Reusing recycled fibers in high-value fiber-reinforced polymer composites: Improving bending strength by surface cleaning

Glass fiber-reinforced polymer (GFRP) composites and carbon fiber-reinforced polymer (CFRP) composites were recycled using superheated steam. Recycled glass fibers (R-GFs) and recycled carbon fibers (R-CFs) were surface treated for reuse as fiber-reinforced polymer (FRP) composites. Treated R-GFs (TR-GFs) and treated R-CFs (TR-CFs) were characterized by scanning electron microscopy (SEM) and remanufactured by vacuum-assisted resin transfer molding (VARTM). Most residual resin impurities were removed by surface treatment. Analysis indicated no adverse effect of surface treatment on bending strength. The mechanical properties of the TR-GF reinforced polymer (TR-GFRP) and TR-CF reinforced polymer (TR-CFRP) composites were determined and compared with those of R-GF reinforced polymer (R-GFRP) and R-CF reinforced polymer (R-CFRP). The bending strengths of R-GFRP (26%) and R-CFRP (49%) were very low, compared to that of virgin glass fiber-reinforced polymer (V-GFRP) and that of virgin carbon fiber-reinforced polymer (V-CFRP). The bending strength of TR-GFRP composites was improved to about 90% of that of V-GFRP, and the bending strength of TR-CFRP composites was improved to about 80% of that of V-CFRP.