In this study, a novel CFRP made of PET (from Indorama Ventures Fibers Germany) reinforced with either virgin or recycled carbon fibers was characterized and degraded by an enzymatic process with prior pretreatment.
The characterization of the CFRP was carried out by bending and ILSS tests and showed that the CFRP made of virgin carbon fibers achieved properties, which were at the same level as the state of the art CFRP made of epoxy. The CFRP reinforced with recycled carbon fibers in the form of drylaid nonwovens showed overall reduced properties, but again similar results to epoxies reinforced with comparable nonwovens. In addition, both PET materials were degraded to different extents using the LCC-ICCG enzyme. In particular, after pre-treatment of the samples with sodium hydroxide solution, significant amounts of PET were degraded and SEM images confirmed the degradation, but with PET particles still attached to the carbon fibers.
Pretreatment was necessary to increase the available surface area for enzymatic degradation. Without any pretreatment the enzymatic degradation of PET was very slow and did not result in significant degradation. In addition, there is still work to be done to reduce the crystallinity of PET as this is an important factor for a sufficient enzymatic degradation reaction.  
The comparison of the CFRP made from virgin and recycled carbon fibers in terms of enzymatic degradation showed that the CFRP made from nonwoven (from recycled carbon fiber) was degraded faster because the available surface area is higher due to an increase in the height of the sample during pretreatment.
Thus, the overall results presented lead to the conclusion that especially the CFRP made from nonwovens with a thermoplastic PET matrix can be recycled by enzymes in the future. For CFRP made of virgin fibers, the available surface area is harder to increase and therefore the enzymatic degradation is not as efficient.