Application of atomistic simulations to create a Quantitative Structure Property Relationship (QSPR) for predicting the environmental stress cracking of amorphous thermoplastics

该研究项目的目的是利用原子模拟建立定量结构性能关系来预测非晶态热塑性塑料的环境应力开裂。在其应用中，塑料部件会接触大量的液体环境介质，这些介质会显著影响其性能。这种影响目前在部件设计中不能考虑或仅考虑得不够，从而危及技术塑料部件的功能实现。环境介质对材料的影响是非常多样的，通常作用于原子尺度。最常见的失效原因是所谓的环境应力开裂，其描述了聚合物材料在机械载荷下同时暴露于液体环境介质的过早失效。在没有介质影响的情况下，导致失效的应力有时可能远低于机械载荷极限。在部件开发过程中考虑介质影响目前主要是通过时间和成本密集型实验来满足的，这些实验必须针对每种可能的塑料/介质组合进行。这激发了计划中的项目，该项目旨在开发和验证不同材料特性与环境应力开裂相关老化行为相结合的数学模型。为了构建这个数学模型，它被称为定量结构性质关系，原子模拟主要以分子动力学模拟的形式使用，以便能够在原子尺度上表示介质的上述影响。

The aim of the research project is to establish a Quantitative Structure Property Relationship using atomistic simulation to predict the environmental stress cracking of amorphous thermoplastics.In their application, plastic components come into contact with a large number of liquid environmental media, which can significantly influence their properties. This influence can currently not or only insufficiently be considered in the component design, whereby the functional fulfillment of technical plastic components is endangered. The influence of the ambient medium on the material is very diverse and usually acts on the atomistic scale. The most frequent cause of failure is the so-called environmental stress cracking, which describes the premature failure of a polymeric material under mechanical load with simultaneous exposure to a liquid environmental medium. It is characteristic that the stress leading to failure can sometimes be well below the mechanical load limits without media influence.The consideration of the media influence during component development is currently mainly met with time- and cost-intensive experiments, which have to be carried out for every possible plastic/media combination. This motivates the planned project, which aims at the development and validation of a mathematical model for the combination of different material properties with the resulting ageing behaviour regarding the environmental stress cracking. For the construction of this mathematical model, which is called Quantitative Structure Property Relationship, atomistic simulations are mainly used in the form of molecular dynamics simulations in order to be able to represent the mentioned influence of the medium on the atomistic scale.