Adhesive Bonding Lap Shear Strength Improvement of Cfr(peek) Laminates by Surface Morphology Modifications

In this paper, an experimental study concerning the effect of surface morphology on mechanical properties of adhesive bonding behaviour of continuous carbon fibres reinforced PEEK was performed. Surface morphology of PEEK composite was varied by sandblasting process. 3D morphological parameters were calculated from interferometry measurements. Surface wettability behaviour was studied by deposed sessile drop technique and the contact angle between solid surface and liquid was measured. Thus, a correlation between surface morphology and contact angle variation was discussed. Adhesive bonding strength of system PEEK/Epoxy/PEEK was measured by standardised single lap shear test. A correlation between surface morphology and adhesive bonding strength was investigated. The pertinent morphological parameters issued from a special surface filtering linked to adhesive bonding strength were determined. 1 General introduction Continuous carbon fibre reinforced polymers composites have successfully replaced aluminium alloys in many aeronautic parts due to their improved lightweight, fatigue and chemical resistance. These parts must be joined together. Nowadays, several techniques are used in structural joining of these materials: adhesive bonding, bolting, riveting and welding. The adhesive bonding technique is an ideal process for assembling structural composites parts. Indeed, this method offers many advantages such an uniform stress distribution along the joint, no reduction in the strength due to notch sensitivity of composite materials, weight and cost reduction, compared with other joining techniques like bolting, riveting or welding. PolyEtherEtherKetone PEEK is a high performance semi-crystalline thermoplastic. PEEK based composites are increasingly used in aeronautical industry due to their improved impact behavior and their recycling potentials compared to thermosetting polymers. However, high performance of these materials results in a good chemical resistance and hence their surface interactions with environmental elements are difficult. Consequently, surface preparation and treatment of PEEK composites are necessary to improve the adhesive bonding strength [1]. Currently, several techniques of surface preparation for adhesive bonding are used. These methods can be classified in three main groups: mechanical treatments like paper abrasion and sandblasting, physical treatments as plasma and laser treatments and finally chemical treatments like solvent degreasing and chemical etching [2]. Low cost, environmental friendly and easy to implement method make sandblasting treatment one of competitive methods for preparing thermoplastic material surfaces before adhesive bonding [3]. The relationship between surface texture and adhesion is complex. In the purpose to optimise abrasive surface treatment processes, different mechanisms and their interactions need to be understood [4, 7]. Moreover, the adhesive bonding ADHESIVE BONDING LAP SHEAR STRENGTH IMPROVEMENT OF CFR(PEEK) LAMINATES BY SURFACE MORPHOLOGY MODIFICATIONS R. Ourahmoune, M. Salvia, N. Mesrati, T. G. Mathia 1 Laboratoire de Tribologie et Dynamique des Systèmes, Ecole Centrale de Lyon, Lyon, France, 2 Laboratoire Sciences et Génie des Matériaux, Ecole Nationale Polytechnique, Algiers, Algeria * Corresponding author ([email protected])