Cryogenic characterisation of polyurethane foam for thermal insulation of cryogenic tanks of launch vehicles

PUR foam was characterized for density, thermal conductivity, compressive and tensile strength. Among these properties, compressive and tensile strength were evaluated at 300 K, 77 K and 20 K. Results indicated that density of PUR foam in the range of 31 to 35 kg/m³ with a compressive strength of 2.0 to 2.5 ksc was obtained. Thermal conductivity of PUR foam was in the lower range of 0.030 to 0.035 W/mK, making it suitable choice for thermal insulation. Thermal stability was analysed using thermogravimetric analysis and the PUR foam was stable up to 220 °C. Specific heat of PUR foam was obtained in the range of 1200 – 1400 J/kgK. Low temperature characterization indicated that compressive strength is ranging from 5.0 to 8.0 ksc. This effect may be due to the higher stiffness of PUR foams at cryogenic temperatures, making it suitable for thermal insulation of cryogenic tanks in launch vehicle applications.