At a recent conference, Ford Motor presented its innovative graphene-enhanced polyurethane (PU) foam that reduces noise in automobiles while also lowering their weight. The material was chosen as a finalist for the Polyurethane Innovation Award, given by the Center for the Polyurethanes Industry (CPI) during the conference. The foam is said to be used in all of Ford's North American vehicles.
One of the biggest challenges in developing the foam was dispersing a nanomaterial like graphene into a viscous polymer and keeping it from collapsing during mixing, said Alper Kiziltas, technical expert, sustainability and emerging materials at Ford.
XG Sciences provided graphene that was chemically compatible with the PU in sufficient quantities and at a reasonable cost, Kiziltas said. Eagle Industries, a tier-one PU moulder, was involved with processing the foam.
Polyols with graphene could not be processed like a typical additive, he said. To maintain graphene's properties, the material had to be processed differently. "Coupled with the needs of Eagle’s manufacturing process, a unique method of combining and dispersing the graphene with the polyol side of the foam was developed," Kiziltas said.
Ford's other challenge in developing the PU was conceptual. For new materials, it is commonly believed that an application will get better properties if it consumes more of the material. Counter-intuitively, Ford began lowering the concentration of graphene in the polyol, Kiziltas said. As the concentration fell, the resulting foam's performance improved.
Graphene now makes up less than 0.3% of the foam, he said. "We got really good mechanical, thermal and physical properties."
Formulating the PU with graphene was remarkably simple, Kiziltas said. It required almost no changes outside of the addition of graphene.
Other challenges were typical of the ones companies face when they introduce new materials.
One was cost, because customers are sensitive to prices. Ford had to make sure that the new foam would be at least cost neutral, Kiziltas said.
Also, because the foam is a new material, Ford had to ensure that it would meet or exceed requirements for the part, Kiziltas said.
Compression strength and modulus increased by about 20% when compared with foam made without graphene, he said. Heat deflection improved by 30%. The sound absorption coefficient increased by 25%.
Components made of the foam were over 10% lighter in weight, he said.
Automobile producers are eager to reduce the weight of their vehicles because they can travel farther on a tank of fuel, allowing them to emit fewer emissions.
Ford introduced the foam in 2018, and it is used in components such as engine covers, oil-pump covers and fuel-rail covers.
These covers are limited to internal combustion engines. However, Ford sees potential uses for the foam in electric vehicles (EVs).
It turns out that the white noise from engines conceals the rumble and squeaks that come with everyday driving. These annoying sounds are much more pronounced in electric vehicles since they lack internal combustion engines.
Ford's foam could be used in head liners, door panels and under the carpet to lessen the noise in electric vehicles, Kiziltas said.
Companies outside of the automotive industry are also inquiring about the foam, according to Kiziltas.