Mechanophores in self-healing polymers: Influence of mechanical bond activation on the self-healing performance of polymers

自修复聚合物中的力力团：机械键活化对聚合物自修复性能的影响

• 批准号: 398304946
• 负责人: Dr. Martin Hager
• 金额: --
• 依托单位: Institut für Organische Chemie und Makromolekulare Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/398304946?language=en
• 关键词: Mechanophores; self; healing; polymers; Influence

Self-healing polymers are capable of restoring their original functionalities after being damaged. In particular, intrinsic self-healing polymers based on different reversible interactions have been investigated intensively. Besides different supramolecular interactions mainly reversible covalent interactions have been studied. Within this context reversible addition (e.g. Diels Alder reaction) as well as condensation reactions (e.g. imines, acylhydrazones) have been investigated. Much research was devoted to elucidate the healing process and the underlying healing mechanism, respectively, of different reversible polymer networks. Despite the significant knowledge gained, the damage event as well as the results of the damage (besides an obvious scratch/crack) remain uncertain. Consequently the question arises: 'Are the reversible covalent bonds really predetermined breaking points?'Within this context this project aims at the elucidation of the occurring processes in reversibly crosslinked polymers by the introduction of mechanophores. These mechanophores will be based on donor-acceptor systems, which will be incorporated into reversible covalent bonds (thiol-ene reaction, Diels Alder cycloaddition, imines). The nature of the reversible bond (open or closed) will result in a shift of the UV vis absorption allowing the monitoring of this bonds. By this manner first the damage process can be investigated, subsequently, the healing of this polymer networks can be monitored. Consequently, the nature of the damage in connection with the mechanical activation of the polymer, i.e. of the reversible bonds, will be investigated. Different damage scenarios might lead to different activation patterns within the polymer network and consequently in differences in the healing. Noteworthy, this mechanophores will also allow a detailed study of imines, which will show a healing process based on exchange reactions. Most molecular characterization techniques will not reveal much details in case of exchange reactions (in comparison to a full opening of the reversible binding units).

自修复聚合物能够在受损后恢复其原始功能。特别是，基于不同可逆相互作用的本征自修复聚合物已被深入研究。除了不同的超分子相互作用，主要是可逆的共价相互作用已被研究。在此背景下，可逆加成（例如Diels桤木反应）以及缩合反应（例如亚胺，酰腙）已被研究。许多研究致力于阐明愈合过程和愈合机制，分别不同的可逆聚合物网络。尽管获得了重要的知识，但损坏事件以及损坏结果（除了明显的划痕/裂纹）仍然不确定。 因此，问题就来了：可逆共价键真的预先决定了断裂点吗？在此背景下，该项目旨在通过引入机械载体来阐明可逆交联聚合物中发生的过程。这些机械载体将基于供体-受体系统，其将并入可逆共价键（硫醇-烯反应、Diels桤木环加成、亚胺）。可逆键的性质（开放或闭合）将导致UV维斯吸收的偏移，从而允许监测该键。通过这种方式，首先可以研究损伤过程，随后，可以监测这种聚合物网络的愈合。因此，将研究与聚合物的机械活化有关的损伤的性质，即可逆键的性质。不同的损伤情况可能导致聚合物网络内不同的激活模式，从而导致愈合的差异。值得注意的是，这种机械载体也将允许详细研究亚胺，这将显示基于交换反应的愈合过程。在交换反应的情况下，大多数分子表征技术不会揭示太多细节（与可逆结合单元的完全打开相比）。