TAGS: Graphene / Graphene Oxides Polymer Reinforcement
Graphene is a single layer or monolayer of carbon atoms, tightly bound in a hexagonal honeycomb lattice. It is an allotrope or variation of carbon in the form of a plane of sp2-bonded atoms or two covalent bonds at 120° angles with a molecular bond length of 0.142 nanometers.
2D materials are nanomaterials that can be broadly classified by the total number of their nanoscopic dimensions. If only 1 dimension is nanosized, it would be a 2D material resembling a large, but very thin sheet like a piece of paper, described as follows:
Number of
Nanoscopic Dimensions
|
Classification |
Example |
| 0 |
Bulk |
Anything you can see by eye |
| 1 |
2D (nanosheet) |
Graphene |
| 2 |
1D (nanotube or nanowire) |
Carbon nanotube |
| 3 |
0D (nanoparticle) |
Quantum dot |
Graphene is the leading 2D material versus other nanomaterials visually compared as follows:
2D Graphene Sheet (L), 1D Carbon Nanotube (C), 0D Quantum Dot (R)
Plastics Institute of America
2D Graphene and Other 2D Material Technologies
Structure of Graphene
Graphene, as mentioned, is a covalently bonded hexagonal lattice of carbon atoms just one atom or 0.14 nanometers thick. It is a semi-metal with its conduction and valence bands both touching.
Graphene's unique band structure means that electrons move through it at extremely high speeds or approximately 1/300 the speed of light, giving it fascinating properties, such as unparalleled electrical and thermal conductivity. Optically transparent graphene absorbs only 2% of incident visible light and has the highest tensile strength of any material.
A single monolayer of graphene, roughly 0.3 nm (nanometers) thick, would be able to support the weight of a football. It is also so dense that not even helium, the smallest gas atom can pass through it. The surface area of the material is the largest known for its weight. It is stronger and stiffer than diamond yet can be stretched by a quarter of its length like rubber.
» Explore the Commercially Available Graphenes!
Structure of Boron Nitride
Boron nitride is structurally identical to graphene but has boron and nitrogen atoms in place of carbon. In contrast to graphene, boron nitride is a wide-ranging insulator.
» View All the Commercially Available Boron Nitrides!
Other 2D Material Technologies
Graphene has dominated 2D material developments since its 2004 discovery. Other promising 2D material technologies include the following:
-
Transition Metal Dichalcogenides (TMDCs) —
Transition metal dichalcogenides commonly called TMDCs have the chemical formula MX2, where:
- M is a transition metal, such as molybdenum (Mo) or tungsten (W) and
- X is a chalcogen or an element from Group 16 of the Periodic Table, such as sulfur (S), selenium (Se) or Tellurium (Te).
Molybdenum Disulphide (MoS2) (L), Tungsten Ditelluride (WTe2) (R)
Bulk TMDCs are van der Waals materials with each layer being three atoms thick, consisting of the metal layer sandwiched between two chalcogenide layers. TMDCs are finding use in semiconductor manufacturing systems where abrasion-resistant, electrically conductive surface materials are required.
- Phosphorene —
It is a single layer of black phosphorus, a layered, stable variation of elemental phosphorus. It is a direct bandgap semiconductor with a puckered honeycomb structure. The bandgap can be tuned throughout the visible region by stacking layers on top of each other. It has good charge mobility, therefore making it suitable for optoelectronic devices and transistors.
Phosphorene or 2D Black Phosphorus Honeycomb Structure
- Xenes —
Monolayers of silicon, germanium, and tin are collectively known as Xenes and follow the graphene naming convention. They have a hexagonal structure similar to graphene but are buckled to varying degrees.
Silicon (L), Germanium (C), Tin (R) Buckled Hexagonal Xene Structures
While still very much in their infancy, potential applications range from electric field-effect transistors to topological or surface tailored insulators. Recently bismuth Xenes are under development and show potential for magneto-electronic enclosure applications, particularly for military lightning strike protection.
2D Graphene Material Plastic Resin Systems
Graphene plastic resin system development is currently focused on by end-use product developers. They use an array of graphene material forms, such as:
-
Powders,
-
Flakes,
-
Nanoplatelets,
-
Nanoribbons, and
-
Lattice structures
Compounding techniques include:
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Single and twin-screw compounding,
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Dispersion,
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Masterbatch,
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Rubber banbury and continuous mixing,
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Aqueous and solvent coating mixing,
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Hot melt adhesive dispersion, and
-
Spray coating solutions
Typical plastic resin systems used with graphene include the following:
| Thermoplastics |
Thermosets |
Rubbers |
|
|
|
|
Vorbeck Materials Group’s Vor-x Graphene Sheet
Vorbeck Materials Group’s Vor-x, a proprietary form of
graphene containing functional groups, represents a historically relevant as well as ongoing breakthrough entry into the conductive polymer additives market. The functionalized graphene allows compatibility to be ‘tuned’ to a specific plastic resin matrix, or allows specific material properties to be enhanced.
Vor-x graphene layers are entirely disassociated, and due to their wrinkled morphology, individual sheets do not reaggregate, ensuring good dispersion and handling. Compounding Vor-x masterbatches into plastics is much less difficult than a 1D Carbon NanoTube (CNT) masterbatch material. Vor-x yields conductivities well beyond anti-static and into the conductive range.
Transmission Electron Microscopy Image of a Vor-x Graphene Sheet, Showing the Material’s Wrinkled Morphology (L);
Electrical Conductivity of Natural Rubber with 4% Vor-x Compared with the Same Rubber Loaded with 40% Carbon Black (R)OCSiAl's Graphene Nanotube Concentrate
Elsewhere, the U.S. nanotechnology company
OCSiAl has commercialized an electrically conductive (EC) graphene nanotube concentrate called
Tuball™ Matrix 801. It brings permanent and consistent EC capability to a range of compounds based on:
Other 2D additive materials beyond graphene, such as Boron Nitride, Transition Metal Dichalcogenides (TMDCs), Phosphorene, and Xenes are still in early to very nascent stages of compounded plastic resin development, but will evolve further with the above outlined plastic resin systems in the future.
2D Graphene Market Size and Trends
Graphene market size is valued at around 35 million dollar in 2020, and the industry will register over 35% CAGR (Compound Annual Growth Rate) through 2025. This translates into an average 200,000 pounds of graphene additive material in 2020 at an average cost of 175 US dollar per pound within a range of 150-200 dollar per pound.
The ever-expanding global
electronics and semiconductor industry is considered the main market driving force behind sustained growth in the graphene marketplace. Graphene is 220 times stronger than steel and is relatively speaking tougher than diamond.
- In addition, it is a superior conductor of heat and electricity and is growing rapidly in applications around memory chips as well as screens in mobile phones and computer laptops.
- It is generally used in a combined dual-layer form to further enhance its durability, strength, conductivity, and toughness.
As a result of increased global consumer purchasing power, huge growth potential lies ahead for consumer electronic end-use applications, such as
computer tablets and
mobile phones that in turn will drive growth in the graphene market for transparent conductive surface materials.
Graphene transmits 97% of visible light through its thin, tough surface layer. In turn, this makes solid or coated graphene surfaces highly transparent that in concert with its exceptional conductive and heat-carrying properties creates opportunities in next- generation electronics, such as batteries and solar panels. For example, a transparent tactile sensitive graphene layer and a photovoltaic cell whose underneath can be integrated into a prosthetic hand can react to both static and dynamic stimuli visually described as follows.
Graphene Layer and Photovoltaic Cell
Additionally, graphene is rapidly gaining popularity in the
automotive, aerospace and defense industries. It is light in weight and possesses exceptional strength and toughness. Growing demand for lighter and safer vehicles and airplanes will offer tremendous opportunities for the product to be used not only for use in conductive, functional textile, sensor coatings and molded housings, smart adhesives, cooling and heating system components, but also as an emerging structural reinforcing additive in thermoplastic and thermoset composite materials as visually described in the automotive example (and applicable in analogous airplane systems) below.
Graphenes in Automotive (T) and Aerospace (B) Applications
Furthermore, the automotive industry is heading towards a production volume of over 100 million global vehicles in the 2022 model year. Concurrently there remains a growing concern for
safety, fuel-efficient vehicles. Also, growing attempts to strengthen vehicle structures as well as to improve the crashworthiness is creating an ongoing demand for graphene plastic compounds in the manufacturing of
greener and lighter automobiles and trucks.
For example, at a recent Geneva Motor Show, the Spain-based automobile manufacturer Spania introduced its first supercar, the GTA Spano, that heavily incorporated graphene into the car structure, which in turn reduced the overall vehicle weight that ultimately translated into reducing fuel consumption and emitting less greenhouse gases.
Other commercial end-user development driven graphene applications include the following examples.
Lightweight Graphene Modified ABS Crash Helmets (Catlike, Momo Design)
|
Graphene Modified Mineral Filled Nylon 66 Tennis Racquet Frame (Head) |
|
Graphene Modified Foamed Polypropylene Membrane for Headphones: Less Distortions,
Better Sound Quality, Good Heat Dissipation (Ora)
|
PLA Carrier for Modified Graphene Ink for RFID Biosensor Cartridge Reader. Drug Molecules Attach to Reader Targets (Nanomedical Diagnostics) |
|
PS Absorbing Modified Graphene Ink (Vorbeck Materials’ Crumpled Graphene; Graphene Energy)
|
Graphene Going Forward
Graphene's unique 2D structure means that electrons travel through it differently compared to most other materials via a so-called
atomic brick structure. One consequence of this unique transport phenomena is that applying a voltage to them, doesn't stop the electrons as in most other materials. To make useful applications out of graphene and its unique electrons for quantum computer development, it is critical to be able to tailor stop and control graphene electrons mechanisms within its atomic brick structure.
Graphene sensors have been tuned to
monitor food freshness and safety. Researchers tailored their new, printed on PET (PolyEthylene Terephthalate) sensors into tuna broth and monitored the readings. It turned out the sensors printed with high-resolution aerosol jet printers on a flexible polymer film and tuned to test for histamine, an allergen and indicator of spoiled fish and meat can detect histamine down to 3.41 parts per million.
German company Georg H. Luh is a market leader in
TC mineral additive products for heat management. Their technology is based on graphene nanoplatelets that enhance not only thermal but also electrical conductivity. There are two base grades namely:
-
GraphTHERM® – It delivers high thermal conductivity.
-
GraphCOND® – It has good thermal conductivity at very low filling rates that maintains high mechanical property performance.
These technologies are very useful for energy efficient, long duration LED (Light Emitting Diode) bulb bases.
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