Improvement of mechanical properties of carbon fiber plain weave fabric reinforced thermoplastic composites by constructing PPESK/PEEK complex interlayer phase using interlayer spraying method

Abstract Carbon fiber plain weave fabric (CFPWF) reinforced polyphthalazine ether sulfone ketone (PPESK) composites with weak interlaminar bonding are prone to delamination failure, resulting in poor mechanical properties. Therefore, this paper adopted the interlayer spraying process to construct the polyphthalazine ether sulfone ketone/polyether ether ketone (PPESK/PEEK) composite interlayer phase between the composite layers and adjusted the ratio of PPESK and PEEK to regulate the interlayer phase structures. The results indicated that when the ratio of PPESK to PEEK is maintained at 1:1, the composite interlayer phase exhibited a bicontinuous phase structure, resulting in optimal mechanical properties for the composites. The tensile strength was 477 MPa, representing increases of 30.79% and 8.82% compared to the pure PPESK and pure PEEK single interlayer phases, respectively. The flexural strength reached 338 MPa, indicating increases of 25.90% and 112.50% over the pure PPESK and pure PEEK single interlayer phases. Additionally, the maximum impact load recorded was 1978 N, with an energy absorption rate of 86.56%. Highlights Complex interlayer phase was constructed using an interlayer spraying process. Adjustment of the ratio of PPESK to PEEK‐regulated interlayer phase structures. The effect of interlayer phase structure on mechanical properties was explored.