Pre-compositing polyetherketoneketone with short-cut carbon fibers into advanced powder materials toward composites with fully-adhered interfaces

Abstract

It is challenging to realize intimate interface between reinforcement and matrix using powder materials, due to the high melting points and melt viscosities of thermoplastics like polyaryletherketones. Herein, a solution-based strategy is proposed to realize pre-composition in powders, and using them, full and tight fiber–matrix bounding is formed in the final composites. Owing to the dissolubility of polyetherketoneketone (PEKK), short-cut carbon fibers (CFs) are uniformly introduced into the solution and fully covered by PEKK, i.e., the pre-composition. The composite powders lead to structural uniformity, full utilization of CF surfaces, and avoidance of CF aggregation. The hot-compressed beams exhibit remarkably enhanced tensile and flexural strengths (135.5 and 173.7 MPa), more than 30% and 60% higher than those of the pure PEKK. Meanwhile, they possess high tensile and flexural strains at break up to 5.5% and 11.4%, respectively, enhanced crystallinity up to 17.7%, and high thermal conductivity of 0.26–0.29 Wm−1K−1. The pre-composition also exhibits other advantages, such as the higher powder flowability, reduced steps of high-temperature processing, and superior anti-abrasion ability and enhanced thermal stability of composite beams.