What is memory foam?

Visco elastic memory foam is a material that is present in a large number of orthopedic beds and mattresses and its popularity and market presence is still on the increase.

Visco elastic memory foam has as its base a polyurethane, but its unusual properties are the result of the addition of some other compounds which increase its density (hence it weight) and confer the slow recover characteristic for which it is famous.

It was originally called “slow spring back foam”, a reference to its very different way of recovering from the application of pressure.

The high density memory type foam has a number of properties that make it valuable as a mattress filling material. Firstly, the density makes it less compressible than a lighter foam and this makes it more able to contour itself and offer resistance to a heavy weight like a human body.

Secondly, it is also reactive to heat and this means that, after initially shaping around the mass placed on it, it further moulds as it absorbs the heat from that mass, i.e. a persons body heat. For this reason memory foam is described as being temperature sensitive.

How memory foam was developed

Memory foam first emerged in the late 1960's. It was developed as a NASA initiative that focussed around looking at new materials and products. Memory foam was initially the result of a product development program that looked at ways of improving the cushioning properties of the seats used in planes, possibly rockets and the shuttle program etc.

Although memory foam appears to have excellent supportive characteristics, its high density and weight mean that its use in these areas will have been limited and possibly non existent. (There are no publicly available records of memory foam being used in the Space Program.)

Over the next decade and a half different uses for memory foam were explored before, in the 1980’s, a company began to look at using this unique foam in beds.

Ultimately, the first mattresses to use what we now know as visco elastic memory foam were produced by a company called Fagerdala and they created the company Tempur who produce the Tempur Pedic memory foam mattress. These mattresses first appeared on public sale in the early 1980's.

Initially, memory foam mattresses were very expensive and their use was limited to the medical sector where they were seen as being beneficial to those suffering from specific sensitivity like bed sores. As time has gone by and sales have increased and production techniques have been rationalised, prices have become more affordable. Even so, memory foam mattresses are still more expensive than many spring based mattresses, however their connection with the medical profession and the orthopedic sector have given them a perceived superiority over other mattress types.

Some negatives to memory foam

Despite its popularity as a bedding material, memory foam does have a couple of negative features associated with it.

The first is the engulfing, almost swallowing-you-up feel that the material has when used in a mattress. Many people find this highly desirable, but a few (and I am one) do not. This property will also be a problem for anyone (including very young children) who find moving challenging as it takes more effort to move one’s position in a memory foam bed than on a spring based bed. There is a slight quick sand effect as one tries to move out of the mattress’s depression and the memory foam immediately shapes itself to the new, adjusted, position of the person trying to move.

The second is an odour that some (not all) memory foam mattresses release when they are first used. This can last anything from a few days to a few weeks. It tends to be more common with the cheaper foams, however this is not always the case. Some people can be sensitive to this odour.