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 a warm body in a few minutes. Newer foams may recover more quickly to their original shape.