Composite Recycling\nwith Biocatalytic Thermoset Reforming

Carbon fiber reinforced polymers (CFRPs, or composites)\nare increasingly\nreplacing traditional manufacturing materials used in the automobile,\naerospace, and energy sectors. With this shift, it is vital to develop\nend-of-life processes for CFRPs that retain the value of both the\ncarbon fibers and the polymer matrix. Here we demonstrate a strategy\nto upcycle pre- and postconsumer polystyrene-containing CFRPs, cross-linked\nwith unsaturated polyesters or vinyl esters, to benzoic acid. The\nthermoset matrix is upgraded via biocatalysis utilizing an engineered\nstrain of the filamentous fungus Aspergillus nidulans, which gives access to valuable secondary metabolites in high yields,\nexemplified here by (2<i>Z</i>,4<i>Z</i>,6<i>E</i>)-octa-2,4,6-trienoic acid. Reactions are engineered to\npreserve the carbon fibers with much of their sizing so that the isolated\ncarbon fiber plies are manufactured into new composite coupons that\nexhibit mechanical properties comparable to those of virgin manufacturing\nsubstrates. In sum, this represents the first system to reclaim a\nhigh value from both the fiber fabric and polymer matrix of a CFRP.