Abstract Traditional hot melt adhesives are thermoplastic resins with non-covalent hydrogen bonds. In this letter, a polyurethane hot melt adhesive (CDI-PUR-DA) was synthesized via introducing thermally reversible covalent Diels-Alder adducts into the polyurethane main chain. Results from hydrogen nuclear magnetic resonance (NMR) analysis and an assessment of rheological properties demonstrated that CDI-PUR-DA exhibited a much lower viscosity than a traditional hot melt adhesive. The viscosity of the polyurethane decreased to 4 Pa s at 110 °C due to rupture of Diels-Alder adducts. However, the viscosity returned to its initial value on cooling due to the regeneration of the Diels-Alder adducts. This approach provides a new method for preparing hot melt adhesives.

中文翻译：

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基于狄尔斯-阿尔德反应的聚氨酯热熔胶

摘要 传统的热熔胶是具有非共价氢键的热塑性树脂。在这封信中，通过将热可逆共价狄尔斯-阿尔德加合物引入聚氨酯主链，合成了聚氨酯热熔胶 (CDI-PUR-DA)。氢核磁共振 (NMR) 分析和流变特性评估的结果表明，CDI-PUR-DA 的粘度比传统热熔胶低得多。由于狄尔斯-阿尔德加合物的破裂，聚氨酯的粘度在 110 °C 时降至 4 Pa s。然而，由于狄尔斯-阿尔德加合物的再生，粘度在冷却时恢复到其初始值。该方法为制备热熔胶提供了一种新方法。