Robust Biobased Vitrimers and Its Application to Closed-Loop Recyclable Carbon Fiber-Reinforced Composites

Vitrimers are being actively studied as sustainable plastics. To that end, robust vitrimer films fabricated from a ternary aqueous solution of tannic acid (TA), boric acid (BA), and polyvinyl alcohol (PVA) are reported herein. The trimeric vitrimer films include B-O-C dynamic covalent bonds. The optimal vitrimer film exhibits excellent crosslinking density (0.0471 mol/cm(3)), tensile strength (77 MPa), and modulus (3.2 GPa). A carbon-fiber-reinforced vitrimer (CFRV) was prepared with a vitrimer film and carbon fiber at temperatures above T v. The CFRV (tensile strength, 570 MPa; modulus, 21 GPa) can be used as a structural composite material. Additionally, it retains the unique recyclability and reprocessability of the vitrimer. The solution-cast film can be reproduced from the vitrimer solution prepared during recycling, and a CFRV similar to the original can be recreated by remolding the recovered carbon fiber with the reproduced vitrimer film. The synthesized biobased high-strength vitrimer films can facilitate the development of sustainable carbon-fiber-composite materials.