Aging of polyurethane foams

Abstract The degradation of foam thermal properties due to the diffusion of the air into the foam, termed the foam aging, is a major drawback of polyurethane foams. An analytical model was developed to predict the effective diffusion coefficient of the foam and from it the rate of gas diffusion and foam aging. The model requires a measurement of the wall permeability and foam internal geometry. An experimental steady-state technique was developed to measure the permeability of the cell walls. To check the models an experimental technique was developed to measure the foam effective diffusion coefficient. The model predictions of the effective diffusion coefficient were found to be within 29% of the foam data or better.