Negative Poisson's ratio foam as seat cushion material

Negative Poisson's ratio foam was used in the development of seat cushions which exert reduced peak pressure upon the skin of seated persons. Foam processing techniques were scaled up. A longer processing time was required for cushion size samples in comparison with small samples. Pressure distributions on a seated subject were measured using a pressure-sensitive array. Seated pressure distribution became more favourable with decreasing sample density for both conventional and re-entrant foam blocks. Foam thickness played a small role in the seated pressure performance of foam cushions. Re-entrant foam at densities of between 2 and 4 lb/ft(3) (0.032 to 0.064 g/cm(3)) performed better (lower maximum seating pressure) than conventional foam samples of comparable density.