Design of crystallisation-inhibited polymer networks for absorption and storage of high mechanical impacts

蜘蛛使用拖丝作为坠落时的安全绳，也用来捕捉快速飞行的昆虫。这种拉铲能够吸收和耗散巨大的动能。到目前为止，还没有合成材料能够匹配蜘蛛拖丝的这些机械特性。本项目的目标是设计一种合成材料，该材料能够模仿蜘蛛拖丝在动能吸收方面的机械特性。我们提出，这是可以实现的材料，将自己从一个无定形的，橡胶状到一个高度结晶，高模量的状态下拉伸到大的伸长率，并保留后者后，消除拉伸力。为了避免误解：这个建议不是关于蜘蛛丝，而是关于一种具有高动能吸收能力的合成材料。冷编程形状记忆聚合物（SMP）是有希望的候选人，以满足相应的要求。因此，我们将专注于制备，表征和优化的新型结晶抑制聚合物网络，在室温下保持无定形和结晶应变诱导变形。在形状记忆天然橡胶（SMNR）和形状记忆聚乙烯（SMPE）的前期工作中，首次获得了令人满意的结果。在该项目中，将优化基于天然橡胶的SMP，并将制备基于间同立构聚丙烯（sPP）和聚异丁烯（PIB）等聚合物的新型网络，这些网络允许大应变，大结晶度和结晶速率，以最大限度地提高能量吸收能力并最大限度地减少弹性反弹。

Spiders use draglines as safety-lines in the event of a fall as well as for catching fast flying insects. Such draglines are capable of absorbing and dissipating tremendous amounts of kinetic energy. So far there is no synthetic material that matches these mechanical characteristics of spider dragline silk.The goal of this project is the design of a synthetic material that is capable of mimicking the mechanical properties of spider draglines with regard to its kinetic energy absorption. We propose that this is achievable by a material that transforms itself from an amorphous, rubber-like into a highly crystalline, high-modulus state upon stretching to large elongations and retains the latter after removing the stretching force. To avoid misunderstandings: This proposal is not about spider silk but deals with a synthetic material with high kinetic energy absorption capability. Cold-programmable shape memory polymers (SMPs) are promising candidates to meet the corresponding requirements. Thus we will focus on the preparation, characterization and optimization of novel crystallization-inhibited polymer networks that stay amorphous at room temperature and crystallize strain-induced upon deformation. First satisfactory results could be acquired from preliminary works on shape memory natural rubber (SMNR) and shape memory polyethylene (SMPE). In this project, SMPs based on natural rubber will be optimized and novel networks based on polymers like syndiotactic polypropylene (sPP) and polyisobutylene (PIB) will be prepared that allow large strains, large crystallinity, and crystallization-rates in order to maximize the energy absorption capacity and minimize the elastic rebound.