Surface Preparation Techniques for Adhesion to Aerospace Thermoplastic Composites
Thermoplastic composite materials are an attractive alternative to thermoset composites due to their high strength, simplified processing, and lower cost of manufacturing. As the interest in implementation of thermoplastic composites increases, so does the need for robust surface preparation methods for finishes, e.g., primers, paints, and sealants. The technical development of thermoplastic composite materials and processing has outpaced the development of methods to enable excellent adhesion of finishes to thermoplastic composites. The development of robust surface preparation techniques for improved adhesion has become an enabling technology for the widespread implementation of thermoplastic composite parts. Several surface preparation techniques, including sanding, grit blasting, chemical treatment, plasma treatment, and laser ablation, were considered as methods of surface preparation for finishes on carbon fiber reinforced polyether ketone ketone (PEKK) thermoplastic composite parts. The surface characteristics of the treated coupons were analyzed and adhesion to common aerospace primers and sealants was tested. Comparisons were made to develop an understanding of how each surface preparation technique affects the chemistry, microstructure, and surface energy of the surface, and how those surface changes affect the adhesion of subsequent finishes. The adhesion results for common aerospace primers and sealants provide empirical evidence for the implementation of certain techniques.
Authors: Karen A. Schultz, and Angela C. Davis
Conference: SAMPE Seattle 2017