In the 1930s, the primary goal of the establishment of urethane science was to produce fibers to replicate the success of nylon (polyamide). During the Second World War, Germany I G. Farbenindustrie has developed a lightweight, high-strength, rigid PU foam and moisturizing material for use in aircraft components and ships and tanks. Later, people found that the performance of some other parts was not perfect. Technical improvements are also needed. After nearly 80 years of development of foam plastics, it was thought that performance and application were necessary tests for technological development. It then determines the target market, because the success of the market will no doubt reward scientific and technological research. In order to fully understand the properties of foam, it must be started from the foundation. Compared with inorganic materials, polymers have an interesting organic long-chain structure and exhibit unique properties. Like foamed inorganic materials, foamed organic materials also expand the range of polymer materials. Its morphology and structure are the main determinants of foam performance.

It is well known that most thermodynamic properties are based on mass, such as heat capacity, heat enthalpy, and latent heat. In addition, most of the properties remain unchanged because the quality of the gas is almost negligible. However, volume-based performance and structure-related performance are quite different.