Regensburg 2022 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 17: Poster 2
CPP 17.39: Poster
Tuesday, September 6, 2022, 11:00–13:00, P2
Anomalous Diffusion of Diisocyanate in Cross-linked Silicone — •Martin Wortmann1, Klaus Viertel2, Natalie Frese1, Waldemar Keil3, Claudia Schmidt3, and Bruno Hüsgen2 — 1Bielefeld University, Bielefeld, Germany — 2Bielefeld University of Applied Sciences, Bielefeld, Germany — 3Paderborn University, Paderborn, Germany
In industrial applications of polyurethane vacuum casting, silicone casting molds are used to replicate complex three-dimensional master patterns for prototypes and small series production. The undesired diffusion of isocyanate from the casting resin into the silicone causes gradual degradation of the casting molds. In this contribution, we present mathematical models for the anomalous diffusion process and a comprehensive description of the underlying chemical and physical mechanisms. The polymerization of the isocyanate with residual moisture to polyurea within the silicone matrix leads to a time dependence of both the surface concentration and the diffusion coefficient. The resulting concentration distribution over time and cross-section is modelled by analytical solutions to the diffusion equation.