Temperature and contact pressure effects on the adhesion development of high performance thermoplastic composites

Julien Avenet (1) , Steven Le Corre (1) , J-L. Bailleul (1) , Arthur Lévy (1)

1 LTeN - Laboratoire de Thermique et d’Energie de Nantes

Thermoplastic composites offer new manufacturing prospects, thanks to the ability to melt the matrix. Welding, tape placement, 3D printing, overmoulding, or even stamping involve adhesion of the thermoplastic polymer at high temperature. First, under heat and pressure, contact at the microscopic scale is ensured by the deformation of surface roughness, this is the intimate contact step. Then, the development of the mechanical strength of the assembly is controlled by the diffusion of macromolecules at the interface which is defined as the healing step. Nowadays, continuous manufacturing processes tend to be faster and present very short residence time which could limit the adhesion development. A good understanding of these mechanisms is therefore very important to control and predict such industrial processes. Welding tests at different temperatures and contact pressures were carried out over a large range of residence times using a controlled welding bench enabling very short welding times (down to 1 second). The mechanical adhesion between PEKK-carbon composite samples was characterized using double cantilever beam fracture tests. Adhesion was found to develop in two steps which could be described as an intimate contact-healing coupled step and a pure healing step. From this, the healing kinetics was identified and an empirical model was developed to account for the effect of pressure on adhesion build-up. This model could then be compared with existing models to describe the establishment of intimate contact between the coupons.

Mots clés: Adhesion; Thermoplastic Composites; Intimate contact; Healing

Domaines: Thermique [physics.class-ph]

Julien Avenet, Steven Le Corre, J-L. Bailleul, Arthur Lévy. Temperature and contact pressure effects on the adhesion development of high performance thermoplastic composites. 24th International Conference on Material Forming (ESAFORM 2021), Univsersité de Liège, Apr 2021, Liège, France. ⟨hal-03203961⟩