Internally Catalyzed Polarized C═C Vitrimers

Vitrimers synthesis or processing usually relies on external catalysts to accelerate the chemical reactions involved. However, these catalysts often pose challenges such as toxicity, immiscibility, leaching, and deactivation over time. In this study, we developed internally catalyzed polarized C═C vitrimers by integrating tertiary amine structures into the polymer networks directly, enabling rapid topology network rearrangement while addressing the issue of catalyst failure. Small-molecule model reactions validated that the efficiency of the polarized C═C/active methylene group exchange was significantly improved under the catalysis of a tertiary amine. Afterward, a trifunctional active methylene compound with a built-in tertiary amine was synthesized and used as an internal catalyst as well as a coreactive monomer for the development of polarized C═C vitrimers. Compared to the noncatalyzed counterpart, polarized C═C vitrimers with a 10 mol % internal catalyst could reduce stress relaxation time by 2 orders of magnitude and topological freezing temperature by 46 °C. Moreover, the efficient internal catalysis enabled polarized C═C vitrimers to exhibit good reprocessability with consistent thermal and mechanical properties.