Vitrimers are chemically crosslinked networks that can rearrange their topology without decreasing their crosslinking density thanks to exchangeable links present in the network.^1,2 As a result, vitrimers can be potentially reshaped and recycled at will, while displaying the superior properties of crosslinked polymers at service temperature.

Very promising materials to create a circular economy of plastics and polymeric materials, vitrimers still display limitations that impact their transition towards industry, such as high viscosity even at elevated temperatures, due to the Arrhenian temperature dependence of the melt viscosity, or moderate creep resistance at working temperatures in the case of low T_g materials.^3,4

Although many strategies have been reported to address these issues, it remains challenging to overcome a key tradeoff between improving the processability or the mechanical performance of vitrimers. In this lecture, new strategies relying on phase separation and reactive processing will be presented to jointly improve the processability and the mechanical performance of vitrimers relying on dioxaborolane metathesis.⁵

References:

1. Montarnal, D.; Capelot, M.; Tournilhac, F.; Leibler, L. Silica-Like Malleable Materials from Permanent Organic Networks. Science 2011, 334, 965–968. https://doi.org/10.1126/science.1212648.
2. Van Zee, N. J.; Nicolaÿ, R. Vitrimers: Permanently Crosslinked Polymers with Dynamic Network Topology. Prog. Polym. Sci. 2020, 104, 101233. https://doi.org/10.1016/j.progpolymsci.2020.101233.
   
3. Guerre, M.; Taplan, C.; Winne, J. M.; Du Prez, F. E. Vitrimers: Directing Chemical Reactivity to Control Material Properties. Chem. Sci. 2020, 11, 4855–4870. https://doi.org/10.1039/D0SC01069C.
4. Breuillac, A.; Kassalias, A.; Nicolaÿ, R. Polybutadiene Vitrimers Based on Dioxaborolane Chemistry and Dual Networks with Static and Dynamic Cross-Links. Macromolecules 2019, 52, 7102–7113. https://doi.org/10.1021/acs.macromol.9b01288.
5. Röttger, M.; Domenech, T.; van der Weegen, R.; Breuillac, A.; Nicolaÿ, R.; Leibler, L. High-Performance Vitrimers from Commodity Thermoplastics through Dioxaborolane Metathesis. Science 2017, 356, 62–65. https://doi.org/10.1126/science.aah5281.