Reprocessable carbon fiber vitrimer composites: Reclamation and reformatting of carbon fibers for second generation composite materials

Carbon fibers (CFs) are experiencing a growing demand owing to their low
specific weight, exceptional mechanical properties, superior temperature, and
corrosion resistance, however, their sustainability and energy consumption
during manufacturing is still a challenge. Therefore, reclamation of waste CFs
and their reformatting has gained significant attention. Herein, we synthesized
a chemically degradable vitrimer matrix by curing bisphenol-A diglycidyl ether
(BADGE) with 2-aminophenyl disulfide (2-AFD) and further utilized the
matrix for the development of CF reinforced composites (CFRCs) through vac-
uum-assisted resin infusion molding (VARIM) process. The obtained vitrimeric
system and its composites show excellent mechanical, self-adhering, shape-
memory, and reprocessing properties. Meanwhile, the developed CFRP vitri-
mer composites can be rapidly dissolved in thiol solvent (1-octanethiol), result-
ing in the efficient recycling of CFs. X-ray diffraction, scanning electron
microscopy, and Raman spectroscopy validate that the chemical structure of
the recycled fibers closely resembles the structure of the original CFs. The
recycled CFs were further used to prepare second generation composite mate-
rials with excellent thermal, dynamic, and mechanical properties for nonstruc-
tural applications (e.g., sports, automotive, etc.). Thus, with an effective CF
recycling method, this study can assist in preparing reliable, long-term func-
tional, recyclable, and high-performance composites.