Process parameter-mechanical property relationships and influence mechanism of advanced CFF/PEEK thermoplastic composites

Process parameters, as the core factor to control the forming quality of composites, are crucial for the processing of composites. In this paper, plain-woven carbon fiber fabric reinforced polyether ether ketone (CFF/PEEK) thermoplastic composites are fabricated by hot-pressing process. Influence of the critical process parameters, including molding temperature, molding pressure and holding time, on mechanical properties of CFF/PEEK composites are investigated. The tensile, flexural and short-beam shear properties of CFF/PEEK composites fabricated by different process parameters were tested as evaluation indicators to achieve the optimization of process parameters. Most importantly, to deeply and systematically reveal the influence mechanism of process parameters, the high-temperature contact angle of CFF-PEEK and the viscosity-temperature characteristics of PEEK were observed and analyzed. In addition, the forming quality and microscopic failure modes of CFF/PEEK composites were observed by optical, metallographic and scanning electron microscopy, respectively. This work provides a research idea and technical route for studying the process parameters of fiber reinforced polymer composites and revealing their influence mechanism on mechanical properties.