Paez-Amieva Yuliet, Martín-Martínez José Miguel
Adhesion and Adhesives Laboratory, University of Alicante, 03080 Alicante, Spain.
Polymers (Basel). 2024 Sep 26;16(19):2724. doi: 10.3390/polym16192724.
Different polyurethanes (PUs) were synthesized with polycarbonate polyols of molecular weights of 500, 1000, and 2000 Da. Their self-healing abilities at 20 °C were tested, and their structural, thermal, and mechanical properties were analyzed. The PUs made with polycarbonates of molecular weights 500 (YC500) and 1000 Da (YC1000) exhibited self-healing at 20 °C, and the self-healing time of YC1000 was the shortest. The absence of crystallinity and the low degree of micro-phase separation favored self-healing at 20 °C in YC500. However, the presence of tack and the existence of allophanate species and urethane-carbonate and urea-carbonate hydrogen bonds disfavored self-healing. Consequently, the self-healing time at 20 °C of YC500 was longer than expected. On the other hand, YC1000 exhibited an "equilibrium" between urethane-carbonate and urea-carbonate hydrogen bonds and carbonate-carbonate interactions among the soft segments, so a particular structural order was produced that was associated with its fastest self-healing at 20 °C. The PU made with the polycarbonate of molecular weight 2000 Da did not exhibit self-healing at 20 °C because of its significant micro-phase separation, the presence of semi-crystalline soft domains, and the lower density of hydrogen bonds.
用分子量为500、1000和2000道尔顿的聚碳酸酯多元醇合成了不同的聚氨酯（PU）。测试了它们在20℃时的自愈能力，并分析了它们的结构、热性能和力学性能。由分子量为500（YC500）和1000道尔顿（YC1000）的聚碳酸酯制成的聚氨酯在20℃时表现出自愈能力，且YC1000的自愈时间最短。YC500中不存在结晶性且微相分离程度低有利于其在20℃时自愈。然而，粘性的存在以及脲基甲酸酯物种、聚氨酯-碳酸酯和脲-碳酸酯氢键的存在不利于自愈。因此，YC500在20℃时的自愈时间比预期的要长。另一方面，YC1000在聚氨酯-碳酸酯和脲-碳酸酯氢键与软段中的碳酸酯-碳酸酯相互作用之间表现出一种“平衡”，因此产生了一种特定的结构有序性，这与其在20℃时最快的自愈相关。由分子量为2000道尔顿的聚碳酸酯制成的聚氨酯在20℃时未表现出自愈能力，因为其显著的微相分离、半结晶软段的存在以及氢键密度较低。
