What are composite materials?
Composite materials (also referred to as composition materials, or simply composites) are materials formed by combining two or more materials with different properties to produce an end material with unique characteristics. These materials do not blend or dissolve together but remain distinct within the final composite structure. Composite materials can be made to be stronger, lighter or more durable than traditional materials due to properties they gain from combining their different components.
Most composites are made up of two materials - the matrix (or binder) surrounds a cluster of fibers or fragments of a stronger material (reinforcement). A common example of this structure is fiberglass, which was developed in the 1940’s to be the first modern composite and is still in widespread use. In fiberglass, fine fibers of glass, which are woven into a cloth of sorts, act as the reinforcement in a plastic or resin matrix.
While composite materials are not a new concept (for example, mud bricks, made from dried mud embedded with straw pieces, have been around for thousands of years), recent technologies have brought many new and exciting composites to existence. By careful selection of matrix and reinforcement (as well as the best manufacturing process to bring them together) it is possible to create significantly superior materials, with tailored properties for specific needs. Typical composite materials include composite building materials like cement and concrete, different metal composites, plastic composites and ceramic composites.
How are composite materials made?
The three main factors that help mold the end composite material are the matrix, reinforcement and manufacturing process. As matrix, many composites use resins, which are thermosetting or thermosoftening plastics (hence the name ‘reinforced plastics’ often given to them). These are polymers that hold the reinforcement together and help determine the physical properties of the end composite.
Thermosetting plastics begin as liquid but then harden with heat. They do not return to liquid state and so they are durable, even in extreme exposure to chemicals and wear. Thermosoftening plastics are hard at low temperatures and but soften with heat. They are less commonly used but possess interesting advantages like long shelf life of raw material and capacity for recycling. There are other matrix materials such as ceramics, carbon and metals that are used for specific purposes.
Reinforcement materials grow more varied with time and technology, but the most commonly used ones are still glass fibers. Advanced composites tend to favor carbon fibers as reinforcement, which are much stronger than glass fibers, but are also more expensive. Carbon fiber composites are strong and light, and are used in aircraft structures and sports gear (golf clubs and various rackets). They are also increasingly used to replace metals that replace human bones. Some polymers make good reinforcement materials, and help make composites that are strong and light.
The manufacturing process usually involves a mould, in which the reinforcement is first placed and then the semi-liquid matrix is sprayed or poured in to form the object. Moulding processes are traditionally done by hand, though machine processing is becoming more common. One of the new methods is called ‘pultrusion’ and is ideal for making products that are straight and have a constant cross section, like different kinds of beams. Products that of thin or complex shape (like curved panels) are built up by applying sheets of woven fiber reinforcement, saturated with matrix material, over a mould. Advanced composites (like those which are used in aircraft) are usually made from a honeycomb of plastic held between two sheets of carbon-fiber reinforced composite material, which results in high strength, low weight and bending stiffness.
Where can composites be found?
Composite materials have many obvious advantages, as they can be made to be lightweight, strong, corrosion and heat resistant, flexible, transparent and more according to specific needs. Composites are already used in many industries, like boats, aerospace, sports equipment (golf shafts, tennis rackets, surfboards, hockey sticks and more), Automotive components, wind turbine blades, body armour, building materials, bridges, medical utilities and others. Composite materials’ merits and potential assures ample research in the field which is hoped to bring future developments and implementations in additional markets.
Modern aviation is a specific example of an industry with complex needs and requirements, which benefits greatly from composite materials’ advantages. This industry raises demands of light and strong materials, that are also durable to heat and corrosion. It is no surprise, then, that many aircraft have wing and tail sections, as well as propellers and rotor blades made of composites, along with much of the internal structure.
What is graphene?
Graphene is a two-dimensional matrix of carbon atoms, arranged in a honeycomb lattice. A single square-meter sheet of graphene would weigh just 0.0077 grams but could support up to four kilograms. That means it is thin and lightweight but also incredibly strong. It also has a large surface area, great heat and electricity conductivity and a variety of additional incredible traits. This is probably why scientists and researchers call it “a miracle material” and predict it will revolutionize just about every industry known to man.
Graphene and composite materials
As was stated before, graphene has a myriad of unprecedented attributes, any number of which could potentially be used to make extraordinary composites. The presence of graphene can enhance the conductivity and strength of bulk materials and help create composites with superior qualities. Graphene can also be added to metals, polymers and ceramics to create composites that are conductive and resistant to heat and pressure.
Graphene composites have many potential applications, with much research going on to create unique and innovative materials. The applications seem endless, as one graphene-polymer proves to be light, flexible and an excellent electrical conductor, while another dioxide-graphene composite was found to be of interesting photocatalytic efficiencies, with many other possible coupling of materials to someday make all kinds of composites. The potential of graphene composites includes medical implants, engineering materials for aerospace and renewables and much more.
The latest graphene composite news:
Tirupati Graphite has announced that its research center has developed a 'ground-breaking' graphene-aluminium (Al-Gr) composite, which reportedly exhibits significantly higher conductivity and strength properties over aluminium and could be used as a substitute for copper.
The specialist graphite and graphene producer said it was engaged with potential end users including a FTSE100 company for the composite’s potential use replacing copper in thermal, power and propulsion systems, providing significant environmental advantages owing to reduced weight.
A British engineering company called Viritech is working on an ambitious hydrogen-powered hypercar. Dubbed the Apricale, it is being designed primarily as a technical showcase for the company’s hydrogen fuel-cell technology and aims to demonstrate the advantages of hydrogen vehicles over electric powertrains. The hypercar will be sold in limited numbers for around £1.5 million (~$2 million).
In order to lower the weight of the Apricale’s hardware, it features graphene-reinforced hydrogen pressure vessels. It was explained that the hydrogen storage tanks form part of the structure of the chassis to reduce weight and cost.
Haydale has announced that it has been awarded funding of £138,549 (around USD$192,290) to develop hydrogen fuel cell tanks by the Advanced Propulsion Centre (APC).
To support the future of green automotive manufacturing and accelerate the UK's transition to net- zero emission vehicles, the Advanced Propulsion Centre (APC) has guided £9.4 million in public funding to 22 feasibility studies looking to scale up the industrialization of low-carbon emission vehicle technologies.
Haydale has announced that it has partnered with U.S-based 401 Tech Bridge to provide a HT200 Plasma Reactor and advanced materials support for their innovation ecosystem.
The HT200 Plasma Reactor will be utilized in the 401 Tech Bridge Advanced Materials and Technology Center, managed by the University of Rhode Island (URI), to support material commercialization efforts of Graphene Composites and other local composites and textiles-based businesses. This adds to 401 Tech Bridge's capability supporting its ambition to accelerate the adoption of new materials and support companies' efforts in developing new products.
First Graphene reports positive results from PureGRAPH wear line testing, enters MOU with Brazil's Gerdau
First Graphene has reported results from field testing of the PureGRAPH-enhanced bucket wear liner, which have reportedly shown an almost six times reduction in average abrasion loss compared with a standard polyurethane liner. The bucket wear liners were installed at a major iron ore producer’s load-out facility in the Pilbara of Western Australia, beginning in mid-2019. A standard wear liner and a graphene-enhanced ArmourGRAPH wear liner ran simultaneously in the same location for the 62-week period.
In addition, First Graphene has entered into a memorandum of understanding (MOU) with Brazil’s largest steel producer, Gerdau. The MOU is currently non-binding, and allows for the two companies to negotiate terms towards a binding agreement, which would establish an initial commercial agreement for distribution and collaboration.