Matrix Decomposition of Carbon-Fiber-Reinforced Plastics via the Activation of Semiconductors

Abstract

The present study proposed a novel process for the matrix decomposition of carbon-fiber-reinforced plastics (CFRPs). For this purpose, the influence of ultraviolet (UV) radiation paired with semiconductors on CFRP was analyzed. Then, suitable process parameters for superficial and in-depth matrix decomposition in CFRP were evaluated. The epoxy resin was decomposed most effectively without damaging the embedded carbon fiber by using a UV light-emitting diode (LED) spotlight (395 nm, Semray 4103 by Heraeus Noblelight) at a power level of 66% compared to the maximum power of the spotlight. Using a distance of 10 mm and a treatment duration of only 35–40 s achieved a depth of two layers with an area of 750 mm2, which is suitable for technological CFRP repair procedures. In addition to the characterization of the process, the treated CFRP samples were analyzed based on several analytical methods, namely, light microscopy (LM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Subsequently, the prepared carbon fibers (CFs) were tested using filament tensiometry, single filament tensile tests, and thermogravimetric measurements. All analyses showed the power level of 66% to be superior to the use of 96% power. The gentle (“fiber friendly”) matrix destruction reduced the damage to the surface of the fibers and maintained their properties, such as maximum elongation and maximum tensile strength, at the level of the reference materials.

Cost-Effective and Facile Fabrication of a Tattoo Paper-Based SERS Substrate and Its Application in Pesticide Sensing on Fruit Surfaces

“…In addition, not only could the substrate be damaged, but also the AgNPs could be aggregated together or separated from the substrate, which would degrade the performance of the SERS substrate. Thus, we used irradiated UV light, which is another well-known method for decomposing carbon compounds [ 42 , 43 , 44 ]. Moreover, AgNPs used as SERS particles can also act as a catalyst for carbon decomposition [ 45 , 46 ].…”

Novel Repair Procedure for CFRP Components Instead of EOL

“…The process products are carbon dioxide and water, and the CF remains intact. Further details concerning the matrix dissolution are the focus of earlier research activities, as described in [ 16 ]. The oxide-radical matrix removal process causes a discoloration that appears during the preparation of the repair site.…”

“…Therefore, the procedure is equal to the ‘Matrix-repair’ ( Section 2.2.1 ) at the start. The repair area is determined, and the matrix is decomposed out of the composite [ 16 ]. The defect fibers remain in a textile condition.…”

“…Recent research efforts have been focused on the development of a repair process based on oxide semiconductor-supported matrix degradation. In the affected area, the matrix can be removed by an ultraviolet (UV) irradiation-initialized degradation mechanism, so-called depolymerization [ 16 ]. This process can be used for two scenarios: ‘Matrix-repair’ can be used if the damage of the composite is narrowed to the matrix and the fibers are all intact.…”

Investigation of the Bonding Mechanism between Overlapping Textile Layers for FRP Repair Based on Dry Textile Patches

“…Recent research efforts [ 19 , 20 ] focused on the development of repair processes specially adapted to FRP. Therefore, the damaged fiber scaffold of the composite parts has to be fixed with new fibers in a different way to state-of-the-art procedures because, normally, the repair procedure is not basically carried out at the composite in total and is not focused on the textile scaffold.…”