Strong yet Tough Catalyst‐Free Transesterification Vitrimer with Excellent Fire‐Retardancy, Durability, and Closed‐Loop Recyclability

Abstract

Despite great advances in vitrimer, it remains highly challenging to achieve a property portfolio of excellent mechanical properties, desired durability, and high fire safety. Thus, a catalyst‐free, closed‐loop recyclable transesterification vitrimer (TPN1.50) with superior mechanical properties, durability, and fire retardancy is developed by introducing a rationally designed tertiary amine/phosphorus‐containing reactive oligomer (TPN) into epoxy resin (EP). Because of strong covalent interactions between TPN and EP and its linear oligomer structure, as‐prepared TPN1.50 achieves a tensile strength of 86.2 MPa and a toughness of 6.8 MJ m−3, superior to previous vitrimer counterparts. TPN1.50 containing 1.50 wt% phosphorus shows desirable fire retardancy, including a limiting oxygen index of 35.2% and a vertical burning (UL‐94) V‐0 classification. TPN1.50 features great durability and can maintain its structure integrity in 1 M HCl or NaOH solution for 100 days. This is because the tertiary amines are anchored within the cross‐linked network and blocked by rigid P‐containing groups, thus effectively suppressing the transesterification. Owing to its good chemical recovery, TPN1.50 can be used as a promising resin for creating recyclable carbon fiber‐reinforced polymer composites. This work offers a promising integrated method for creating robust durable fire‐safe vitrimers which facilitate the sustainable development of high‐performance polymer composites.