Recycling composites for the automotive industry
In 20 years, the composites industry may have its own recycling system, like plastics and metals enjoy today. The lack is one reason composites cannot fully compete with these traditional materials.
The world’s annual carbon-fiber consumption stands at 30,000 tons, and recycling has been limited, for technological as well as economic reasons. Most waste goes to landfill.
But across the globe, businesses are investing in recycling technologies for carbon and glass fiber, with the goal of making recycling profitable. They are driven by promising markets; in particular, the automotive sector. In Europe, new vehicles must by law be 85-percent recyclable; 10 percent of the carbon-fiber reinforced plastics (CFRP) used in BMW’s i series, for example, is recycled material. Landfilling has been banned in Germany, a move that has spurred carmakers to reclaim as much carbon fiber as possible.
U.S., companies are working on extracting fiber from end-of-life components and on creating new composites. Mechanical, thermal and chemical technologies have emerged and are close to commercialization. Research continues to produce better recycling methods, which will one day mean a more sustainable composites industry. For the automotive industry, it could revolutionize the way its products are made.
It can be done
Last August, the Composite Recycling Technology Center (CRTC) in Washington State, with the U.K.’s ELG Carbon Fibre Ltd., unveiled a car seatback made from recycled carbon-fiber composites at the Automotive Lightweight Materials Summit in Detroit, successfully demonstrating manufacturability of the materials. The bucket-style seatback measured 24 by 19 inches. Its recycled fiber/nylon 6 resin was molded at CRTC in a hot compression cycle at 435 F.
Since its inception in 2015, the CRTC has been reclaiming uncured carbon-fiber scrap that would otherwise go to landfills, with a goal of recovering 1 million pounds yearly by 2022.
A contract signed this year with IACMI (the Institute for Advanced Composites Manufacturing Innovation) will let the CRTC pioneer ways to automate processing of this scrap and refashion it into new products. This will be a step toward eventual high-volume application, energy savings and carbon reduction. Creation of a composites recycling industry could follow.
Last year, ELG, with Gordon Murray Design, also of United Kingdom, produced iStream®, the world’s first affordable high-volume carbon fiber chassis. iStream® is made with 14 composite structural panels of Carbiso™M, ELG’s signature line of carbon-fiber nonwoven mats. ELG became a member of IACMI before partnering with CRTC.
Another company, Mallinda, has a new polymer that can be remolded at lower temperatures. Because it is easy to reshape, carbon-fiber car parts could be stamped out in less than a minute; currently the process can take hours. The material is placed in an organic, room-temperature solution, letting resin separate from the fibers, eliminating waste.
This year Mallinda won a $750,000 grant from the National Science Foundation’s Small Business Innovation Research program, which could take its material, called Pliashell, out of the laboratory and into production for the auto trade.
The company plans to develop a process for producing prepreg carbon fiber input materials, as well as methods for consolidating them into durable, multi-layer parts. If the Colorado firm can make the move into industrial production, sustainable carbon-fiber plastics might one day become a new standard.
Vartega, another Colorado-based recycler of advanced materials, has likewise come up with technology to provide low-cost carbon fiber for mass-market use in automobiles. Its method frees uncured carbon-fiber filaments for use in recycled nonwoven fabrics, yarns, thermoplastic pellets and 3D printing filaments.
The company aims to take thousands of tons of high-value carbon-fiber waste that would otherwise go to landfill, and salvage it for automotive and aerospace use. Vartega estimates it can improve fuel economy and reduce greenhouse gas emissions by millions of pounds each year.
Last September, IACMI announced a project that will generate technologies to provide Class-A surface appearance for auto body panels from a thermoplastic resin matrix reinforced with recycled carbon fiber.
The project, partnered with BASF, Oak Ridge National Laboratory and the University of Tennessee, will use end-of-life carbon-fiber material in a high-volume production stream that can save energy and cut carbon footprints. The process is expected to open up even more opportunities for carbon-fiber integration in the auto sector.
Cars may also be able to use plant waste that has been transformed into carbon fiber. When trees are used to make paper or ethanol, a residue is created, called lignin, which is a product found in plant cell walls. Currently, leftover lignin, like carbon fiber, also gets burned or tossed into landfills.
Attendees at the 254th National Meeting & Exposition of the American Chemical Society in August learned that lignin can be converted into carbon fiber, producing a lower-cost material strong enough to build car or airplane parts.
Fiber found in today’s cars and aircraft are typically made from polyarylonitrile (PAN), a pricey, non-renewable polymer. Fiber with lignin would be cheaper and more sustainable. Such fibers could, researchers say, be used as internal car parts, castings, bumpers or tire frames.
Though increased use of recycled fiber may be on the horizon, production costs remain high. As a material for cars, carbon fiber currently costs 20 times more than steel and 10 times more than aluminum, according to research from Jaguar Land Rover.
It is also difficult to break down. To make a strong, lightweight material, carbon fiber is combined with a plastic polymer resin, a wasteful manufacturing process. Carbon fiber cannot simply be melted down and reformed, like aluminum. Most polymers will not melt and must be burned off or chemically dissolved to reclaim the fibers.
So it is no surprise that nearly 30 percent of all fiber goes to waste as manufacturing scrap, is sent to landfills or incinerated at high heat, incurring even more energy costs. The U.S. State of Washington estimates that over two million pounds of carbon fiber is sent to landfills every year.
A February 2017 report from the environmental charity Green Alliance listed carbon fiber as one of several materials that could create waste problems in the future unless something is done to produce end-of-life solutions and transform it for reuse.
A final snag is carmakers’ reluctance to embrace new materials; 50 years of traditional, carbon-fiber chemistry and development will not change overnight. But research continues. Manufacturers are spurred by the knowledge that rescuing carbon fiber from landfill and applying it to cars could cut the average auto’s weight in half and improve fuel efficiency by 40 percent.
Written by Joshua Jampol
Joshua Jampol is an American writer, journalist and broadcaster. He has over 30 years’ experience on a variety of industrial and high-tech topics.