What is Memory Foam?
Memory foam is soft open-cell polyurethane foam with viscoelastic properties. When compressed, it is both viscous and elastic, deforming gradually, and recovering just as gradually when released. Memory foam holds its shape temporarily; that is to say that a hand pressed into a sheet of foam will leave a clear impression for a few seconds. In essence, the foam “remembers” the hand imprint for a short period of time before returning to its original shape. Memory foam is generally used to relieve pressure points by gradually distributing that pressure over a greater surface area.
Memory foam was initially developed under a NASA contract in 1966. Contrary to popular belief, it was not developed for astronauts, but rather for the comfort of airplane test pilots. Memory foam was originally known as “temper” or “slow spring back” foam. Originally, it was expensive to produce and was, in some cases, made with harsh chemicals. Furthermore, “temper” foam was initially extremely sensitive to temperature; very soft when warm, and very hard when cold.
Since 1966, the formulation of memory foam has been improved to be less temperature sensitive, and much more environmentally friendly. NASA released the foam to the public domain in the early 1980s. Since then, it has been used in office chairs, pillows, mattresses, couches, shoes, helmets, and a huge variety of other products.
Memory foam is primarily used in medical devices. Applications include specialized beds and chairs to reduce incidence of pressure sores, prosthetics, splints, and body supports. Generally, memory foam is used in medical applications where distribution of weight or pressure is important.
Today’s primary consumer application of memory foam is in mattresses. Since their introduction in the mid 1990s, memory foam mattresses have been generally recognized as the most comfortable, durable, and safe mattresses available. A memory foam mattress automatically adjusts its shape to match the contour of any object. Similar to its application in the medical field, memory foam mattresses naturally distribute weight evenly across the whole surface area of a sleeping person, eliminating pressure in any one particular spot.
Probably the most interesting application of memory foam is its use in the recovery of gravity-deprived astronauts. Astronauts returning from space experience difficulty with balance and walking as they re-adapt to gravity on Earth. The floor of both NASA’s and the Russian Space Agency’s gravity re-training gyms are covered with a 4-inch thick layer of memory foam. The special floor provides an unstable support surface that increases the challenge for astronauts regaining their equilibrium.