Thermal and mechanical analysis of polyurethane memory foam

Some mattresses and pillows manufactured recently exhibit the unusual properties of viscoelastic slabstock foam, marketed as memory foam. These properties include a delayed and damped response to an applied force, and the ability to both absorb energy and to flow to minimize stresses. Many other polymeric materials display similarly complex viscoelastic properties at elevated temperatures at which compression properties may be a problem for processing. Analyzing this material offers a chance to use dynamic mechanical analysis (DMA) to characterize a material whose room temperature viscoelastic properties are unusual, and yet familiar.