Investigating the mechanistic role of internal catalysts in the synthesis and (re)processing of adaptable polyurethane networks

• Applicant: Professorin Dr. Seema Agarwal
• Subject Area: Preparatory and Physical Chemistry of Polymers ; Polymer Materials
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 576071977

A comprehensive understanding of the strategic chemical modifications to the exchangeable carbamate bonds' environment in polyurethane-based vitrimers is aimed at enabling dynamic bond exchanges necessary for processing and recycling without external catalysts and side reactions, as well as understanding the mechanistic aspects of these bond exchanges. Specifically, the idea is to integrate internal catalysts (both acid and base types) that are covalently attached to cross-linked polyurethane (PU) structures, enabling dynamic bond exchanges via associative mechanism without side reactions at high processing temperatures. The mechanistic aspects of these exchange dynamics will be investigated in detail using different polymer backbone structures, varying cross-link densities, appropriate low molecular weight model compounds, and control experiments. To achieve this, synthetic routes will be established for the preparation of new diols, cross-linked polyurethanes with integrated catalysts, as well as for model compounds, followed by structural characterization. Dynamic mechanical thermal analysis and rheology will be primarily used to study stress-relaxation and vitrimer behavior. Vitrimers will also be characterized for their thermal and mechanical properties. Finally, stress relaxation, (re)processability, mechanical characteristics, and thermal behavior will be correlated to polymer structure, cross-link density, and the type and amount of internal catalysts. This will help generalize design rules for cross-linked processable PUs with a broad range of property profiles.

• DFG Programme: Research Grants