Wang Shanshan, Song Jiayao, Chen Keping, Henderson Mark Julian, Tian Qiang, Almásy László
State Key Laboratory of Environment-Friendly Energy Materials, School of Materials and Chemistry Southwest University of Science and Technology Mianyang621010 People's Republic of China.
Institute of Chemical Materials China Academy of Engineering Physics Mianyang621900 People's Republic of China.
J Appl Crystallogr. 2025 Mar 19;58(Pt 2):564-572. doi: 10.1107/S1600576725001633. eCollection 2025 Apr 1.
This study investigated the effects of solvent vapor annealing on the microphase separation structure of polyurethane (PU) using small-angle X-ray scattering (SAXS) and complementary techniques. Solvent annealing, as an alternative to thermal annealing, offers a lower-temperature method to refine the microstructure of PU. We examined the impact of methyl ethyl ketone (MEK), acetone and toluene vapors on a commercial polyether PU, focusing on changes in microphase structure, adsorption kinetics and thermal stability. The SAXS data, analyzed by a polydisperse hard-sphere model, indicated that the degree of phase separation increased upon solvent annealing, and the order of influence exerted by the solvent vapors on the microphase structure follows MEK > acetone > toluene. The variable-temperature SAXS results showed that the solvent-annealed sample had superior thermal stability to the quenched sample. Compared with high-temperature annealing, solvent annealing induced a higher degree of phase separation but did not lead to significant growth of the hard-urethane-segment-rich domains. These findings provide valuable insights into optimizing solvent annealing processes, allowing for advanced applications of PUs where excessive heat may lead to degradation or other undesirable changes.
本研究采用小角X射线散射（SAXS）及其他相关技术，研究了溶剂蒸汽退火对聚氨酯（PU）微相分离结构的影响。作为热退火的替代方法，溶剂退火提供了一种低温方法来细化PU的微观结构。我们研究了甲乙酮（MEK）、丙酮和甲苯蒸汽对一种商用聚醚PU的影响，重点关注微相结构、吸附动力学和热稳定性的变化。通过多分散硬球模型分析的SAXS数据表明，溶剂退火后相分离程度增加，且溶剂蒸汽对微相结构的影响顺序为MEK>丙酮>甲苯。变温SAXS结果表明，溶剂退火样品比淬火样品具有更好的热稳定性。与高温退火相比，溶剂退火诱导了更高程度的相分离，但并未导致富含硬聚氨酯链段的区域显著生长。这些发现为优化溶剂退火工艺提供了有价值的见解，有助于PU在高温可能导致降解或其他不良变化的先进应用中发挥作用。
