Did you know that the amount of plastic used in vehicles has increased by 75 percent in the past six years? This has led to the average SUV containing up to 350 kilograms (771 pounds) of plastic that could sit in a landfill for centuries.
Thankfully, researchers from Rice University were inspired to do something about this environmental disaster and created a method to turn the plastic part from “end-of-life” vehicles into graphene via a novel “Flash Joule heating” process.
The graphene is then processed into a type of polyurethane foam for new cars. Graphene-infused foam is well sought after due to its ability to increase the tensile strength of the vehicles by 34 percent and low-frequency noise absorption by 25 percent. All this with only 0.1 percent weight of graphene throughout the material! What’s more is the recyclability of the materials, with the old foam being able to be flashed back into graphene again.
This technique also dodges a big problem in the industry when it comes to recycling plastic from end-of-life vehicles: segregating different plastic types. “We have hundreds of different combinations of plastic resin, filler, and reinforcements on vehicles that make the materials impossible to separate,” said co-author Deborah Mielewski.
Flash Joule heating overcomes this problem as the method simply requires mixed ground plastic to extract the useful graphene product. A carbon additive for conductivity is also added to the plastic and electrodes run a high voltage through it. This all requires minimum energy to produce the desired graphene product and does not require any environmentally harmful solvents.
This sustainable innovation has been picked up by Ford, who was impressed by its practicality, substantial reduction in energy, greenhouse gas emissions, and water use when compared to other methods.
“Ford sent us 10 pounds of mixed plastic waste from a vehicle shredding facility,” lead author James Tour said. “It was muddy and wet. We flashed it, we sent the graphene back to Ford, they put it into new foam composites and it did everything it was supposed to do. Then they sent us the new composites and we flashed those and turned them back into graphene. It’s a great example of circular recycling.”
“When we got the graphene back from Rice, we incorporated it into our foam in very small quantities and saw significant improvement. It exceeded our expectations in providing both excellent mechanical and physical properties for our applications,” added Ford researcher Alper Kiziltas.
Source study: Communications Engineering – Upcycling end-of-life vehicle waste plastic into flash graphene