How polymers help make Volkswagen cars lighter, faster and more fuel-efficient

European model shown. Specifications may vary.

The role of plastics in the design and production of cars has never been more essential. To help meet the needs of modern cars, scientists and specialists at Volkswagen of America’s polymers laboratory near the company’s Chattanooga plant create innovative solutions to help make cars lighter and more fuel-efficient.

“Polymers have improved all of our lives in many ways, but especially in vehicles,” says laboratory evaluation specialist Ellen Collins, who has studied and seen the evolution of these advanced materials for the past decade.

The term polymer refers to any long molecular chain made up 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.

“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 explains.

The automotive industry is the third most important consuming sector of polymers after packaging and building and construction. On average, there are 39 different types of basic plastics used in a car and more than 70 percent of the plastic is derived from four main polymers: polypropylene, polyurethane, polyamides and PVC.

Volkswagen of America’s polymers laboratory in Chattanooga, Tn.

Collins and her team test, inspect and approve these components to help ensure there are no defects – for example, in 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.

These high-performance polymers are designed to be long-lasting can be found throughout the vehicle, from the car’s tires to its trunk. They can absorb energy in the event of car crashes and help minimize the harmful impacts to the car’s driver and occupants.

“Look at the evolution of the instrument panel. Originally, the dashboard was made of wood or metal. But, when they changed it to polymers, it started being referred to as a crash pad. Why? …Because it is softer and had protective padding, which can lessen the impact on the driver during an accident,” Collins says.

She explains that one of the lab’s main objectives is to help reduce the overall weight of a vehicle as much as possible without losing any capabilities. According to the Department of Energy, reducing a vehicle’s weight by 10 percent can result in a 6-8 percent improvement in overall fuel economy. It boils down to physics: The lighter the vehicle is, less power is required to get it moving and less energy is needed to maintain a constant speed and it thereby uses less fuel. The lighter various vehicle components can be made, the more flexibility designers and engineers have to add other technologies like electronic sensors and airbags while staying within weight goals.

One recent win the lab experienced was working with suppliers on producing 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,” Collins says.

Collins says the role of plastics in the design and production of cars has never been more important and expects the demand for polymers will grow over the next decade, thanks in large part to the increase of electric and hybrid vehicles. By 2025, Volkswagen is committed to reducing the carbon footprint of its global vehicle fleet by 30 percent compared to 2015 and aims to make the Volkswagen Group’s balance sheet CO₂ neutral globally by 2050.

“We have to incorporate lighter parts to help offset the weight of the car’s heavy [lithium] batteries,” Collins says. “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.”