Rheological and crystallization behaviors of low processing temperature poly(aryl ether ketone)

A new low melting temperature poly(aryl ether ketone) (PAEK) thermoplastic polymer (Victrex AE 250) was investigated through thermal and rheological analysis of films and flakes. DSC was assigned to evaluate the influence of cooling rate on crystallinity and thermal transitions. Rheometry was used to assess its flowing behavior through the evaluation of dynamic moduli and complex viscosity in the melted state. The relaxation times were found from the rheological curves: they are between a few ms to 200 ms for AE 250, lower than those found for PEEK 450, meaning a faster mobility of macromolecules. The thermal activation energy, Ea obtained from Time Temperature Superposition is the same for films and flakes in spite of a lower viscosity for flakes. The molecular weight between entanglements is evaluated at 8000 g.mol−1 for FMc and 13,000 for FLc, it is compared to the value of about 2000 g.mol−1 found for PEEK 450 with the same procedure. Also, the viscosity was compared to other commercial PAEK such as PEEK and PEKK based on data from the literature. This polymer appears very efficient to compete with high performance thermoplastics to be processed by compression molding, out of autoclave consolidation, additive manufacturing, and welding. The new low melting temperature poly(aryl ether ketone) PAEK 250 appears as a promising high performance thermoplastic polymer. Its temperature processing ranges between 320 and 400°C, lower than current PAEK. Its rheological properties are compared to other commercial PAEK. Its viscosity and activation energy are similar to some grades of PEKK, and below those of PEEK. For this reason, PAEK 250 fits processing techniques such as compression molding, out‐of‐autoclave consolidation, additive manufacturing and welding.