Vitrimers have emerged as an innovative class of polymeric materials that combine the robustness of thermosets with the reprocessability of thermoplastics through dynamic covalent bond exchange. While extensive research has focussed on their mechanical performance and processing conditions, the fundamental role of stoichiometric balance in vitrimer formulations remains underexplored. This review explores the influence of stoichiometry on vitrimer network formation, with a particular emphasis on bio-based epoxy vitrimer systems incorporating epoxidized vegetable oil (EVO). The impact of different epoxy-to-EVO and curing agent-to-EVO ratios on crosslinking density, thermal stability and self-healing characteristics are discussed in detail. The discussion includes the selection of curing agents, namely those with carboxyl (-COOH) and amine (-NH) functional groups, regarding their influence on vitrimer reactivity and recyclability. Notably, findings indicate that EVO-based vitrimer require lower catalyst loading compared to conventional epoxy-based vitrimer, contributing to more sustainable and cost-effective formulations. Understanding the stoichiometric interplay in vitrimer formulations is crucial for optimizing material performance, minimizing catalyst requirements and enhancing long-term durability. Resolving these stoichiometric problems is crucial for the growth of vitrimer applications in biodegradable composites and other high-performance industries.
Lee et al. (2025) studied this question.