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We report a rapid route to reclaim carbon fiber (CF) fabric and monomeric chemicals from amine-epoxy CF-reinforced polymer (CFRP) composites. We use a reaction that occurs in molten NaOH- KOH eutectic to selectively cleave aryl ether and amine linkages, which involves two temperature-dependant mechanisms. Bisphenol-A is isolated in up to quantitative yields, and recovered CF fabric is remanufactured into 2nd-generation CFRPs. 

Carbon fiber reinforced polymers (CFRPs, or composites) are increasingly replacing traditional manufacturing materials used in the automobile, aerospace, and energy sectors. With this shift, it is vital to develop end-of-life processes for CFRPs that retain the value of both the carbon fibers and the polymer matrix. Here we demonstrate a strategy to upcycle pre- and post-con- sumer polystyrene-containing CFRPs, crosslinked with unsaturated polyesters or vinyl esters, to benzoic acid. The thermoset matrix is upgraded via biocatalysis utilizing an engineered strain of the filamentous fungus Aspergillus nidulans, which gives access to valuable secondary metabolites in high yields, exemplified here by (2Z,4Z,6E)-octa-2,4,6-trienoic acid. Reactions are engineered to preserve the carbon fibers, with much of their sizing, so that the isolated carbon fiber plies are manufactured into new composite coupons that exhibit mechanical properties comparable to virgin manufacturing substrates. In sum, this represents the first system to reclaim high value from both the fiber fabric and polymer matrix of a CFRP. 

Carbon fiber reinforced polymer (CFRP) composites are uniquely essential materials in the aerospace, automobile, energy, sporting, and an increasing number of other industries. Consequently, we are amassing an accumulation of CFRP waste latent in value. Electrochemical techniques to recycle carbon fiber reinforced polymers have recently emerged as viable methods to remove the composite matrix from these materials and recover fibers. In many of these techniques, the composite is immersed in a solvent and acts as an electrochemical anode while a voltage is applied to the electrolytic cell. Still, few methods leverage the conductivity of the composite to mediate its own disassembly. We have introduced an electrolytic method that leverages this conductivity to electrolyze acetic acid to form methyl radicals that cleave the C-N bonds of the epoxy matrix and cleanly separate ordered fibers from the matrix. This talk will discuss the motivation and development for this new electrochemical method and explain the chemical mechanism through which it works. 

We introduce an electrochemical approach to recycle carbon fiber (CF) fabrics from amine-epoxy carbon fiber-reinforced polymers (CFRPs). Our novel method utilizes a Kolbe-like mechanism to generate methyl radicals from CH 3 COOH to cleave C–N bonds within epoxy matrices via hydrogen atom abstraction. Recovered CFs are then remanufactured into CFRPs without resizing. 

This presentation will describe conditions for the use of oxygen as a reagent for the selective cleavage of thermoset composites. Carbon fiber-reinforced polymer (CFRP) composites have a prominent role in aviation, sporting goods, marine, and other manufacturing sectors and are accumulating en masse as waste, both at end-of-life and as manufacturing defects. We have recently introduced a method to use oxygen itself along with an appropriate catalyst selectively to disassemble such fully-cured composite wastes to recover both ordered carbon fiber sheets and organic materials suitable for re-manufacturing of second-life resin systems.