PU foams: Mathematical modelling of morphology development

In this paper we present mathematical model for the development of foam morphology during the reactive foaming of polyurethane (PU). The model describes the most important physical phenomena from reaction kinetics and diffusion of blowing agents to wall drainage by capillary forces. We implemented the end group model for the PU polymerization, a bubble–shell model for the bubble growth and foam expansion and thin film model for the evolution of the wall thickness profile. The combined model can thus simulate the evolution of foam density, bubble size and wall thickness based on the foam recipe. The model allows us study the effect of physical parameters on the final foam morphology, and thus on the foam application properties.