Mechanics of adhesive failure. I

TLDR

The intrinsic interfacial energy governing adhesive failure depends on the surface properties and compositions of the joint materials. Adhesive failure energy was measured over a wide range of temperatures and crack propagation rates for model joints between cross‑linked rubber and rigid polymeric substrates. The measured failure energy decomposes into a viscoelastic component proportional to the intrinsic interfacial energy and an intrinsic component, producing a master curve via the WLF equation; the intrinsic energy agrees with the thermodynamic work of adhesion in pure interfacial failure.

Abstract

The mechanics of adhesive failure have been investigated by using model adhesive joints between a cross-linked amorphous rubber and rigid polymeric substrates. The adhesive failure energy, 0 , was determined over a wide range of temperatures and rates of crack propagation. For any given rubber-substrate joint the results yield a single m aster curve w hen reduced to a reference temperature by means of the Williams-Landel-Ferry equation. It is shown that 6 is the sum of two components: the energy dissipated viscoelastically within the rubber at the crack tip and the ‘intrinsic ’ adhesive failure energy 0 0 . The value of the former is proportional to 0 0 , so that 0 can also be represented as the product of 0 0 and a function of rate and temperature. The prameter 0 0 is governed by the surface properties and compositions of the materials forming the joint. When pure interfacial failure occurs, 0 0 has a value in close agreement with the thermodynamic ‘work of ad hesion’ determined independently.