Readily Recyclable, Auto-Catalyzed Tung Oil-Derived Vitrimers and Carbon Fiber-Reinforced Composites

Abstract

The high strength and durability of carbon fiber-reinforced composites (CFRCs) have made them a popular choice in aerospace, civil engineering, and sports equipment. However, the non-degradable resin matrix and non-destructive recycling of carbon fibers present a challenge for their sustainability. To address this issue, we have developed a new type of CFRCs that are readily recyclable and high-performing, using an auto-catalyzed tung oil-derived vitrimer and acid curing agents (TTMA) in combination with bisphenol A epoxy resin (DGEBA) or 4,4′-methylene bis (N,N-di glycidylaniline) (TGDOM). The DGEBA/TGDOM-TTMA networks contain abundant ester bonds, hydroxyl groups, and tertiary amine, which can undergo dynamic transesterification reactions (DTER) at high temperatures, leading to topological rearrangement of cross-linked networks. This results in an epoxy resin matrix with excellent mechanical properties, thermostability, and easy reprocessing, self-healing, and degradation at elevated temperatures. Moreover, the TGDOM-TTMA exhibits good stress relaxation properties due to the high concentrations of hydroxyl and tertiary amine. Additionally, we have found that carbon fibers can be completely recycled from CFRCs using ethanolamine via amidation reaction, with the recycled carbon fibers maintaining nearly 100% of the mechanical properties of the virgin samples. This study offers a sustainable and convenient strategy for designing readily recyclable and high-performance CFRCs, with important implications for the future of composite materials.