Towards Sustainability: ‘Greener’ composites lead push to net zero

AT A GLANCE

• IFM researchers at Carbon Nexus are not only looking at new carbon fibres and composites but new, more sustainable ways of manufacturing them.
• Companies are increasingly seeking composite materials that strike a balance between economic growth and environmental responsibility.
• At Carbon Nexus, IFM researchers can develop and de-risk new fibre technologies faster – and at scale – than anywhere else in the world, according to Professor Russell Varley.

Like many countries, Australia is making an ambitious push towards a renewable energy future and embracing the prospect of net zero emissions. But for such a transition to succeed, establishing a sustainable composite manufacturing sector is crucial.

Composites are engineered materials made from two or more constituent components that produce a material with enhanced characteristics. Managing such materials is essential to enable and advance many sectors including energy, aerospace, automotive and construction.

At the Institute for Frontier Materials’ Carbon Nexus facility, Australia’s leading open-access carbon fibre research and manufacturing centre, Professor Russell Varley and his team are not only looking at new carbon fibres and composites but also eyeing new, more sustainable ways of manufacturing them. Drawing on their expert knowledge in organic and polymer chemistry, as well as materials science and engineering, they are demonstrating how industry can develop an idea into a tangible product.

“To reduce emissions and achieve a transition to net zero, we need new materials that enable renewable energy at a lower cost, but we must also embed sustainability throughout the manufacturing process,” Prof Varley says. “Carbon fibre is the ideal material to accelerate this transition.”

Companies on the precipice of change

The global carbon fibre composite materials industry, valued in 2021 at $US80 billion, is growing rapidly, driven primarily by wind power and the promise of hydrogen storage.

“Carbon fibre is a great enabler for a sustainable energy future,” Prof Varley says. “It can enable electronic vehicles and hydrogen because they require lightweight pressure vessels that can maintain the load. If the demand for this continues to grow at the rate it is, demand for carbon fibre will soon outstrip supply.”

Companies in need of such composite materials are already seeking a balance between economic growth and environmental responsibility – and they are turning to Carbon Nexus to help strike that balance.

“Our partners recognise the need to have investment across the entire value chain – from raw materials and semi-finished product to original equipment manufacturers and end users,” Prof Varley explains.

“It’s not simply about creating more sustainable carbon fibre but, instead, it is about looking at how the entire carbon fibre composites industry will transition to a net-zero emission future.”

According to Prof Varley, there is no better time for companies to take advantage of the unique facilities at Carbon Nexus, which has been developing new fibre technologies and processes at scale for more than a decade.

“With this facility, our researchers can develop and de-risk new fibre technologies faster – and at scale – than anywhere else in the world and create new sustainable composite components that will enable a sustainable future.”

Research to form the foundations of the transition

Carbon fibre manufacturing emits 23 times more CO2 than glass fibre manufacturing. And with the global market producing about 140,000 metric tonnes of carbon fibre in 2022, reducing emissions from the manufacturing process is an essential focus of IFM’s research.

New rapid oxidation methods are one possibility. Oxidation is an essential part of the carbon fibre production process; it removes volatile components and impurities from the precursor material, often polyacrylonitrile (PAN) or pitch, and stabilises it to prevent decomposing during carbonisation.

“By introducing rapid oxidation to the production process, you can significantly reduce energy consumption and improve the efficiency – essentially, we can radically increase the speed of manufacturing but still remain in control of the process,” Professor Varley says.

IFM has partnered with LeMond Composites to commercialise such technology – which enables reductions of 75% and 70% in capital expenditure and energy consumption per kilogram of output respectively. Carbon Nexus researchers are also investigating how waste can be introduced into the production process.

Carbon fibre production generates harmful waste gases. Researchers are exploring how to recover those waste gases and, instead, recycle the gaseous effluents into carbon nanotubes on carbon fibres. But as important as the manufacturing process is, what happens to the carbon fibre after its first life? How easily can carbon fibre be disassembled and recycled?

Carbon Nexus researchers have begun looking at vitrimers – a new family of resin systems that have the base chemistry and properties of thermosets while having the processability and recyclability of a thermoplastic. Using this technology, the team has created new carbon fibre composite materials.

“Like Lego, these vitrimers are designed for disassembly,” Prof Varley says. “They can be recycled, repaired, restored and they keep going – it’s the science of resource efficiency.”

Uncovering bio-based composite materials

Currently, bio-derived carbon fibre does not exist on the commercial market. However, researchers at Carbon Nexus have already demonstrated that it is possible to manufacture it at scale.

“It has been done previously using lignin/cellulose, but our recent work has shown for the first time that entirely bio-based carbon fibre can indeed be manufactured at pilot scale and carbonised continuously first via oxidation then via carbonisation,” Professor Varley says.

“We have manufactured 1K tow carbon fibre from lignin cellulose via a traditional continuous manufacturing process with good mechanical properties – a world first.’’

According to the Carbon Nexus team, bio-based composite materials also bring superior characteristics. As construction sites dominate city skylines, major catastrophes such as the London’s Grenfell Tower disaster highlight the need for more advanced structure composite materials.

Fibre reinforced polymer composite materials are already widely used due to their excellent strength-to-density ratio, stiffness, fatigue strength and corrosion resistance.

“Fire-resistant composites have many disadvantages from poor processability and properties, to being entirely derived from unsustainable petrochemical sources,” Prof Varley says.

“To tackle this, we need to turn to bio-derived raw materials. At Carbon Nexus, we have developed new fire-retardant resin systems which, in addition to having excellent mechanical and thermal properties, are also derived from sustainable biomass.”

Focusing on fire retardant vegetation and exploring their special microstructure to prevent fires, the research team used agricultural waste to develop a bio-based flame-retardant hardener for an epoxy system. Next steps are using this matrix for carbon fibre fabrication.

Carbon fibre key for high performance turbine blades 

Carbon Nexus partnered with Vestas, a Danish wind turbine company, in 2023 in a second round of projects to develop next-generation carbon fibre and composite materials for wind turbine blades that are sustainable, low cost and of high performance.  

The demand for more renewable energy at lower cost is driving the development of large turbine blades with high energy harvesting capacity, approaching rotor sizes of 200 m in diameter. However, with these larger designs comes increased materials challenges that require solutions during their manufacture, their service life and even end-of-life. 

The research team led by Prof Russell Varley and Dr Claudia Creighton explores new strategies to solve the challenges of improving the compression properties of carbon fibres and their composites and creating a high-value second life for end-of-life wind turbine blades.  

After the initial breakthrough towards improving the compression strength by tailoring the carbon fibre microstructure and chemistry of the matrix resin, the team has been continuing to work on the optimisation, verification and scale-up of the most successful outcomes. 

This article was originally published in the 2023 IFM Annual Report.