Jan. 29, 2002 — When the first round of the Davis Cup gets under way Feb. 8, nanotechnology will be working, literally, within the game.
null
Inside the tennis tournament’s official ball, the Wilson Double Core, a nanocomposite coating helps keep it bouncing twice as long as a conventional one.
null
The medley of nanoclay particles and rubber polymers developed by InMat LLC, in Hillsborough, N.J., that seals the inside of the Wilson ball is a commercial nanocomposite, a growing category of materials that fuse ingredients — typically a plastic or polymer matrix with inorganic nanoscale particles — to create new substances with unprecedented properties.
null
Nanocomposite powders, thin films, coatings and crystals promise to make products lighter, stronger, electrically conducting or heat-resistant. They may even lead to properties never seen before, such as the radar-absorbing qualities of (non-nano) composites found in the skin of stealth combat aircraft.
null
On the macro scale, an example of a composite material is concrete, which takes a binder — cement — and makes it stronger with reinforcing gravel. Back at courtside, a “graphite” tennis racket is also made from composite materials, though the carbon graphite fibers that make it strong and light are much larger than the nanoparticles in Wilson’s superball.
null
InMat’s Air D-Fense solution brings together butyl rubber polymers — commonly used for air-tight applications such as sealing tires or balls — with vermiculite, a natural clay that can slide off, or exfoliate, into single-molecule thin sheets.
null
At Cornell University, materials science and engineering professor Emmanuel Giannelis has been researching nanocomposites similar to InMat’s since 1987. “Think of these thin clay sheets as a deck of cards,” he explains. “If you laid the deck out, card by card, you’d be able to cover a very wide surface area. “
null
Now imagine multiple layers of such spread-out cards dispersed through a rubber matrix. The effect within InMat’s nanocomposite is a kind of hedgerow maze that greatly slows gaseous air molecules from diffusing out through the material.
null
InMat’s commercial trump card is a patented process for getting 1-micron balls of butyl rubber to intermingle with clay particles in a water-based solution, while keeping the clay “cards” in their thin, exfoliated state.
null
The method also keeps the proportion of clay particles to butyl rubber high so that as the material dries into a coating, the nanoclay cards fit into many slots in the rubber matrix to form a multilevel air barricade.
null
“What’s most special about our material is that it holds air yet remains flexible,” said Harris Goldberg, InMat’s president and co-founder. He noted that early efforts produced material that was too brittle, but that the company has developed proprietary techniques that allow the clay particles to block air while preserving the butyl’s rubbery flexibility. “Also, we do this 100 percent water-based, so no dangerous solvents are involved,” Goldberg added.
null
While InMat’s sealant has commercial potential for other types of balls such as soccer or basketballs, the tire industry is a natural next prospect. In fact, the company originated in 1996 as a joint development program between Hoechst Research and Technology and a major tire manufacturer.
null
Goldberg believes that InMat’s coating could serve not only as a better air sealant inside tires, but could also make tires lighter, cheaper and cooler running. “Most tires have a 1-3-millimeter layer of butyl rubber inside. Our coating is about 20 microns thick, so there’s potentially both a cost and weight savings,” he said. The industry spends about a billion dollars sealing tires with butyl, so the savings in material costs could be significant.
null
And lighter tires would offer better gas mileage. Goldberg also noted that a thinner coating that used less butyl rubber would make recycling tires easier and more environmentally friendly.
null
Cornell’s Giannelis considers InMat’s commercial success an important development for the fledgling industry. While nanocomposites have been investigated in labs for almost a decade, only now are companies learning how to make them with precision and in affordable commercial quantities.
null
For nanocomposites to become a bigger business, Giannelis believes, research must translate into affordable production processes for other polymers and thermoplastics such as polypropylene and polystyrene.
null
“This is a very real, affordable and adaptable technology that will make people money,” Giannelis said. “We can create very large changes in the properties of materials with very small quantities of very small inorganic particles.”
null
Related News
French firm hopes to get PR bounce out of nanotubes in tennis rackets