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WEB Anomalous Bulk Diffusion Mechanism of Methylen Diphenylmethane-4,4′-diisocyanate in Cross-linked Poly(dimethylsiloxane)

In industrial applications of the vacuum casting process, silicone casting molds are used to replicate prototypes and small series made of poly(urethane) [1]. The undesired diffusion of the isocyanate component into the silicone leads to degradation of the casting tools [2]. In this contribution, we present a detailed description of the chemical and physical mechanisms of diffusion at the molecular level and the modelling of the anomalous bulk diffusion process. The polymerization of the methylen diphenylmethane-4,4′-diisocyanate with residual moisture to poly(urea) within the cross-linked poly(dimethylsiloxane) matrix leads to a time dependence of the diffusion coefficient and thus require more complex solutions to Fick’s 2nd law to describe the concentration distribution over time and cross-section.

[1] Strube et al. Polym.-Plast. Technol. 54, 494 (2015)

[2] Wortmann et al. Polym.-Plast. Technol. 57, 1524 (2017)


Dipl.-Ing. Martin Wortmann
Bielefeld University of Applied Sciences
Additional Authors:
  • Dr. Klaus Viertel
    Bielefeld University of Applied Sciences
  • Dr. Natalie Frese
    Bielefeld University
  • Prof. Dr. Elmar Moritzer
    Paderborn University
  • Prof. Dr. Armin Gölzhäuser
    Bielefeld University
  • Prof. Dr. Bruno Hüsgen
    Bielefeld University of Applied Sciences