Multi-scale modelling and validation of smart polymer composites

In recent times, innovative materials has played a central role in the development of new technologies, in many areas of application. In a rapidly changing world, the development of new materials is needed to meet today and tomorrow’s technological challenges. There are many examples, like electronic components, photovoltaic cells, fuel cells, storage systems just to name a few, for which the engineering of new materials opens the doors to the creation of new devices, or allows existing ones to improve their performance or efficiency. The development of new materials takes time and has a cost due to the effort on the research and the numerous tests that are necessary. The possibility of predicting the thermo-physical properties of a material with some precision, even if it is not yet commercially available, can be a very interesting prerogative. The aim of this work is to develop protocols for the estimation of thermo-physical properties starting from the chemical composition alone, by means of simulations of molecular dynamics (MD). The framework is the SMARTFAN European Project framework which involves several partners, companies and universities, including Politecnico di Torino, who is the leader of work package 5 (WP5), namely “Modeling-Enhanced continuum mechanics approaches (from atoms to continuum mechanics)”. This work consists in the mesoscale part of a nano- to-continuum multiscale study of an epoxy-based thermosetting polymer, which is of interest for one of the project’s partner company, specialized in motorsport applications. In particular, the goal is to define some procedures useful to characterize mechanical and thermal behaviour of this compound, by computing several thermo-physical property. Nanoscale atomistic simulations results are the input, from which a mesoscale coarse-grained model is carried out. Conversely, the outputs are computed thermo-physical properties, including stiffness matrix and thermal conductivity, suitable to characterize the material in future continuum simulations. In the first part, two literature reviews are presented . The first review is on the mesoscale MD models, including mapping, parametrization and simulation details for different methods focused on mechanical properties computation. The second review is on continuum models The second part is focused on coarse-graining (CG) procedures, starting from theoretical aspects then showing some CG models available in literature, all involving thermosetting epoxy resins. The third part deals with general information and theoretical aspects of the epoxy resin of interest for the project (DGEBA/DICY/DETA), including details on chemical structures, crosslinking process and general properties, in order to get an overview of the material subject of the simulation part. In the fourth part all the simulations activities are explained and results are shown and commented. Appendix A contains all the simulation details, including all the implemented scripts in human readable form, while Appendix B contains all the potential curves of the CG force field adopted.