Rate dependent shear debonding between a highly stretchable elastomer and a rigid substrate: Delayed debonding and pre-stretch effect

Abstract

In this paper, the interfacial shear debonding characteristics and mechanism between a highly stretchable acrylic tape and a rigid polycarbonate strip are explored systematically with three types of in-plane loading. An effective approach is proposed based on the findings to improve interfacial adhesive strength. The debonding energy solely dissipated by breaking the interfacial bonds is found to be closely related to the loading rate, which can be explained by the Chaudhury’s model. Rate dependent delayed debonding is repeatedly observed under various stretch levels. The threshold level of the driving force of delayed debonding is correlated with the intrinsic fracture energy of the interfacial molecular chains and expected to be rate independent. Shear debonding is significantly affected by the pre-existed defects at the interfacial crack front. An effective and easy-to-operate cyclic pre-stretch approach with a moderate amplitude and rate is proposed, which is capable of improving the interfacial reliability by diminishing the pre-existed defects. A quantitative model is also constructed to characterize the pre-stretch effect on the interfacial adhesion.