Experimental correlation of rheological relaxation and interface healing times in welding thermoplastic PEKK composites

Julien Avenet (1) , Thomas A Cender (2) , Steven Le Corre (1) , Jean-Luc Bailleul (1) , Arthur Lévy (1)

1 LTeN - Laboratoire de Thermique et d’Energie de Nantes
2 Sabanci University - Faculty of Engineering and Natural Sciences

The evolution of polymer welding time to join the interface of thermoplastic Polyetherketoneketone (PEKK) matrix composites was characterized. Using a creep-recovery test protocol to analyse the evolution of rheological behavior, it was shown that for temperatures above the melting point (T > 360 o C), the polymer visco-elastic relaxation time increases exponentially with time-indicating polymer crosslinking or branching. To confirm that relaxation time is proportional to interface healing time, the rheological results were compared to the fracture energy release rate (G 1c) of samples prepared on a custom bench which is capable of isothermally weld composite samples for controlled time intervals. The welding time corresponds directly to the relaxation time. Furthermore, the thermal history that the polymer experienced results in cross linking and influences the welding time. The implication is that temperature exposure from prior processing steps (IR oven pre-heating or autoclave consolidation) can limit the ability to weld components in a predictable way.

Mots clés: A. Thermoplastic resin; B. Adhesion; D. Rheology; E

Domaines: Thermique [physics.class-ph]

Julien Avenet, Thomas A Cender, Steven Le Corre, Jean-Luc Bailleul, Arthur Lévy. Experimental correlation of rheological relaxation and interface healing times in welding thermoplastic PEKK composites. Composites Part A: Applied Science and Manufacturing, 2021, 149, pp.106489. ⟨10.1016/j.compositesa.2021.106489⟩. ⟨hal-03266220⟩