Aerogels: Moving from Outer to Inner Space
Forget about carbon fiber, Kevlar, and all of the über composites that have been vying for interior supremacy since the turn of the century. Each promised lightweight and incredible strength but fell victim to high cost and specialized production techniques. And while intensive development has reduced cost and increased throughput, it may be a case of too little too late. High-volume, competitively priced aerogels are on their way.
Stephen Steiner says those who have heard of it (1) probably have because of its application on the Space Shuttle and (2) “think of something wet and wobbly like Jell-O.” But, he points out, the aerogel in the Space Shuttle tile application was actually made with silica and far from being wobbly, it was brittle. That notion caused the president and CEO of Aerogel Technologies in Boston, MA, and his team to trademark the word “Airloy” for its new class of advanced aerogels. Unlike traditional aerogels, Airloys can be made up from ceramics, polymers, carbon, metals and carbides, either separately or together. “Plus,” Steiner says mischievously, “the name was six letters, two syllables, and the dot com was available…” (aerogeltechnologies.com).
Though Aerogel Technologies is working with Ford to test lightweight Airloy engine covers with superior sound- and heat-absorption properties, it’s the company’s work with Airbus that shows the promise of aerogels in interior applications. One Airloy under evaluation is about 12 times lighter than a typical plastic, 50 percent better at thermo-insulation than Styrofoam or mineral wool, 20 to 100 times more sound absorbent than typical materials, and is both non-flammable and machinable. For aircraft, it eliminates the bags of pink fiberglass insulation attached to today’s panels whose properties degrade as they irreversibly absorb moisture over time, does not require application of a fire retardant, and should allow the cabin walls to more closely conform to the shape of the fuselage for greater room for both passengers and their luggage.
This same idea can be applied to vehicle door panels, with the panel either thermoformed and machined out of a single Airloy, or created by combining a thermoformed panel bonded with a semi-structural carrier made from another Airloy, composite, or plastic. “We can color impregnate the Airloy, plus add texture and add soft-feel materials, depending on the application needs,” says Steiner. “Which aerogel is chosen for an application,” he says, “comes down to what you are solving for in the equation. Is it weight, sound absorption, strength, thermal performance, or some combination of them all?”
No matter which direction the auto industry goes — battery, internal combustion, or hybrid power — Steiner believes that the unique properties of aerogels will make them contenders. “I think we’re at a massive inflection point in terms of material needs and properties,” he says, “especially as regulations demand greater efficiency, customers demand more space and quiet, and engineers put more in a smaller package.” For example, an electric vehicle requires that the passenger compartment remain insulated from the battery pack while it is heated and cooled, a greater range of sounds are absorbed, and that there be a fire break between the battery and passenger compartment. “With the right Airloy,” says Steiner, “you can create a panel that accomplishes this while also acting as the floor structure. It could be sandwiched between pre-preg fiber composite sheets or combined with steel or aluminum.”
Similarly, in an internal combustion or hybrid vehicle, Airloys allow coolant lines to run closer to the passengers for improved packaging and reduce noise from both the road and the powertrain. In addition, says Steiner, “Headliners would be a perfect use for aerogels, using the material’s ability to attenuate heat and sound, while also providing a thin, lightweight, strong, and stable structure. An electrically conductive carbon formulation would create a massive speaker with 1,000 times the sound reflectivity, and let you put the sound exactly where you want it.”
Seats are another area of study, driven by the need for lightweight chairs in aviation and automotive. Airloy panels and structures could reduce seat mass for conventional designs, and even enhance the capabilities of lightweight concepts like Gordon Murray Design’s iStream seat. That application would replace the fiberglass or recycled carbon fiber composite sandwich panels with Airloys while enhancing noise attenuation, strength, and weight reduction. Aerogels also would allow the use of foams that do not make the grade, according to Steiner, by “wrapping a thin Airloy film or fiber around a non-compliant foam so it would comply with burn certification standards.” That, however, is in the future.
Aerogel Technologies, now in its eighth year, is only just past the period where existence is defined by small samples, equally small customers, and experimental formulations. In the material sciences, going from chemistry to a new product and new markets typically takes 11 to 18 years before there’s a return on investment, which can lead to its own frustration in a world of instant gratification. “I watch Shark Tank, and people are getting the dumbest stuff funded when we’re here making a legit, non-vaporware, revolutionary material platform that can’t get people onboard fast enough,” Steiner laments. Unlike most of the contestant on that TV show, however, Aerogel Technologies is in pilot production, and working with industry partners on real-world applications. Moving forward from there, it appears, is only a matter of time.
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