Interpenetrating vitrimers based on dioxaborolane metathesis and imine-aldehyde exchange

Abstract

Due to their thermal and oxidative stability, compatibility with numerous chemical functionalities and ease of implementation in various polymer matrices, dioxaborolanes have proven to be dynamic covalent links of choice to design vitrimers. However, dioxaborolane metathesis can take place at room temperature, which can lead to elastomeric vitrimers with poor creep and solvent resistance at service temperature. In this study, we report the synthesis and characterization of interpenetrating vitrimers (IVs). These IVs consist of two interpenetrating vitrimers that rely on boronic ester metathesis and imine-aldehyde exchange, respectively. Model studies were conducted to evaluate the chemical orthogonality of the two vitrimer subnetworks and their contribution to the properties of the resulting IVs. Remarkably, the distinctly different dynamics and crosslinking densities of the two vitrimers enabled the preparation of IVs with superior thermal, solvent and creep resistance at service temperature. Additionally, we demonstrate that the IVs can be efficiently mechanically recycled without alteration of their thermomechanical properties.