Relationship between viscoelastic and peeling properties of model adhesives. Part 2. The interfacial fracture domains

The viscoelastic and peeling properties of polybutadiene/tackifying resin c ompatible blends have been studied in detail. Viscoelastic properties have been described through the variations of the complex shear modulus, G*(omeg a), as a function of frequency, omega, and peeling properties through the v ariations of peeling force (F) as a function of peeling rate (V). The first paper of this series presented the cohesive fracture domain and t he present paper explores the interfacial fracture domain: (i) rubbery inte rfacial (interfacial i).; (ii) stick-slip; (iii) glassy interfacial (interf acial 2). After a general survey of the properties in the three domains we present a quantitative relationship between the peeling anti linear viscoel astic properties as a function of the adhesive formulation, discussing the use of time-temperature equivalence for adhesive properties. The third part of the paper presents the trumpet model of de Gennes describing the crack shape and propagation: starting from a mechanical analysis of the peeling t est, it is shown how one may calculate the variations of the peeling force as a function of peeling rate in the various interfacial fracture domains: this model defines a single interfacial fracture criterion which coexists w ith the cohesive fracture criterion defined earlier, whatever the fracture location. We present as a conclusion a critical discussion of the relevance and physi cal meaning of such a criterion and present a new outlook for the modeling and improvement of adhesive formulations.