Degradation of constitutive response to mass loss: Predicting hydrolytic aging in vitrimers via reaction-modified transient network theory

Document Type

Article

Publication Date

7-2026

Department

Department of Mechanical and Aerospace Engineering

Abstract

Vitrimers are a subclass of thermosetting polymers with unique self-healing and recycling capabilities. Long-term hydrolytic aging of glassy vitrimer networks leads to progressive ester bond scission, mass loss, and mechanical degradation over time, yet a predictive constitutive framework linking chemical degradation to macroscopic response remains limited. In this work, we present a thermodynamically consistent, coupled physics model that combines reaction kinetics, water diffusion, and the transient deformation mechanics to characterize hydrolysis-driven degradation in glassy vitrimers. The framework introduces two forms of kinetic evolution of the extent of reaction-among which an empirical ester-concentration-based form is adopted and calibrated based on the experimental FTIR measurements of ester decay in a hydrolyzed epoxy-anhydride vitrimer. The governing equations are implemented in a finite-element setting via a user element subroutine (UEL) in ABAQUS/Standard (Dassault Systèmes, 2022), enabling fully coupled simulations of reaction-diffusion-mechanical processes. Upon careful parameter selection, the model predictions demonstrate good agreement with experimental results for aged samples’ constitutive response under quasi-static loading and long-term relaxation, reflecting an altered relaxation behavior, and increasing embrittlement associated with hydrolysis. Beyond macroscopic responses, the framework provides a statistically motivated description of microstructural degradation by linking hydrolysis-driven chain scission to the evolution of the local chain-length distribution. This approach enables the prediction of regions susceptible to void nucleation and material removal without prescribing explicit void geometry. Overall, the proposed framework connects chemical degradation, altered network dynamics, and microstructural void evolution, providing a predictive tool for determining the long-term sustainability of glassy vitrimers in hydrolytic environments.

Publication Title

Journal of the Mechanics and Physics of Solids

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