Rheological, Interfacial and Thermal Control of Polymer Adhesion. I. Isothermal Theoryf

We have developed an isothermal theory of separation in polymer-solid adhering systems. The model used is based on the (observed) drawing of filaments between a bulk polymer and a solid. In the isothermal theory, a criterion is set up, demarcating filament elongation vs. detachment of the filament base from the solid. It employs a dimensionless parameter, ω, that relates free energy of adhesion, elongational viscosity or yield strength of the polymer, and filament size, to adhesive performance. The isothermal theory can be applied directly to the separation processes that occur with pressure-sensitive adhesives. Certain observations by Aubrey and Sherriff, by Gardon and by Kaelble are explained. The validity of the demarcation is believed to extend beyond pressure-sensitive systems, to all thermoplastic adhesives and/or coatings.