| Summary: | 碩士 === 中國文化大學 === 化學工程與材料工程學系奈米材料碩士班 === 105 === In this paper, research the foaming behavior of thermoplastic polyurethane (TPU) using supercritical carbon dioxide (scCO2), change the operating conditions, explore the change of pore structure, and analysis of cell pore size data.The foaming temperature is 140 ℃ to 160 ℃,the foaming pressure is3000, 3750, 4500 psi the pressure relief method considers the combination of the speed and the segmentation. At different foaming temperature, foaming pressure and pressure relief mode of the combination, resulting in a great difference in the results of the foam. and use the scanning electron microscope (SEM) to observe the cell morphology at various operating conditions. The results reveal that when the foaming temperature, the foaming pressure, and the saturation time all increase, but the depressurization rate is low, the cell average size (Davg) becomes larger but the cell density (Nf) becomes lower. A pressure relief of the cells are more uniform, Segmental pressure relief of the cells are more uneven, The way and the amount of pressure relief will also affect the size of the cell; 160 ℃, 3000psi, saturated 120min, the first rapid pressure relief to 0psi, and then plus back to 3000psi and re-saturated 30min finally rapid pressure to 0psi to achieve the maximum cell conditions.
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