Spark plasma sintering and mechanical properties of two grades of PEKK presenting different Tere/Iso ratios

Abstract

Two grades of PolyEtherKetoneKetone with different Tere/Iso ratios (PEKK 60/40 and PEKK 80/20) were consolidated using spark plasma sintering. Processing parameters were varied and their influence on mechanical properties was assessed. The study reveals that sintering at a temperature close to the melting temperature along with an applied pressure of 18 MPa leads to better mechanical properties, while the effect of dwell time remains limited. A high sintering pressure is shown to promote the cohesion of PEKK 60/40 samples when the temperature is closer to the glass transition temperature, while pressure does not play a significant role for PEKK 80/20. Post‐mortem fractographic analyses provide explanations of the underlying phenomena. PEKK samples sintered with optimal processing parameters display higher compressive yield strength and stiffness than PEKK samples elaborated from conventional processing routes. They however also exhibit a fragile behavior which can be attributed to the incomplete healing between the powder particles.