ABSTRACT
Pressure-sensitive adhesives (PSA) are viscoelastic materials with flow properties playing a key role in the bond forming the elasticity plays a key role in the storage of energy. The stress rate-dependent stiffening is an increase in the elastic contribution to the rheology of the polymer. When the elastic components are predominant more of the bond rupture energy is stored, resulting in higher peel and tack properties. PSAs are polymers containing long-chain entangled molecules with intra-and intermolecular mobility. At low strain rates, the viscous components of the polymer dissipate energy, and as a result resistance to debonding forces is low. Nonlinear viscoelastic behavior results in additional stored energy, and the debonding resistance intensifies accordingly. The end-use properties of PSAs result from the nonlinear viscoelastic behavior of the adhesive material, and the elastomeric polymer basis of PSAs imparts them such a viscoelastic behavior.
