Li Chuanlong, Dong Wenbo, Li Longyu, Dou Zhengli, Li Yuhan, Wei Liuhe, Zhang Qin, Fu Qiang, Wu Kai
College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, P. R. China.
College of Chemistry and Green Catalysis Center, Zhengzhou Key Laboratory of Elastic Sealing Materials, Zhengzhou University, Zhengzhou 450001, P. R. China.
Mater Horiz. 2023 Oct 2;10(10):4183-4191. doi: 10.1039/d3mh00966a.
Strong and ductile adhesives often undergo both interfacial and cohesive failure during the debonding process. Herein, we report a rare self-reinforcing polyurethane adhesive that shows the different phenomenon of only interfacial failure yet still exhibiting superior adhesive strength and toughness. It is synthesized by designing a hanging adhesive moiety, hierarchical H-bond moieties, and a crystallizable soft segment into one macromolecular polyurethane. The former hanging adhesive moiety allows the hot-melt adhesive to effectively associate with the target substrate, providing sufficient adhesion energy; the latter hierarchical H-bond moieties and a crystallizable soft segment cooperate to enable the adhesive to undergo large lap-shear deformations through sacrificing weak bonds and mechano-responsive strength through the fundamental mechanism of strain-induced crystallization. As a result, this polyurethane adhesive can keep itself intact during the debonding process while still withstanding a high lap-shear strength and dissipating tremendous stress energy. Its adhesive strength and work of debonding are as high as 11.37 MPa and 10.32 kN m, respectively, outperforming most reported tough adhesives. This self-reinforcing adhesive is regarded as a new member of the family of strong and ductile adhesives, which will provide innovative chemical and structural inspirations for future conveniently detachable yet high-performance adhesives.
强韧性粘合剂在脱粘过程中通常会发生界面和内聚破坏。在此，我们报道了一种罕见的自增强聚氨酯粘合剂，它呈现出仅界面破坏的不同现象，但仍具有优异的粘合强度和韧性。它是通过将悬挂式粘合部分、分级氢键部分和可结晶软段设计到一个大分子聚氨酯中合成的。前者悬挂式粘合部分使热熔粘合剂能够与目标基材有效结合，提供足够的粘合能；后者分级氢键部分和可结晶软段协同作用，使粘合剂通过牺牲弱键来承受大的搭接剪切变形，并通过应变诱导结晶的基本机制实现机械响应强度。结果，这种聚氨酯粘合剂在脱粘过程中能保持自身完整，同时仍能承受高搭接剪切强度并耗散巨大的应力能。其粘合强度和脱粘功分别高达11.37 MPa和10.32 kN m，优于大多数已报道的韧性粘合剂。这种自增强粘合剂被视为强韧性粘合剂家族的新成员，将为未来方便拆卸但高性能的粘合剂提供创新的化学和结构灵感。
