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.

composite crossection image

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.

layers inside a composite image

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 and tin layered composite image

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.

Further reading

Latest Graphene Composite news

Swinburne University and IIM announce graphene smart composites project

Sep 11, 2017

Imagine Intelligent Materials and Swinburne University have announced a collaborative six-month project aiming to develop graphene-reinforced smart composites. The composite will be able to report on the condition of large structures, and will have major commercial potential in the transport sector, including automotive and aerospace.

The project is supported by a $20,000 Seed grant from the university under a program, targeting “interdisciplinary projects that are aligned with the Swinburne research institutes’ external partnership and collaboration objectives”. It will combine expertise from experts in sensors, electronics engineering and aerospace manufacturing at the university.

Haydale announces proposed collaboration with Rogers Advanced Composites

Sep 06, 2017

Haydale logoHaydale recently announced that it has agreed heads of terms for a technical and commercial collaboration with Rogers Advanced Composites ("RAC”). RAC is developing a composites center in the UK, and this collaboration will aim to enable RAC to access Haydale’s extensive technical know-how in composites, polymers and resins and to incorporate the range of advanced graphene enhanced composites, developed by Haydale, into its existing and future projects.

RAC, which has roots in the marine and yachting world through its sister company Rogers Yacht Design, has built a strong reputation in the design and manufacture of advanced composite products. It is Haydale’s understanding that RAC is experiencing a strong demand for high quality composite solutions across a range of industrial sectors including marine, military and motor sport and that RAC is in the process of securing long term production contracts for an oil recovery project as well as several aerospace, military and motor racing projects.

The Graphene Catalog - find your graphene material here

Connecticut team designs a unique process for exfoliating graphene

Aug 31, 2017

Researchers at the University of Connecticut, assisted by ones from the University of Akron, have patented a unique process for exfoliating graphene, as well as manufacturing innovative graphene nanocomposites that have potential uses in a variety of applications.

The new process doesn’t require any additional steps or chemicals to produce graphene in its pristine form. “The innovation and technology behind our material is our ability to use a thermodynamically driven approach to un-stack graphite into its constituent graphene sheets, and then arrange those sheets into a continuous, electrically conductive, three-dimensional structure” says the lead scientist in the study. “The simplicity of our approach is in stark contrast to current techniques used to exfoliate graphite that rely on aggressive oxidation or high-energy mixing or sonication – the application of sound energy to separate particles – for extended periods of time. As straightforward as our process is, no one else had reported it. We proved it works”.

New graphene-enhanced non-liquid lubricant shows promise for various aerospace applications

Aug 24, 2017

Researchers at Purdue University have created a new type of graphene-enhanced non-liquid lubricant which reduces friction and wear. The suggested applications include air compressors for missile systems and more. The new liquid-free composite is made from a slurry of graphene, zinc oxide, and the polymer polyvinylidene difluoride.

Graphene-enhanced non-liquid lubricant shows promise image

The nanosize zinc-oxide particles allow the lubricant to stick to the metal surface, and the polymer binds the whole mixture together, said the team, which also explained that solid lubricants are needed for numerous applications such as air compressors, equipment used in the food industry, space vehicles, gear-and-chain mechanisms, fasteners found in high-temperature environments, and missile systems.

Graphene-fed spiders spin ultra-silk

Aug 16, 2017

Italian and British researchers have created a unique kind of material, produced by spiders that were "fed" with miscrosopic flaked of graphene and CNTs.

The scientists fed "special" water to three species of spiders. Dispersed within it were microscopic flakes of graphene, or carbon nanotubes. When silk was subsequently gathered from the spiders, it was found that the graphene/nanotubes had been passed into the fibers. As a result, its tensile strength and toughness were much higher than that of regular spider silk.