My First Crib Mattress, Memory Foam Crib Mattress, Removable Waterproof Cover, Plush, Hypoallergenic Have you made up your mind that you are getting a quality memory foam mattress? Congratulations, this is a wise choice as you are choosing one of the most popular and comfortable materials when it comes to mattresses that help you sleep like a baby. Heres a new one for you all. I bought a spa sensation memory foam mattress from on-site through Walmart. Now the mattress is two pieces with a mesh cover over the two mattresses I have had the mattress a little over a year now I’m very meticulous about making sure my bed stays clean and that I am comfortable so I can sleep because I have leukemia. Memory foam consists mainly of polyurethane as well as additional chemicals increasing its viscosity and density.It is often referred to as “viscoelastic” polyurethane foam, or low-resilience polyurethane foam ().The foam bubbles or ‘cells’ are open, effectively creating a matrix through which air can move. Higher-density memory foam softens in reaction to body heat, allowing it to mold to .