cause it to bend without damaging to the nanotube, and the nanotube will return to its original shape when the force is removed. A nanotube’s elasticity does have a limit, and under very strong forces, it is possible to permanently deform to shape of a nanotube. A nanotube’s strength can be weakened by defects in the structure of the nanotube. Defects occur from atomic vacancies or a rearrangement of the carbon bonds. Defects in the structure can cause a small segment of the nanotube to become weaker, which in turn causes the tensile strength of the entire nanotube to weaken. The tensile strength of a nanotube depends on the strength of the weakest segment in the tube similar to the way the strength of a chain depends on the weakest link in the chain.

Applications and Benefits of Multi-Walled Carbon: Electrical properties

The structure of a Multi Walled Carbon Nanotube determines conductive the nanotube.  The structure of atoms in a multi walled carbon nanotube minimizes the collisions between conduction. Electrons and atoms, a carbon nanotube is highly conductive. The strong bonds between carbon atoms also allow carbon nanotubes to withstand higher electric currents than copper. Electron transport occurs only along the axis of the tube. Multi walled nanotubes can route electrical signals at speeds up to 10 GHz when used as interconnects on semi-conducting devices. Nanotubes also have a constant resistively.

Applications and Benefits of Multi-Walled Carbon: Thermal Properties

The strength of the atomic bonds in Multi Walled carbon nanotubes allows them to withstand high temperatures. Because of this, multi walled carbon nanotubes have been shown to be very good thermal conductors. Compared to copper wires, which are commonly used as thermal conductors, the multi walled carbon nanotubes can transmit over 15 times the amount of watts per meter per Kelvin. The thermal conductivity of carbon nanotubes is dependent on the temperature of the tubes and the outside environment.

Applications and Benefits of Multi-Walled Carbon: Potential Uses

 There are many potential applications for multi walled Carbon nanotubes from waterproof and tear resistant cloth fabrics, concrete and steel like applications (a space elevator has even been proposed) based on the property of strength, electrical circuits based on the property of electrical conductivity, sensors based on the property of thermal conductivity, vacuum proof food packaging, and even as a vessel for delivering drugs. For the purpose of this paper we are going to focus on the applications related to nano-eletronics Carbon nanotubes (CNTs) including single-walled CNTs (SWCNTs) and multiwalled CNTs (MWCNTs) have attracted great attentions as a supporting material because of their excellent properties such as high surface area and chemical stability.

 

Key application areas

  • Batteries
  • Solar Cells
  • Transistors
  • Nano-Electronics
  • Flat Panel Display
  • Energy Storage.

Applications and Benefits of Multi-Walled Carbon: Batteries

Most portable electronic devices use rechargeable lithium-ion batteries. These batteries release charge when lithium ions move between two electrodes – one of which is graphite and the other is metal oxide. Demonstrated that by replacing the graphite with MWCNTs they can double storage capacity.

Electrodes made of carbon nanotubes can be ten times thinner and lighter than amorphous carbon electrodes and their conductivity is more than one thousand times greater. In some cases, such as electric vehicles, the reduction in weight can make a significant reduction in battery power requirements. Multi Walled Carbon nanotubes have been used in supercapacitors producing a power density of 30kw/kg (compared to 4kw/kg for commercially available devices). Such supercapacitors could drastically reduce the time it takes to recharge devices such as laptops and cell phones.

Applications and Benefits of Multi-Walled Carbon: Solar Cells

Solar cells consisting of 100- micrometer-high towers built of MWCNTs grown on iron-coated silicon wafers. There are 40,000 of these towers in each square centimeter of the surface; Each tower is an array of millions of vertically aligned MWCNTs. These cells absorb more light as it reflects off the sides of the towers. Unlike typical solar cells that have peak efficiency when the sun is at 90º, these cells have two peaks at 45° and operate with relatively high efficiency during most of the day. This makes them particularly appropriate for applications in space because it eliminates the requirement of having a mechanical means of orienting the cells to face the sun.

Applications and Benefits of Multi-Walled Carbon: Transistors

Transistors form the basis for modern integrated circuits functioning as digital switches. Alternative configurations of carbon-nanotubes result in defects being present that allow Multi walled nanotubes to act as transistors. Nanotube based switches the size of an individual electron had been envisioned but had originally required cryogenic like temperatures.

Applications and Benefits of Multi-Walled Carbon: Nano-Electronics

One of the most significant potential applications of Multi-walled nanotubes is believed to be in the domain of nano-electronics. This is as a result of MWNT’s being highly-conductive. Multi-walled nanotube ropes are the most conductive carbon fibers known. Alternative configurations of a carbon nanotube can result in the resultant material being semi-conductive like silicon. Conductivity in nanotubes is based on the degree of chirality – i.e. the degree of twist and size of the diameter of the actual nanotube – which results in a nanotube that is actually extremely conductive  or non-conductive (making it suitable as the basis for semi-conductors).

Applications and Benefits of Multi-Walled Carbon: Flat Panel Display

Prototype matrix-addressable diode flat panel displays have been fabricated using Multi Walled carbon nanotubes as the electron emission source. nanotube-epoxy stripes on the cathode glass plate and phosphor-coated Indium-Tin-Oxide (ITO) stripes on the anode plate. Pixels are formed at the intersection of cathode and anode stripes, as illustrated cathode-anode gap distance of 30μm, 230V is required to obtain the emission current density necessary to drive the diode display (∼ 76 μmA/mm2). The device is operated using the half-voltage off-pixel scheme. Pulses of ±150V are switched among anode and cathode stripes, respectively to produce an image. field emission display has been fabricated by Samsung, with MWCNT stripes on the cathode and phosphor-coated ITO stripes on the anode running orthogonally to the cathode stripes. MWCNTs synthesized by the arc-discharge method were dispersed in isopropyl alcohol and then mixed with an organic mixture of nitro cellulose.

Applications and Benefits of Multi-Walled Carbon: Energy Storage.

Multi Walled Carbon Nanotubes are being considered for energy production and storage. Graphite, carbonaceous materials and carbon fiber electrodes have been used for decades in fuel cells, battery and several other electrochemical applications. Nanotubes are special because they have small dimensions, a smooth surface topology, and perfect surface specificity, since only the basal graphite planes are exposed in their structure. The rate of electron transfer at carbon electrodes ultimately determines the efficiency of fuel cells and this depends on various factors, such as the structure and morphology of the carbon material used in the electrodes. The properties of catalytically grown carbon nanofibers have been found to be desirable for high power electrochemical capacitors.

 

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Applications and Benefits of Multi-Walled Carbon

Applications and Benefits of Multi-Walled Carbon

 

From us, you can easily purchase nano products at great prices. Place online order and we will dispatch your order through DHL, FedEx, UPS. You can also request for a quote by mailing us at sales@nanoshel.com Contact: +1 302 268 6163 (US and Europe), Contact: +91-9779550077 (India). We invite you to contact us for further information about our company and our capabilities. At Nanoshel, we could be glad to be of service to you. We look forward to your suggestions and feedback.


Carbon Nanomaterials in Agriculture

Carbon Nanomaterials in Agriculture

That tomato seeds exposed to carbon nanotubes (CNTs) germinated faster and grew into larger, heavier seedlings than other seeds. That growth-enhancing effect could be a boon for biomass production for plant-based biofuels and other agricultural products, they suggest. Considerable scientific research is underway to use nanoparticles wisps 1/50,000th the width of a human hair in agriculture. The goals of “nano-agriculture” include improving the productivity of plants for food, fuel, and other uses.

Carbon Nanomaterials in Agriculture

Carbon Nanomaterials in Agriculture

 

Carbon Nanomaterials in Agriculture: Nanotechnology permits broad advances in agriculture.

The impact of multi-walled carbon nanotubes (MWCNTs) on the accumulation/depuration behaviors of contaminants in crop, mustard (Brassica juncea), and  the permeability and transportability of MWCNTs in intact mature mustard plants. Using an in vivo sampling technique, the kinetic accumulation/depuration processes of several contaminants in mustard plans exposed to MWCNTs were traced, and an enhancement of contaminant accumulation in living plants was observed. Meanwhile, we observed that the MWCNTs permeated into the roots of intact living plants (three months old) and were then transported to the upper organs under the force of transpiration steam. This study demonstrated that MWCNTs can act as contaminant carriers and be transported to the edible parts of crops.

Carbon nanotubes (CNTs), with their combination of a microtubular structure and particular physical properties, are promising materials for biotechnology applications. CNTs also act as transporters to permeate into tumor cells, bacteria, plant cells, and animal tissues, which opened a new route for drug and gene delivery. In addition, there is extensive interest in applying CNTs to plants for agricultural use, and exciting achievements such as seed germination enhancement, root growth, and an increase in biomass have been reported. However, the fact is that nanotechnology is still in a relative early stage of development, which inevitably arouses consideration about the environmental, health, and safety impacts of the use of CNTs in agriculture. Investigations have shown that CNTs could induce phytotoxicity in plant cells and change the gene expression of plants. These studies indicated that comprehensive assessment and understanding of the potential risks of the application of CNTs in agriculture are critical to achieving the goals of “nano-agriculture.” For example, a recent study proved that a rice autologous transporter can reduce the accumulation of a highly toxic metalloid, arsenic, in the grain. However, to the best of our knowledge, the effects of CNTs on the enrichment/depuration of contaminants in crops are unclear, and more importantly, the permeability of CNTs in intact mature plants as well as the translocation of CNTs within plants have not explored. If the CNTs can penetrate the cell walls of plants and translocate to the edible parts of crops, they will enter the food chain and cause a risk to human health.

Carbon Nanomaterials in Agriculture: Agriculture and fishing industry.

The MWCNT-coated quartz crystal microbalance humidity sensor can be used to monitor relative humidity over the range of 5-97% RH with a response and recovery time of about 60 and 70 s, respectively.23,24 Similarly, CNT based CO2 sensors can be used to monitor the concentration of CO2 within the greenhouse or controlled environment garden to achieve an optimal environment for plant growth. CNTbased pressure sensors can be made use of for uniform spraying of liquid fertilizer, insecticides, pesticides, and herbicides. CNT-based pH sensors are highly useful for maintaining proper pH balance of water quality for fishing industries (for growth of cultured fishes and shrimps) so as to avoid abnormality in fishinggrounds and hatcheries.

 

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Carbon Nanomaterials in Agriculture

Carbon Nanomaterials in Agriculture

 

From us, you can easily purchase nano products at great prices. Place online order and we will dispatch your order through DHL, FedEx, UPS. You can also request for a quote by mailing us at sales@nanoshel.com Contact: +1 302 268 6163 (US and Europe), Contact: +91-9779550077 (India). We invite you to contact us for further information about our company and our capabilities. At Nanoshel, we could be glad to be of service to you. We look forward to your suggestions and feedback.