Mute Room auditorium, designed by Beige/Thom Faulders
Photo courtesy of designer

So-called “memory foams” are made with a type of viscoelastic polyurethane foam that is famous for its exceptional ability to mold itself to other shapes, while allowing for a complete return to its original form after use. Depending on the composition of the foam, the speed of recovery can be controlled, a property that is used to great effect in the “Mute Room” auditorium, designed by Thom Faulders for the California College of the Arts in San Francisco, California. Besides providing excellent sound absorption, the gently curved foam flooring also adds a visual dimension, as it slowly recovers when you move across the surface. The manufacturer of the foam, FoamPartner, has recently developed a new process called StructUre, which makes it possible to cost-effectively produce selectively hardened foam parts, further enhancing the tactile qualities of this amazing material.

But polyurethane has many other remarkable properties besides elasticity. For example, the chemical structure of the material can be modified so that it absorbs liquids, a feature that has found a major application in the next generation of medical wound dressings, but there are other creative uses for this material.

Perhaps best described as a kind of three-dimensional copy machine with an enlargement function, Hydrospan makes it possible to scale up an object by about 60 percent. The process involves making a mold from an existing object, casting it with Hydrospan and then soaking the material in water until it is fully expanded before using the enlarged model to make the final mold.

Manufactured by Industrial Polymers, Hydrospan is currently mainly used by model makers to enlarge small objects, but it would be interesting to see how this material would translate into more consumer-led products.

Perhaps you’ve seen a demonstration of polyurethane ingredients being mixed together, causing a very rapid and almost violent foaming reaction. Reaction injection molding exploits this property and the expanding insulation foam that you can pick up at your local hardware store works on the same principle.

Using the foaming reaction as a design feature in itself is not nearly as common, however. Francois Azambourg’s “Pack” chair is a great example. Designed with the intention of selling it via mail order, the chair is fabricated with an internal airtight polyester cloth pouch and a double lining that contains a two-part liquid polyurethane foam. Activating a switch on the side of the flat chair, the user can start the release of the material, causing it to combust and fill the inside. Within a few seconds the form is rigid.

More information: Bayer MaterialScience AG is a major manufacturer of polyurethanes, and so is Dow Chemical Co. Both have extensive ranges of different grades and additives. Technogel Italia S.R.L. is the maker of the iconic gel material and FoamPartner Fritz Nauer AG is a large manufacturer of polyurethane foams.

Key features

• New varieties are being developed all the time, so it’s definitely worth keeping up with polyurethane-related news.
  
• There are droves of compatible additives, from colours and special effects to all kinds of performance-enhancing properties
  
• Good chemical resistance and the material is considered hypoallergenic
  
• Depending on the form of polyurethane, the material has good strength and dimensional stability, as well as shape recovery and elasticity
  

Typical applications

Furniture, upholstery, electronics, automotive parts, surfboards and skateboard wheels, large kitchen appliances, medical equipment, textiles, coatings, adhesives and fillers. If that’s not enough, look a little further and you’ll find that polyurethane is also used in such exotic areas as the production of metal and ceramic foams, the fake glass that used in Hollywood, moisture-absorbent wound dressings and self-healing ballistic armor.

Chris Lefteri, product designer and principal of Chris Lefteri Design Ltd. in Barnet, England, is internationally recognized as an authority on materials and their application in design, with eight books on the subject to his credit. Lefteri can be reached through his Web site at ChrisLefteri.com/.