Shape Memory Polyurethane Foam for Thermal Insulation

Abstract

Foam materials are widely used as insulators, because they have a structure stability as well as a low thermal conductivity. In order to manufacture an efficient insulation material, shape memory polyurethane (SMPU) foam was prepared and its thermal conductivity was measured. The relation between thermal conductivity and microstructure of the foam was studied. The experimental thermal conductivities of the SMPU foam specimens were compared to theoretical thermal conductivities of those. SMPU was synthesized by using prepolymerization method. Differential Scanning Calorimeter (DSC) was used to examine the transition temperature (T_tr) of SMPU. SMPU foams were obtained by the salt leaching method and prepared with respect to particle size of salts in order to control the pore size of the SMPU foam. Hybrid foam was fabricated by mixing two different sizes of NaCl particles and functionally gradient foam was also manufactured by laminating layers of three different sizes of NaCl particles. The thermal conductivity, mechanical property, shape memory properties were characterized and thermal resistance of various specimens were also calculated to investigate adiabatic properties. SMPU foam has advantages of space occupancy and wearability because it can be fixed to thin shape at room temperature. When SMPU foam recovers to its original thickness at above T_tr, the thermal resistance is increased. SMPU foam is expected to be used in insulation field as an intelligent adiabatic material.