Malleability of highly cross-linked polymers – an investigation of the topology freezing phenomenon of Vitrimers via static and dynamic means and its relevance for the solution of technological challenges

玻璃化聚合物是一种新型聚合物，它结合了热塑性塑料的延展性和高度交联型热固性塑料的非凡机械性能。玻璃化聚合物的巨大优势在于，即使它们是交联的，即它们的分子状态远远超过结构渗流阈值，它们也可以被修复、重塑甚至回收。这是因为存在可切换的分子键。因此，玻璃化聚合物不仅是可持续的，而且能够为加工技术提供新的视角，例如通过重复成型工艺，以及提高聚合物应用在使用中的寿命和耐久性的机会。然而，从工程学的角度来看，目前利用玻璃体的令人兴奋的性质缺乏对潜在的物理和物理化学机制的了解。对于基于玻璃体的复合材料来说，这一点更加重要，因为当额外的物理和化学作用开始发挥作用时，例如纤维和玻璃体基质之间的作用。在这项研究提案中，沃尔特·本杰明项目的早期博士后和申请者旨在独立和自我协调，帮助更好地理解玻璃体作为可持续的聚合物和聚合物复合材料解决方案。这应通过系统调查和阐明导致延展性的过程来完成，首先是通过使用模型Vitrimer系统的热物理性质的准静态和动态(包括动态)方法。因此，申请者专注于材料科学、工程学和物理学之间的跨学科研究。

Vitrimers are a new class of polymers that combine the malleable character of thermoplastics with the extraordinary mechanical performances of highly cross-linked thermosets. The huge advantage of Vitrimers is, even though they are cross-linked, i.e. their molecular state being far beyond a structural percolation threshold, that they can be repaired, reshaped or even recycled. This is because of the presence of switchable molecular bonds. Hence, Vitrimers are not only sustainable, but also enable new perspectives on processing technologies, e.g. via repeated forming processes, as well as opportunities to enhance the lifetime and durability of polymer applications in service. However, from an engineering point of view, making use of the exciting Vitrimer properties currently lacks the understanding of the underlying physical and physio-chemical mechanisms. This is even more important in the case of Vitrimer-based composite materials, when additional physical and chemical interactions come into play, e.g. between fibres and a Vitrimer matrix. Within this research proposal, the early-stage postdoc and applicant to the Walter Benjamin programme aims to, independently and self-coordinated, contribute to a better understanding of Vitrimers as sustainable polymer and polymer composite solutions. This shall be done by a systematic investigation and elucidation of the processes that are responsible for the malleability, foremost by quasi-static and dynamic (including kinetic) means of thermo-physical properties, using a model Vitrimer system. Thereby, the applicant focusses on interdisciplinary research at the interface between materials science, engineering and physics.