Flash Joule Heating process recycles plastic from expired F-150 trucks into high-quality graphene for new cars.
Originally published by Reis News with permission from Reis University.
by Mike Williams
The part of the old car that has been converted to graphene can come back as a better part for a new car.
Rice University chemists are working with researchers at Ford Motor Company to convert plastic parts from “expired” compounds into graphene via the university’s heating process.
The average SUV contains up to 350 kilograms (771 lb) of plastic, which can end up in landfills for centuries without the need for a recycling process.
It is reported in the first issue of the new Nature magazine, Nachrichtentechnik.
The goal of the project, led by Rice chemist James Tour and graduate student and lead author Kevin Weiss, was to reuse this graphene to make improved polyurethane foam for the new compounds. Tests have shown that the graphene-enriched foam has 34% more tensile strength and 25% higher sound absorption at lower frequencies. This is by weight of only 0.1% or less of graphene.
And when the new car gets old, the foam can flash back into the graphene.
“Ford sent us 10 pounds of mixed plastic waste from an auto shredder,” Tour said. “It was muddy and wet. And we drove it, sent graphene back to Ford, and poured it into new foam compounds and did everything it was supposed to do.
“Then they sent us the new compounds and we flashed them and put them back in graphene,” he said. “It’s a great example of circular recycling.”
The researchers cited a study estimating that the amount of plastic used in vehicles has increased by 75% over the past six years to reduce weight and increase fuel economy.
Separating mixed plastic waste by type for recycling is a long-term problem for the auto industry, said Tour, and it’s made even more important due to potential environmental regulations for end-of-life vehicles. “In Europe, cars go back to the manufacturer, who is only allowed to bury 5% of the car,” he said. “That means they have to recycle 95% and that’s stressful for them.”
Much mixed plastic is burned, according to co-author Debora MielewskiTechnical Fellow in Sustainability at Ford, who has found that 10 to 15 million cars are shredded in the United States each year, with more than 27 million shredded worldwide.
“We have hundreds of different combinations of resin, fillers, and reinforcements on composites that make it impossible to separate the materials,” she said. “Each application has a specific load/mixture that meets the requirements economically.”
“These are not recyclables like plastic bottles, so they can’t melt and reshape them,” Tour said. “So when the Ford researchers saw our paper on heating plastics in graphene with a Joule flash, they reached out.”
Flash Joule heating is used to make graphene, introduced in 2020 by the Tour Lab, which is packages of blended crushed plastic and a coke additive (for conduction) between electrodes in a tube and radiates them at a high voltage. Suddenly intense heat—up to nearly 5,000 degrees Fahrenheit—evaporates other elements, leaving behind easily soluble turbostat graphs.
Rapid heating provides significant environmental benefits as the process requires no solvents and uses minimal energy to produce graphene.
To test whether or not mixed plastic can be converted at the end of life, Rice’s lab grounds shredder lint from plastic fenders, gaskets, carpets, mats, seats, and door panels from expired F-150 pickup trucks to a fine powder without washing or Pre-sort the components.
The tester flashed the powder in two steps, first at a low current and then at a high current in a Wyss heater specially designed for the experiment.
The powder heated at low current for 10 to 16 seconds produces a highly carbonated plastic that is about 30 percent of the original mass. The remaining 70% has been disposed of or recovered in the form of hydrocarbon-rich waxes and oils, which Wyss says can also be recycled.
Do you appreciate the originality of CleanTechnica? Consider becoming a CleanTechnica member, supporter, technician, ambassador – or Patreon sponsor.
Do you have a tip for CleanTechnica, would you like to advertise or suggest a guest on the CleanTech Talk Podcast? Contact us here.