The Fatigue of Flexible Urethane Foam

Abstract

The static fatigue technique is the simplest effective test of loss of load bearing capacity with use. Good correlation between results of the static technique and in-use tests on poly ether slab mattresses and molded topper pads demonstrates that in-use performance can be predicted by its use. The mechanism of fatigue appears to in volve hydrogen bond rearrangement under stress with a return to the original alignment upon removal of the stress. The objective of minimizing realignment, and thereby mini mizing fatigue, may be accomplished by re ducing water content in the foam formulation and increasing the isocyanate index.