LANSING, MICH. — Microscopic in size and forged from a mud slurry of silted clay, nanocomposites seem an unlikely choice to become the next shining star of the plastic resin world.
But with a new boost from General Motors Corp., nanocomposites could play a leading role in cars and trucks as soon as the year 2000. All this for a highly unusual additive dating back to prehistoric times that has virtually no track record in resins.
Montell Polyolefins — a top producer of polypropylene-based automotive resins — is working with GM to develop the first commercial family of thermoplastic olefins using the minuscule additives.
GM, a tough customer to please at times, sang its praises during a news conference Dec. 3 at Montell's Automotive Technology and Development Center in Lansing.
The carmaker expects to use nanocomposites soon for a variety of plastic interior and exterior parts, said Elio Eusebi, head of the polymers department at GM's research center in Warren, Mich.
``We think we can use this now in the parts we make,'' Eusebi said. ``We've done all the testing and know this can work well. We want to get a jump on nanocomposites before the rest of the industry catches up.''
While the auto industry gets its feet wet with the clay material, the packaging industry also may be beckoning.
Nanocor Inc., a subsidiary of chemical and minerals firm Amcol International Corp. of Arlington Heights, Ill., has made a scientific breakthrough with nanocomposites, said Amcol Chairman John Hughes.
The research firm is working with an undisclosed resin supplier to develop new specialty nylon and ethylene vinyl alcohol barrier materials using nanocomposites, for plastic beer or soft-drink bottles, Hughes said.
``Nanocomposites are a very big and very promising field,'' said Hughes, head of Amcol, which recorded $477 million in 1997 sales. ``Even recently, nobody was quite sure if this was real. Now, we know it is real.''
The material comes from an unlikely source: volcanic ash that settled in sea water between 45 million and 60 million years ago. Both Nanocor and Southern Clay Products Inc., the Gonzales, Texas-based firm working with Montell and GM, mine smectite clay compounds from that silted ash.
Southern Clay develops nanocomposites at plants in Gonzales, Texas, and Colony, Wyo., where the ash first was deposited in the Mowry Sea, which once covered most of the state. Nanocor takes its clay from sea water near its plant in Aberdeen, Miss.
The clay's ability to form in layered sheets makes it a good reinforcing material, said Theo Zwygers, technology director of Montell's automotive center. The substance disperses well in TPOs and provides better impact resistance and stiffness than typical talc mineral-filled resins.
Less than 5 percent of nanocomposite is needed with a standard TPO resin for an exterior body panel, Eusebi added. In contrast, many current TPO concoctions use about 25 percent talc.
That would make such potential applications as plastic fenders or quarter panels 30 percent lighter than they are with TPO materials. By using fewer additives, the TPO also is 50 percent stiffer and does not expand or contract as readily under severe temperatures, Eusebi said.
Nanocomposites cost more than current resin additives, said William Windscheif, sales and marketing director for Montell's automotive business group in Troy, Mich. Yet, because less of the additive is needed than with talc, the overall material price could be lower, he added.
GM, working with Montell and Southern Clay, plans to validate the material's performance during the next 12 months, Eusebi said. If all goes well, the next step would be its use commercially for the first time in North America.
Prototypes of an exterior quarter panel and an outer door skin have been made using the additive. Eusebi stressed that any application, including interior door panels, or instrument panel covers and substrates, is fair game.
Japan has been ahead of the curve in nanocomposite research. In the early 1990s, Toyota Motor Corp. became the first carmaker to use the additive, putting it into nylon for timing-chain covers, Hughes said.
Solvay Engineered Polymers, a competing automotive TPO provider, is exploring the use of nanocomposites with its resins, said Pete Perron, vice president of technology. An alternative considered at Solvay is an additive made from carbon instead of the ash-originated clay, he said.
``You have to be careful,'' Perron said. ``The area has definite opportunities, but its advantages can be blown out of proportion. Where there's a place for it, we'll use it.''
Because the substance can be divided finely across a surface, it performs well in stiffness and impact resistance, said Robert Eller, a plastics-industry consultant with Robert Eller Associates Inc. in Akron, Ohio.
Yet, firms have had difficulty incorporating it into resins until now, he said.
And nanocomposites have not been proven in a conventionally painted exterior auto part that must go through a paint oven at more than 400° F, he said.
``There's been a question whether you'd get the same physical properties,'' said Eller, who is preparing an exterior auto-parts study. ``But [Montell and GM] seemed to have solved some of the problems.''
The possibilities could go beyond current TPO-based parts to include interior components made of other plastic resins or even under-the-hood parts, said Donald Drummond, vice president of automotive and industrial sales and marketing for Montell North America in Wilmington, Del.
``You don't need a large quantity to get good reinforcement,'' he said. ``Why not shoot for parts that we haven't done before?''