Carbon fibre is strong, light and resistant to corrosion, making it ideal for composites used in a variety of products. Think of wheelchairs, bikes, buses, construction materials and more. Unfortunately, it's expensive to produce.
That's a problem three researchers in the University of Alberta's Faculty of Engineering — Cagri Ayranci, Kevin Hodder and Zhi Li — are trying to solve by making use of a plentiful byproduct of oilsands mining.
The current high price of carbon fibre is due to the relative rarity of the feedstock that goes into its making and the technology needed to process it for use in consumer goods. But there is something called asphaltenes, which are derived from bitumen, that Alberta has aplenty. Ayranci, Hodder and Li are setting their sights on turning asphaltenes into a viable, inexpensive new feedstock for carbon fibre. If they are successful, using asphaltenes will reduce the environmental impact compared with traditional feedstock sources for carbon fibre, which come from agriculture and forestry.
All three of their approaches have been successful in a lab setting. Now they're working to see whether the lab results can be scaled up for commercial use.
The projects are part of the Alberta Innovates Carbon Fibre Grand Challenge, a $15-million, three-phase competition to spur ideas to make Alberta bitumen-derived carbon fibre at a commercial scale. The challenge is part of the Bitumen Beyond Combustion strategy.
"These vast reserves of bitumen are the building blocks to create new low-carbon opportunities throughout Alberta," said Laura Kilcrease, CEO of Alberta Innovates.
Ayranci, Hodder and Li have earned three of 12 spots in Phase 2 of the competition and garnered more than $2 million in funding from the Clean Resource Innovation Network and Alberta Innovates. Three of the 12 teams will move on to Phase 3, which will include development and demonstration of a production process.
Cagri Ayranci: Apply what you know
Ayranci might not be the first person you'd imagine working with oilsands byproducts. His students call him a tree hugger because he normally works on natural products including lignin, a byproduct of the pulp and paper industry and a potential feedstock for carbon fibre production.
"We were taking the lignin and converting it into carbon fibre," Ayranci said. Asphaltene and lignin are very different products, he said, but they have similarities in terms of the chemistry: very low molecular weight and a very complex chemistry and molecular structures. "And we understood how to process these challenging materials," he said.
Ayranci is calling on his background in braided composite materials, used in a variety of applications including non-metallic rebars with carbon fibres in them used in aerospace and automobiles. "Different types of carbon fibres can also be used in supercapacitors in batteries and so on," he said.
By the end of Phase 2, Ayranci predicted the team — which includes Jason Carey, Mark McDermott and Tian Tang — will be experts in these processes and techniques and will have demonstrated that they are readily transferable. "We are trying to achieve a goal to provide something good, particularly for Alberta."
Ayranci is an associate professor in the Department of Mechanical Engineering. His project is "Towards Large-Scale Unconventional Micro-meter Diameter Carbon Fibre Production."
Kevin Hodder: 'It's like a hot glue gun'
When we burn fuel in our cars, we want it as clean as possible, and that involves purifying crude oil and removing asphaltenes, leaving brittle asphaltenes, said Hodder. "But then we have this abundance of asphaltenes with nowhere to go. This project is a challenge to make it a value-added product."
Together with teammates Robin Hamilton, David Scott and Jeff Stryker, Hodder is processing carbon-based asphaltenes through a device he likens to a hot glue gun. By processing the asphaltenes (which are made up mainly of carbon, hydrogen, nitrogen, oxygen, sulphur and trace metals) with electrolysis and thermal energy, Hodder said the asphaltenes transform and can be extruded as fibre. His team has demonstrated proof of concept and is now looking at the appropriate equipment to help scale it up.
What motivates him is imagining some of the products that would be possible.
"If you imagine wind turbine blades, for example, make them out of metal and they're really heavy. It takes a lot of power to move them," he said. "As we think about it, more uses come up."
Hodder said even if he and his team don't advance to Phase 3, they will be ready to commercialize their concept once this phase is complete.
Kevin Hodder is a research associate in the Department of Civil and Environmental Engineering. His project is "Producing a Mesophase Precursor via Electrochemistry and Induction Heating to Produce a Superior Carbon Fibre From Alberta Oilsands Asphaltenes."
Zhi Li: A fibre to fill a niche
Li's background is as a chemist. "So I know this kind of molecular structure — asphaltene molecular structure — compared to the typical carbon fibre," he said. Rather than a typical linear molecular structure, an asphaltene molecule is bigger and has a kind of connected multiple ring structure. "You have to align this molecule properly, otherwise you cannot get good mechanical performance," he said.
Li's team includes researcher Ken Cadien, a professor in the Department of Chemical and Materials Engineering, who has experience bringing products to market. They were able to make ultrathin carbon fibre by applying an electrical field to help the alignment of the molecular structure. Now they want to improve the mechanical strength of the fibre.
"We're starting to look at it to improve the screening process and the pretreatment of the asphaltenes to get some high-performance fibre," Li said.
Li hopes to wind up with a kind of carbon fibre that will fill a niche, reinforcing other materials. "People are kind of fascinated about carbon nanotubes with a diameter of several nanometres, but the length of carbon nanotubes is just micrometres to a maximum of tens of micrometres." Simply put, a nanotube is a nanoscale material that has a tube-like structure and might have the potential to act as a short-range reinforcement. But the nanotubes are not long enough to reinforce material in the same way as linear carbon fibre, which has a diameter of about seven micrometres and can typically be cut into lengths of six millimetres.
It's a big gap in application and functionality, he said, to bring down the diameter from several micrometres to several nanometres. "So, if we can get a small fibre with a diameter of a few hundred nanometres, which we can chop in whatever desired length, then we might end up creating a unique reinforcement material."
Zhi Li is an adjunct professor in the Department of Chemical and Materials Engineering. His project is "Carbon Fibres by Melt Electrospinning Alberta Oilsands Asphaltenes for Reinforced Composite, Energy Storage and Thermal Management."
