Stimuli‐Mild, Robust, Commercializable Polyurethane‐Urea Vitrimer Elastomer via N,N′‐Diaryl Urea Crosslinking

Abstract

AbstractVitrimer is a new reprocessable thermosetting polymer based on the exchange of dynamic covalent bonds. However, the vitrimer reported in the literatures can usually be reprocessed at very high temperature, while the vitrimer reprocessed at a relatively low temperature exhibits poor mechanical properties. It is still a great challenge to design mechanically robust vitrimer with a moderate reprocessing temperature. Herein, a polyurethane‐urea vitrimer elastomer including N,N′‐diaryl urea with electron donating effect is first reported, and it possesses a moderately remoldable temperature (100 °C, 23% of soft segments content) and robust mechanic al performance. The associative exchange mechanism of N,N′‐diaryl urea with electron donating effect is investigated by the stress relaxation, variable temperature Fourier transform infrared spectra of elastomer, as well as nuclear magnetic resonance spectra, and Fourier transform infrared spectra based on model compounds. Besides, for the preparation of polyurethane‐urea vitrimer elastomers, all monomers are directly from commercial raw materials, thereby providing a possibility of large‐scale production for the polyurethane‐urea vitrimers.