Foam rubber (also known as cellular, sponge, or expanded rubber) refers to rubber that has been manufactured with a foaming agent to create an air-filled matrix structure.
Commercial foam rubbers are generally made of either polyurethane or natural latex. Latex foam rubber, used in mattresses, is well known for its endurance. Polyurethane is a thermosetting polymer that comes from combination of Methyl di-isocyanate and polyethylene and some other chemical additives.
Wikipedia contributors. (2018, January 25). Foam rubber. In Wikipedia, The Free Encyclopedia. Retrieved 11:16, March 19, 2018, from https://en.wikipedia.org/w/index.php?title=Foam_rubber&oldid=822290428