Polymerization Catalysts for the Reversible Switching Between Vinyl Insertion and Ring-Opening Metathesis Polymerization

该项目的目标是设计，合成和评估新型过渡金属基引发剂，允许两种基于聚插入的机制之间的受控和多个可逆切换，即乙烯基插入（1-烯烃）聚合（VIP）和开环易位聚合（ROMP）。整个过程，即经由VIP和ROMP基机理的环烯烃聚合，应在无环烯烃例如乙烯或苯乙烯的存在下完成。乙烯基插入聚合和ROMP的程度应受温度控制。与合适的单体（乙烯、环戊烯、顺式环辛烯、降冰片-2-烯等）组合，和反应条件，这将允许合成前所未有的聚合物结构，优选具有短的不饱和（烯属）序列。这些将不仅影响所得聚合物的物理性质（Tm、Tg、杨氏模量），而且允许广谱的衍生化反应，所有衍生化反应都以后聚合反应的形式进行。在这方面，我们的目标是二卤化、氢卤化和环氧化/二羟基化反应以及接枝聚合，例如，通过受控自由基聚合技术，如原子转移自由基聚合（ATRP），并希望研究所得聚合物的性能。最后，如果适用，还应对聚合物进行基本纺丝实验。

The project goal is the design, synthesis and evaluation of novel transition metal-based initiators that allow for the controlled and multiple, reversible switching between two polyinsertion-based mechanisms, i.e. vinyl insertion (1-olefin) polymerization (VIP) and ring-opening metathesis polymerization (ROMP). The entire process, i.e. the polymerization of cyclic olefins via both a VIP and ROMP-based mechanism shall be accomplished in the presence of acyclic olefins, e.g. ethylene or styrene. The extent of vinyl insertion polymerization and ROMP shall be governed by temperature. In combination with suitable monomers (ethylene, cyclopentene, cis-cyclooctene, norborn-2-ene, etc.) and reaction conditions, this will allow for the synthesis of unprecedented polymer structures, preferably with short unsaturated (olefinic) sequences. These will not only influence the physical properties of the resulting polymers (Tm, Tg, Youngs Modulus, ), but also allow for a broad spectrum of derivatization reactions, all to be carried out in form of post-polymerization reactions. In this context, we aim at dihalogenation, hydrohalogenation and epoxydation/dihydroxylation reactions as well as graft polymerizations, e.g., via controlled radical polymerization techniques such as atom-transfer radical polymerization (ATRP) and wish to study the properties of the resulting polymers. Finally, if applicable, the polymers shall also be subjected to basic spinning experiments.