What are the advantages and disadvantages of polyurethane foam?

Answer 1

There are two kinds of polyurethane (PUR) foam - rigid and flexible. Rigid foam is used to make hard products like surfboards. Flexible foam is used as padding.

Rigid foam has a lot going for it: It is relatively lightweight. It is strong. It makes a good thermal insulator. A foam-plastic composite can be made with fiberglass and polyester resin rather than cloth and epoxy. (Epoxy is much more dangerous to handle than polyester, and it's far more expensive.)

Flexible foam is also a good product: Because of the way it is made - you stir two liquid chemicals and a "blowing agent," which makes it foam up, together and pour it into a mold - you can create all sorts of custom shapes. It's hypoallergenic, which foam rubber is not. It's less expensive than real foam rubber. And you can alter the firmness of the finished foam by choosing the components properly.

Disadvantages? The two chemicals it's made from are hazardous. Many, but not all, PUR foams are flammable. If you do manage to set this stuff on fire, here's what happens.

The combustion temperature of PUR foam is about 2000 degrees Fahrenheit, and it burns so fiercely fire departments call PUR foam "solid gasoline." I have seen a PUR fire in person. They aren't kidding.

The two main components of PUR smoke are carbon monoxide and hydrogen cyanide. Both are lethal gases.

If you are in a PUR fire, one of three things is going to happen to you: You could roast to death. If the heat doesn't kill you, the toxic gases will kill you. If you survive both of those, you can look forward to quivering muscles, venous blood that looks like arterial blood, and weird liver enzyme test results for the rest of your days because hydrogen cyanide affects the central nervous system, the bloodstream and the liver.