Microphase separation and hard segment packing in polyurethanes remain areas of active research interest in order to optimize their performances. In this work, a commercial thermoplastic polyetherurethane (1180A, BASF) is used as a model system to investigate the packing of hard segments during microphase separation. Although DSC studies show several transitions during heating and cooling, no crystal structure is detected by XRD. Nevertheless, these endothermic and exothermic peaks should belong to the complicate hard/soft segment interaction and related structures. Time and temperature dependent FTIR spectra prove fast hydrogen bonding association/dissociation phenomena in the current system. We infer that such fast process can induce loosely or irregular packing of hard segments during cooling. On the other hand, the continuous change of degree of microphase separation with temperature implies different hard domain structures and stabilities at different temperatures. At high temperature, only hard domains with large size and compactly packed segments can survive. This is because the thermodynamic stability of hard domains is decided by the strength of hydrogen bonding and the size of hard domain, similar with classical description of ‘nucleation’. Morphological information obtained by fitting the SAXS curves proves the validity of the above model. Moreover, the significant difference in mechanical properties before and after thermal treatment can be explained by the microstructure model.

为了优化其性能，聚氨酯中的微相分离和硬链段填料仍然是活跃的研究兴趣领域。在这项工作中，将商用热塑性聚醚氨酯（1180A，BASF）用作模型系统，以研究微相分离过程中硬链段的堆积。尽管DSC研究表明在加热和冷却过程中发生了几次转变，但是XRD并未检测到晶体结构。然而，这些吸热和放热峰应该属于复杂的硬/软链段相互作用和相关结构。时间和温度相关的FTIR光谱证明了当前系统中快速的氢键缔合/解离现象。我们推断，这种快速过程会导致冷却过程中硬段的松散或不规则堆积。另一方面，微相分离度随温度的连续变化意味着不同的硬畴结构和在不同温度下的稳定性。在高温下，只有大尺寸的硬区域和紧密堆积的链段才能幸存。这是因为硬结构域的热力学稳定性取决于氢键的强度和硬结构域的大小，与“成核”的经典描述相似。通过拟合SAXS曲线获得的形态学信息证明了上述模型的有效性。此外，可以通过微观结构模型解释热处理前后的机械性能的显着差异。只有具有大尺寸和紧凑压缩段的硬域才能生存。这是因为硬结构域的热力学稳定性取决于氢键的强度和硬结构域的大小，与“成核”的经典描述相似。通过拟合SAXS曲线获得的形态学信息证明了上述模型的有效性。此外，可以通过微观结构模型解释热处理前后的机械性能的显着差异。只有具有大尺寸和紧凑压缩段的硬域才能生存。这是因为硬结构域的热力学稳定性取决于氢键的强度和硬结构域的大小，与“成核”的经典描述相似。通过拟合SAXS曲线获得的形态学信息证明了上述模型的有效性。此外，可以通过微观结构模型解释热处理前后的机械性能的显着差异。