Optimization of process parameters of recycled carbon fiber-reinforced thermoplastic prepared by the wet-laid hybrid nonwoven process

The wet-laid hybrid nonwoven process can produce affordable carbon fiber-reinforced thermoplastic (CFRTP) because of its process simplicity, which can promote the application of CFRTP products in automobile weight reduction. The wet-laid hybrid nonwoven process involves two procedures, mainly: prepare preforms by a papermaking-like process and heat-molding compression. The parameters of heat-molding compression affect the quality of CFRTP directly, but there are not enough researches focusing on the effects of heat-molding compression parameters. This study aims to optimize the wet-laid hybrid nonwoven process to prepare recycled CFRTP. A proper carbon fiber content was determined firstly. Then, response surface methodology was used to optimize the heat-molding compression parameters. The effects of fiber length on composite properties were also investigated. The results showed that the fiber content of 30 wt% was the most suitable. The optimized heat-molding conditions were temperature, pressure, and time of 190°C, 2 MPa, and 10 min, respectively, leading to the lowest void content of 0.9%. CFRTP comprising carbon fibers with a length of 6 mm had the best properties, with the tensile strength of 59.34 MPa and flexural strength of 145.91 MPa.