Carbon Fiber Reinforced Epoxy Vitrimer: Robust Mechanical Performance and Facile Hydrothermal Decomposition in Pure Water

Abstract

Conventional carbon fiber reinforced thermosetting polymers (CFRPs) are neither recyclable nor repairable due to their crosslinked network. The rapid growing CFRP market raises a serious concern of the waste management. In this work, a viable method to develop a readily recyclable CFRP based on epoxy vitrimer is introduced. First, a self‐catalytic epoxy prepolymer with built‐in hydroxy and tertiary amine groups is designed, which upon reaction with an anhydride formed a catalyst‐free epoxy vitrimer. The epoxy prepolymer is synthesized from a diamine and an excess of bisphenol A epoxy resin. The hydroxyls and tertiary amines of the epoxy prepolymer efficiently catalyze both curing and the dynamic transesterification of the crosslinked polymer without the need of a catalyst. Then, the epoxy vitrimer is used as the matrix resin to prepare CFRP. The resulting CFRP exhibited a tensile strength as high as 356 MPa. More interestingly, the matrix of the CFRP is efficiently degraded in pure water at above 160 °C. This is because the built‐in tertiary amines catalyze the hydrolysis of the ester bonds of the crosslinked network. The simple method developed in this work provides a framework for the development of recyclable CFRP.

Reprocessable, Self-Adhesive, and Recyclable Carbon Fiber-Reinforced Composites Using a Catalyst-Free Self-Healing Bio-Based Vitrimer Matrix

“…In contrast to previous reports, we found that TOTGE–MDA vitrimers can undergo the DTER without the need for additional catalysts. This is because the reaction of TOTGE with MDA generates a large number of β-hydroxy esters and tertiary amines, which act as catalysts and allow the vitrimers to undergo the DTER and achieve the topological rearrangements previously reported. , …”

“…The catalysts of DTERs are toxic, poorly compatible, and sensitive to corrosion. − Therefore, the development of catalyst-free vitrimers based on a DTER is of great importance. The introduction of tertiary amines into the vitrimer network is an effective solution. , Zhang’s group introduced triethanolamine as a co-curing agent into a DER331 epoxy resin and anhydride network. The vitrimer network underwent a rapid DTER and achieved self-healing catalyzed by tertiary amine in triethanolamine.…”

“…The vitrimer network underwent a rapid DTER and achieved self-healing catalyzed by tertiary amine in triethanolamine. Further, ethylenediamine and glutaric anhydride were used as curing agents for DER331, yielding vitrimer matrices with tertiary amines . The matrices of CFRCs were degradable in pure water catalyzed by tertiary amines.…”

“…The introduction of tertiary amines into the vitrimer network is an effective solution. 39,43 Zhang's group 39 introduced triethanolamine as a co-curing agent into a DER331 epoxy resin and anhydride network. The vitrimer network underwent a rapid DTER and achieved self-healing catalyzed by tertiary amine in triethanolamine.…”

Study into the Mechanical Properties of a New Aeronautic-Grade Epoxy-Based Carbon-Fiber-Reinforced Vitrimer

“…Over the past years, several vitrimer composites with diverse synthetic or natural monomers and dynamic formulations have been applied in continuous glass or carbon fiber reinforcements, showing promising mechanical properties compared to their thermoset counterparts [ 6 , 10 , 19 , 20 , 23 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. Some vitrimer formulations have attractive properties such as a high tensile strength, interlaminar shear strength or glass transition temperatures [ 6 , 23 ].…”