One of the most common and beloved packing materials now comes in a metal form.
Bubble Wrap®—first invented as three-dimensional wallpaper, believe it or not—started protecting valuables in 1960 and is branded by the Sealed Air company. It's typically made from polyethylene, where a bubble-shaped side is bonded to a flat side.
The new metallic form can offer protection in very, very tight spaces, only a few millimeters thick. So packaging can be made very, very small and much stronger than the plastic variety. Computer and cell phone cases could be made much more thin and sleek. Computer parts could be protected with very little space used. Even helmets would not need to be as bulky. The protection offered is more heat and chemical resistant and more flexible than any other bubble wrap.
Making the metallic wrap is surprisingly simple. Afsaneh Rabiei, professor of engineering North Carolina State University, and her team started with a thin sheet of aluminum and used a studded roller to form small indents in the sheet. Instead of capturing air in these indentations, she filled them with a foaming agent like calcium carbonate or titanium hydrate. When such agents are heated they form bubbles within the metal, as you can see here:
Then they bond this "indented" sheet to another flat sheet of aluminum essentially sandwiching the foaming agent in the separate recesses. Last, they heat the bonded sheets and the foaming agent forms bubbles, much in the way baking soda causes a cake to form its porous crumb. It is the bubbles that absorb the energy and shock from any load placed on the material.
This new material weighs 20 to 30 percent less than regular sheet metal, yet there is nearly a 50 increase in strength. Apparently this method can be used with any sheet metal—not just aluminum.
Other uses can include structural parts in cars or airplanes, and anything that requires protection or packaging during transport. Rabiei says she has not thought of all possible uses yet, but says the commercial prospects for such material is promising. The cost is comparable to regular sheet metal, since this new bubble wrap requires no extensive equipment or environment for processing—any of the rolling or heating can be accomplished in any sheet metal shop.
One surefire application we can think of: Rolls of the stuff could be given to that Atlas robot to play with, since he's probably stressed out that he can't get into cars well.
For more on aluminum foam, click here.
For more on bubble wrap and "Bubble Wrap® Appreciation Day," click here.