Hyperbranched polyester catalyzed self-healing bio-based vitrimer for closed-loop recyclable carbon fiber-reinforced polymers

Closed-loop recycling in the matrix resin and carbon fibers (CFs) of carbon fiber-reinforced polymers (CFRPs) is a major challenge. To solve this problem, herein, a closed-loop recyclable vitrimer matrix containing hydroxyterminated hyperbranched polyesters (HBPs), rosin-derived fumaropimaric acid (FPA), and glycerol triglycidyl ether (GTE) is prepared. The FPA/GTE/HBP vitrimers exhibited excellent mechanical properties owing to the highly reactive hydroxyterminated HBP and rigid FPA. The abundant hydroxyl groups of HBP catalyzed the dynamic transesterification reaction of the vitrimer network, resulting in self-healing and reprocessing proper-ties. In addition, FPA/GTE/HBP-CF composites exhibited high mechanical strength and interlayer shear strength owing to the presence of HBP. FPA/GTE/HBP15-CF was degraded by ethylene glycol during the catalytic operation of the hydroxy-terminated HBP, and the degraded matrix could be closed-loop recycled. Scanning electron microscopy, Raman analysis, and tensile testing showed that the degradation reaction did not degrade the properties of the recycled CFs. This study presents an environmentally-friendly strategy for pre -paring closed-loop recyclable CFRPs.

Automated summary

This study presents a closed-loop recyclable vitrimer matrix system, which is prepared using hydroxyterminated HBPs, FPA, and GTE and exhibits excellent mechanical properties. The addition of HBP in the polymer matrix enhances the mechanical strength and interlayer shear strength of CF composites.