Evolution of mechanical properties of aged poly(ether ketone ketone) explained by a microstructural approach

Abstract

In this work, the thermo-oxidative behavior of PEKK films (~50 μm thick) in solid state were investigated. Since the mechanical properties of PEKK samples, especially the strain at break, are clearly affected after long ageing time, the modifications of the PEKK structure have been monitored at the molecular and the macromolecular scales using different techniques such as gel permeation chromatography, X-Ray scattering, differential scanning calorimetry, and dynamic mechanical analysis. If the embrittlement of the PEKK specimens seems to appear due to a predominant branching/cross-linking phenomenon occurring at the macromolecular scale, crystalline morphology is also slightly modified due to a chain scission mechanism occurring simultaneously.

Thermal oxidation of acrylonitrile-butadiene-styrene: Origin of the ductile/brittle transition

“…4 with scissions outnumbering crosslinks [43]. However, in the case of polymers having a glassy state such as PEKK, Roland et al have pointed out that embrittlement occurring during thermal oxidation is due to a predominant crosslinking over chain scission [44]. In our case, ABS has a biphasic morphology composed of SAN and PB phases which is exhibited during thermal oxidation chain scission and crosslinking mechanism respectively.…”