Adhesives for Low-Energy Surfaces

The wetting and adhesive properties of model pressure-sensitive adhesives synthesised by miniemulsion polymerization were investigated. Wetting experiments of aqueous solutions of three different emulsifiers showed that Silwet L-77 (nonionic ethoxylated trisiloxane) was the best wetting agent. Probing adhesive properties, two different structure modifications of the polymer were investigated: a change in the polymer microstructure by the addition of a chain transfer agent and the introduction of a hydrophobic monomer into the polymer backbone. An addition of chain transfer agent was sufficient to obtain a polymer with a significantly different microstructure and, consequently, enhanced adhesion energy but reduced shear resistance. On the other hand, stearyl acrylate (SA) was employed as the hydrophobic monomer and the synthesis was carried out in miniemulsion polymerization which enables the incorporation of hydrophobic compounds without any diffusion limitations. There were almost no differences in the polymer microstructure, whereas, some differences were observed in adhesion properties.