聚氨酯硬段堆叠结构的再发现：类结晶行为

利用傅里叶变换红外技术（FT-IR）首先阐明了本文工作中的聚氨酯氢键缔合程度或微相分离程度与热历史无关，只与样品所处温度有关。其次，利用差示扫描量热法（DSC）探究了升降温过程中出现的热效应，发现热效应所对应的硬段缔合结构与聚合物结晶行为非常相似，例如有缔合核存在下的快速生长、硬段较多时的快速生长、等温退火后生成特定的缔合结构等。综合以上实验结果可以发现，这些缔合结构的行为非常类似于高分子晶体。但与传统观点不同的是，微相分离与这些潜在的类结晶行为是两个独立的过程。

Rediscovery of the associated structure of polyurethane hard segments: crystallization-like behavior

Hydrogen bond association, microphase separation, and crystallization in polyurethane have not previously been clearly distinguished and explained. This work uses FT-IR spectroscopy to confirm that the degree of hydrogen bonding in polyurethane and the degree of microphase separation are independent of the thermal history and only related to the temperature at which the sample was treated. Using the DSC method, the thermal effects appearing during the heating and cooling process were then explored. It was found that the hard segment associated structure corresponding to the thermal effect is very similar to the crystallization behavior of the polymer, as shown, for example, by the rapid growth in the number of associated cores, the rapid growth in the number of hard segments, and the formation of a specific associated structure after isothermal annealing. Combining these experimental results shows that the behavior of these associated structures is very similar to polymer crystals, and that microphase separation and potential crystallization are two separate processes.