Surface Characterization of Arylic Acid Content in Pressure Sensitive Adhesives
Senior Scientist, KRÜSS
February 24, 2021 | 11:55 AM to 12:20 PM ET
In the automotive and aeronautical industries, the use of composite materials as an alternative to metals is constantly explored owing to the lightweight, strength, durability, and long-term stability of these materials. Bonding to these surfaces, however, is a challenge due to their low surface free energies where peeling and delamination problems are often observed. The use of pressure sensitive adhesives (PSA) as bonding material has been widely explored owing to the ease of use and high strength of these materials and these materials are constantly being developed to enhance their adhesive properties. Herein, we explored the correlation between the concentration of the acrylic acid and the surface polarity of the PSA surface, which is important for the development of these materials and the optimization of the PSA surface that will be bonded with a substrate of interest. In this study, we used both the sessile drop and the tensiometric based methods to look at the wetting behavior of these surface and determine the polarity of the PSA surface with respect acrylic acid concentration. We will show that while the sessile drop method is excellent in determining the wettability of water on the PSA surface, no clear distinction can be deduced on its correlation with acrylic acid concentration due to polymer side chain orientation. On the other hand, using dynamic contact angles method, a clear correlation can be seen between the effect on surface polarity of the PSA surface with acrylic acid content. With increasing acrylic acid concentration, a decrease in water contact angles was observed.