Solar Energy, Vol.194, 893-902, 2019
Study on rheological properties and phase-change temperature control of asphalt modified by polyurethane solid-solid phase change material
Polyurethane solid-solid phase change material (PCM) with low phase change temperature is synthesized via prepolymer method. The synthetic polyurethane solid-solid PCM had lower crystallinity than PTMEG2000. The polyurethane solid-solid PCM was still in solid state during the heating process, and no liquid leakage was observed. After many phase change cycles, the polyurethane solid-solid PCM exhibited good stability of phase change cycles. Hence, the asphalt modified by polyurethane solid-solid PCM was prepared by high-speed shearing method. With increasing polyurethane solid-solid PCM proportion, the high temperature deformation resistance of modified asphalt gradually increased. At low temperature (< - 18 degrees C), the addition of the polyurethane solid-solid PCM improved the low temperature performance of asphalt. With increasing polyurethane solid-solid PCM proportion, the specific heat capacity of the modified asphalt gradually increased. When the polyurethane solid-solid PCM proportion was > 3 wt%, the specific heat capacity of the modified asphalt had an evident peak ranging from 13 degrees C to 25 degrees C. In the range of the proportion, the coefficient of the heat conductivity of the modified asphalt gradually increased with increasing PCM content. During the cooling process, the modified asphalt cooled relatively slow before the phase transition of the polyurethane solid-solid PCM. With continued decrease in the temperature, the phase transition of the polyurethane solid-solid PCM occurred, and the cooling rate of the modified asphalt further decreased. With increasing polyurethane solid-solid PCM content, the temperature control ability of modified asphalt and the efficiency of temperature control gradually increased.