Surface Laser Micropatterning of Polyethylene Terephthalate (PET) to Increase the Shearing Strength of Adhesive Joints

Abstract

Abstract. The method for increasing the shearing strength of adhesive joints in plastics was investigated. This method uses laser micropatterning of different construction materials to extend adhesive surfaces. In investigations, Polyethylene Terephthalate (PET) was used. TruMicro 5325c ultra-short pulse (picosecond pulse) laser and the SCANLAB GALVO scanning head applied in the research enable ablative removal of the material without the heat-affected zone (HAZ) in the rest of it. Ultra-short laser pulses (such as picosecond pulses) remove material without melting the rest of it. The presented method significantly increases the shearing strength of the formed joints in investigated materials made from plastics, which was proved in the results of laboratory tests. The laser device parameters used, which are described in this article, have not produced cracks in the microtreated materials. The research shows that bondings between elements with the appropriately machined microstructure are characterized by a severalfold increase in the strength of joints in relation to materials devoid of the microstructure. In addition, this study addresses practical solutions to the adhesive method used for joining of the polymers used for tests. This study could be helpful for each application where we have to connect these types of polymers.