Plastics are so commonplace as to seem like wallpaper in the background, easily overlooked but ubiquitous. As the auto industry continues its drive to reduce vehicles’ carbon emissions, polymers are even more crucial through their weight-reduction advantages compared to other materials.
Indeed, the U.S. Department of Energy reports that reducing a vehicle’s weight by 10 percent can produce a 6-8 percent improvement in overall fuel economy, with a corresponding reduction in carbon emissions.
This is one reason why the auto industry is the third-largest user of polymers, after the packaging industry and the building and construction industries. According to Volkswagen, there are 39 different types of basic plastics used in the average car, and more than 70 percent of the plastic is derived from four main polymers: polypropylene, polyurethane, polyamides, and PVC.
Some of these parts have been around for a while. One example is the rubber axle bump stop. This is the part that cushions the impact when a car’s suspension bottoms out. In 1976, Denver Volkswagen shop owner Joe Markham found that his German Shephard puppy liked to use these bulbous rubber bumpers as chew toys, and he had the idea for the now-classic Kong dog toy.
New Volkswagens have many more uses for polymers than those old Beetles and Buses. One recent example is the development of a lightweight polypropylene to incorporate on the door frame of the Volkswagen Atlas.
“We were able to reduce the weight of the part while preserving its same characteristics,” said laboratory evaluation specialist Ellen Collins, who works in Volkswagen’s polymers laboratory near the company’s Chattanooga, Tenn. assembly plant.
A polymer is any long molecular chain made up of bonded chemical units, or monomers. These chemical chains are strong, resistant, and have a high tolerance for heat – making them useful in a variety of components throughout a vehicle.
“Polymers have improved all of our lives in many ways, but especially in vehicles,” said Collins, who may have overlooked their value for dog toys. “Unlike metals, you can directly mold them, which can make them more versatile and less expensive for the manufacturer. And, because they can be made quickly, they can go into production much faster than other materials, which can also help reduce the cost for the end-user.”
Collins and her team in VW’s polymer lab test, inspect, and approve these components to help ensure there are no defects, looking at characteristics such as the texture, mold, and grain. They also work closely with the company’s chemical compound suppliers to supply the right materials. “We challenge them with a ‘wish list’ of items we’d like to see developed,” she says.
Kong’s Markham had a similar wish list for material properties back in the ‘70s but lacked his own polymer lab. So, he turned to rubber experts in Germany to finalize the right chemistry and composition for a canine chew toy.
Plastics play a key role as the auto industry shifts toward electric drive systems because of the weight of EVs’ battery packs. “We have to incorporate lighter parts to help offset the weight of the car’s heavy batteries,” Collins said. “We believe that polymers are the future … and hope that all car companies are taking the same approach because the sooner they bring down the weight of their vehicles, the quicker we can work toward reducing our carbon footprint.”
And who knows what future product spin-offs could be inspired by emerging categories of chewable soft rubber parts?