... more of the gas phase is present, the foam becomes softer. Wang4 reported that the higher energy absorption of the lower relative density foams is a result of the larger deformation, the bending ... volume and the average cell size. An increase in the blowing agent concentration resulted in smaller, finer, and more uniform cells. The decomposition of high concentrations of carbon dioxide ... packaging, thermal and acoustic insulator properties, moderate energy absorption, and low cost.1–5 The containment of the gas phase within the polymeric cell walls provides excellent properties...