Nanocomposites dubbed `next big thing' Finding innovative ways to raise fuel economy while cutting costs and still meeting consumer demands could prove difficult for automakers, but a family of thermoplastic olefins (TPOs) using a new type of filler material, offers one solution: weight reduction.
Putting everyday cars and trucks on a diet usually drives up costs and forces sacrifices in performance and desirability. That's not the case with nanocomposites.
Made with submicron particles of smectite clay engineered on the nanometer (10 superscript -9m) level, TPOs that incorporate nanocomposites have better engineering and performance characteristics than traditional macro-sized reinforcement materials like talc, mica and glass-fiber, yet they're lighter and cost less.
"Not everyone realizes how significant (nanocomposites) are," says Bill Windschief, director of Montell Poly-olefins' North American automotive business group.
In 1997,Corp. formed a partnership with plastics supplier Montell to develop nanocomposites for automotive applications. Since then the two have met with much success according to Bob Ottaviani, manager of advanced polymer materials at GM's Materials and Processes Lab.
Industry-leading research produced two types of nanocomposite plastics: a mold-in color nanocomposite and a paintable-grade plastic suitable for body panels.
Mr. Ottaviani declines to speculate which models would be the first to sport nanocomposite materials, but he does reveal the new material would be most widely used as body cladding.
Ultimately, consumers can also expect GM to use nanocomposite body panels and interiors. Conceivably, Saturn cars, GM's plastics showcase, will eventually wear nanocomposite panels, but Mr. Ottaviani says GM will seek other applications first.
"I was hoping we'd have something by now, but it's not a simple process to get new materials down the pipeline," he says.
Both GM and Montell expect nanocomposites to appear on the market soon.
"We're very, very close to seeing the first polypropylene-based nanocomposites on cars," Mr. Windschief says. "It's a product that's about to emerge."
The technology has been slow moving through GM despite positive testing results that show few signs of faults. "The performance and molding characteristics don't point to any significant problems," Mr. Ottaviani says.
Tiny nanocomposite filler materials provide greater stiffness with less material than talc, mica or glass-fiber because of the way the particles of clay interact with the polymer matrix of the base polyolefin material. And less material equals less weight and lower costs. Montell claims cost savings of 10 to 20% per part.
"It should be the next big thing," Mr. Ottaviani says. Nanocomposites offer a 20% weight reduction from traditional fill polypropylene plastics. The weight savings are even greater when compared to other polymers like polyurethane. And nanocomposites are 50% lighter than steel.
Nanocomposites "could account for a significant amount of weight savings." Mr. Ottaviani says the lightweight plastic could help GM raise mpg a notch, "a penny here and a penny there, and it starts adding up."
Today's vehicles use about 200 to 250 lbs. of plastics. Of that, about 25% or 62 to 65 lbs., are conventional poly-propylene plastics, which could be easily replaced with nanocomposites.
The lower costs, higher strength and lighter weight make it appealing, but other properties like dimensional stability, the ability to maintain its shape over extreme temperatures, and a resistance to warping, make it practical and versatile. These characteristics also will allow designers more freedom when working on new products.
"Nanocomposites bring to designers a product that will help them engineer more performance at a lower cost," says Jim Keeler, innovation program manager at Montell.
While GM and Montell forge the way in development of smectite clay nanocomposites, DaimlerChrysler is "looking one step beyond that," says Dave Vesey, supervisor of plastics, composites and textiles.
"DaimlerChrysler is looking at other nano-materials for fillers besides clay, and what kind of performance characteristics other materials could have."
DC Senior Manager of Organic Materials Rick Gutowski says that when he first read about nanocomposites a few years ago, it was like living the scene from The Graduate when Dustin Hoffman is told plastics are the future. He says DC is at the beginning of the process, but the future's in nanocomposite materials.
DC engineers say they don't have nanocomposite products in the pipeline for the next three years, but they are working on combining nano fillers with traditional macro fillers to reduce weight and provide added strength. The main problem, Mr. Vesey says, is material processing costs. He says making nano-fillers is expensive, and while they offer cost, weight and performance opportunities, the economies of scale aren't there. As far as clay-based nanocomposites, DC is taking a wait-and-see position.
"We see (nanocomposites) as an opportunity, and we're looking at it closely."