Viscoelastic behaviour of water-based pressure sensitive adhesives (PSAs)

Water-based pressure sensitive adhesives (PSA) obtained by emulsion polymerization have peculiar characteristics compared with their solvent counterparts. In particular they contain significant amounts of microgels, permeated by uncrosslinked molecules, and generate micronetworks after film formation. Viscoelastic characterization of three PSAs, both in the linear limit and in uni-axial elongation is reported in this paper. Modeling of tensile stress-strain curves is proposed, based on a network theory accounting for the presence of entanglements (Ball et al. Polymer, 1981, 22, 1010-1018). A rate-dependence of some of the physical parameters of the model is introduced in order to describe experimental data.