Two-phase flow modeling of thermal frontal polymerization

Thermal frontal polymerization is a process that converts a monomer solution (liquid) into solid polymer via propagation of a reaction front. Initiated by a brief local energy source, the front is self-sustained by virtue of the heat generated by the polymerization reaction. Allowing for rapid and uniform synthesis, this process has gained interest as a fast and energy-efficient solution for manufacturing of composites. However, the front is subject to thermo-convective and chemical instabilities which can degrade the quality of the end polymer product and even extinguish the entire process. Currently, our understanding of the front dynamics is incomplete.

In this talk, we present a recently developed two-phase flow model that can provide a detailed view of the structure and dynamics of frontal polymerization. This model is based on a mixture-theoretic formalism that treats the liquid reactants and the solid polymer as two separate continuum systems that interact with one another. Further, it can accommodate both reduced and detailed chemical reaction mechanisms. In the first part of the presentation, we elaborate on the derivation and properties of this model and outline the computational method for its treatment. Finally, in the second part, we present numerical results from 2D simulations of the problem in hand in simplified geometries.