Wool/Polymer Interactions: Part II : Measurement of Adhesion Between Single Wool Fibers and a Polyurethane Elastomerl

Two methods were investigated for measuring the adhesion between single Lincoln fibers and a polyurethane elastomer. The importance of viscoelastic properties on the measured adhesive force was shown at low speeds of testing where the wool/polymer adhesive force increased with speed, parallel to the tearing energy of the elastomer. Estimates of the surface component of adhesion, θ0, were consistent with the conclusion that θ0» W0, where Wo is the calculated wool/polymer thermodynamic work of adhesion, assuming only van der Waals' bonding across the interface. Covalent bonding at the wool/polymer interface and/or me chanical interlocking of polymer under the scale edges could account for the large values of θ 0 as well as the mixed-mode (i.e. interfacial and cohesive) failure observed from scanning-electron-microscope studies.