Synthesis and Mechanical Properties of Linear and Long-Chain Branched Homopolymer Topologies via Modular Ligation

目前的延期请求建立在DFG过去三年资助的关于“Verarbeitungseigenschaften基金Stabilität von RAFT-basierten和模块化合成聚合物变量拓扑”主题的工作基础上。在请求的扩展范围内，我们希望利用我们已有的专业知识来实现两个定义明确的后续目标：(i)建立通过快速有效的光化学反应（光诱导点击化学）产生的新型模块化结扎点的热力学行为，但其在加工条件下的稳定性从未被评估过。获得用于构建嵌段共聚物的这种连接性（这里是焦唑啉和苯并异吲哚二酮）的稳定性数据，对于它们在将进行加工的材料中的适用性至关重要。此外，这些光化学生成的结扎点通常用于表面的图案，并且可以将大量获得的稳定性信息转移到几乎不可能直接获得的表面上。（ii）基于我们在之前的资助中获得的关于稳定性和加工条件的知识，我们将利用本项目中合成的不同定义良好的拓扑结构作为模型系统来研究具有越来越多分支点的复杂大分子结构的机械行为。流变学表征将在线性和非线性体制下的振荡剪切（老挝）和单轴延伸下进行，伴随着本构模拟（MSF和pomm -pom）和模拟使用小型挤出机（5克容量）的加工条件。为了实现上述目标，我们与精密聚合物化学（Barner-Kowollik教授）和流变学表征（Wilhelm教授）的专业知识互补，建立了一个连贯的联盟，用于合成聚合物材料。

The current extension request builds on the work of the past 3 years funded by the DFG on the topic of "Verarbeitungseigenschaften und Stabilität von RAFT-basierten und modular synthetisierten Polymeren variabler Topologie". Within the requested extension, we wish to exploit our established expertise to achieve two well-defined and clear subsequent aims: (i) Establish the thermomechanical behavior of a new class of modular ligation points that are generated via rapid and efficient photochemical reactions (photo induced click chemistry), yet whose stability under processing conditions has never been assessed. Having access to stability data of such connectivities (here pyrozolines and benzoisoindolediones), which are employed to construct, for example, block copolymers, is of critical importance for their applicability in materials that will undergo processing. In addition, these photochemically generated ligation points are often employed to pattern surfaces and stability information obtained in bulk can be transferred to surfaces, too, on which it is near impossible to obtain directly. (ii) Based on our knowledge obtained in the previous grant regarding the stability and processing conditions we will utilize the different well-defined topologies synthesized in this project as model systems to investigate the mechanical behavior of complex macromolecular architectures with an increasing number of branching points. The rheological characterization will be conducted under oscillatory shear in the linear and non-linear regime (LAOS) and under uniaxial elongation, accompanied by constitutive simulations (MSF and pom-pom) and mimicking of processing conditions using small scale extruders (5 g capacity). To achieve the above aims, we forge a coherent consortium with complementary expertise in precision polymer chemistry (Prof. Barner-Kowollik) for the synthesis of the polymeric materials and expertise in rheological characterization (Prof. Wilhelm).