Characterization and in-situ analysis of the cellular structure and foaming process of aerogel-polyurethane composites by means of X-ray radioscopy and tomography

Abstract

This master thesis is aimed at investigating the physical mechanisms occurring during the foaming process and the final cellular structure of a novel foamed composite system of aerogel/rigid foam polyurethane. For this purpose, two characterization techniques based on X-ray interaction with matter have been employed. As a result, both the in-situ monitoring of the foaming process and the ex-situ analysis of the foamed materials have been carried out. The in-situ experiments were focused on understanding the underlying phenomena affecting cell nucleation, growth and cellular structure stabilization, determining which are the main mechanisms governing the final cellular structure. Complementarily, the computation of classical and advanced cellular architecture descriptors allowed determining the progressive modification of the final cellular structure with the addition of aerogel and its relationship with the observed materials modification at the end of the recorded foaming process. Under this perspective, it will be possible to discern the influence of both nanoporous particles and their content, on the production of materials with a certain final cellular structure.