Stress‐induced dynamics of glassy vitrimers with fast bond exchange rate

Abstract

AbstractVitrimers are dynamic covalent networks, showing considerable promise in self‐healing and reprocessability applications. In this work, molecular simulations are used to study the shear stress‐induced dynamics of vitrimers in the glassy regime and compare their response with that of permanent networks, providing valuable insights into the macroscopic properties of these networks. Results show that vitrimers undergo bond exchange reactions induced by the application of the shear stress, and these events result in accelerated dynamics and subsequently, higher shear compliance of vitrimer compared to the thermoset. When the applied shear stress is high and deformation enters the nonlinear regime, the vitrimer network shows large shear creep compliance and enhanced non‐affine dynamics. Furthermore, the analysis of the self‐particle dynamics demonstrates that the dynamical behavior of vitrimers is highly heterogeneous at short observation times under low and intermediate stress values, while they become homogeneous in the regime of the shear compliance where it shows significantly higher compliance than the permanent network. The significance of the rate of deformation on the dynamics of glassy vitrimers is successfully demonstrated.