pH Dependence of the Properties of Waterborne Pressure-Sensitive Adhesives Containing Acrylic Acid

Abstract

Polymer colloids are often copolymerized with acrylic acid monomers in order to impart colloidal stability. Here, the effects of the pH on the nanoscale and macroscopic adhesive properties of waterborne poly(butyl acrylate-co-acrylic acid) films are reported. In films cast from acidic colloidal dispersions, hydrogen bonding between carboxylic acid groups dominates the particle-particle interactions, whereas ionic dipolar interactions are dominant in films cast from basic dispersions. Force spectroscopy using an atomic force microscope and macroscale mechanical measurements show that latex films with hydrogen-bonding interactions have lower elastic moduli and are more deformable. They yield higher adhesion energies. On the other hand, in basic latex, ionic dipolar interactions increase the moduli of the dried films. These materials are stiffer and less deformable and, consequently, exhibit lower adhesion energies. The rate of water loss from acidic latex is slower, perhaps because of hydrogen bonding with the water. Therefore, although acid latex offers greater adhesion, there is a limitation in the film formation.

Waterborne Polyurethane−Acrylic Hybrid Nanoparticles by Miniemulsion Polymerization: Applications in Pressure-Sensitive Adhesives

“…Force spectroscopy experiments on individual latex particles 39 and adhesive films 16,[40][41][42][43][44][45] to determine their nanomechanical properties have already been reported elsewhere. between the surface and the AFM tip was calculated by subtracting the deflection of the cantilever, z, from the height values that corresponded to the measured piezoelectric displacement, z piezo :…”

Near-Surface Composition Profiles and the Adhesive Properties of Statistical Copolymer Films Being Model Systems of Pressure Sensitive Adhesive Films

“…By applying a slight pressure, a releasable bond to the substrate is formed (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11). In many PSA applications, a controlled release of the adhesive bond is desired, making use of the ability to undergo several cycles of bonding and detaching.…”

Water-based acrylic coatings reinforced by PISA-derived fibers

“…The comparison of the reference films formed at pH 5.5 or 12, in Figure 2, shows that the film made at pH 12 was much stiffer, in the medium strain region, and more extensible, while maintaining a similar Young's modulus as the film formed at pH 5.5. The observed stiffening through pH increase is a known phenomenon in acrylic acid (AA) containing formulations 7,20 and it is usually explained by the formation of long lived ionic clusters. It must therefore be taken into account in the interpretation of the films incorporating the glassy additives.…”