Dynamic rheological behavior of poly(ether ketone ketone) from solid state to melt state

Abstract

High performance thermoplastic poly(ether ketone ketone) (PEKK) polymers with various meta phenyl links ratio were investigated by dynamical mechanical analysis. Analyses were carried out in a wide range of temperature from solid state (torsion rectangular mode) to the melt state (torsion parallel plates mode) as function of thermal history and environmental conditions. In the solid state, this study was focused on the secondary relaxations in the vitreous state. A complementary investigation conducted with different poly(aryl ether ketones) allowed us to propose a molecular interpretation of PEKK sub-vitreous relaxations. In the molten state, storage modulus (G0), loss modulus (G00), storage viscosity (h0), and loss viscosity (h00) were studied to determine zero shear-rate viscosity (h0) and thermal activation energy Ea. Master curves were built and the shift factor aT was determined. Thermal activation energies were extracted from an Arrhenius model on the shift factor temperature’s dependency. Finally, Ea and h0 were determined thanks to the dynamic viscosity fit with Cross model and Cole–Cole representation