Temperature Dependence of Peeling Strength of Polyisobutylene

Abstract

The analytical method for obtaining the relation between the peeling rate and the peeling strength has recently been reported by using the numerical solution of peeling stress distribution. It has been experimentally known that the relation changes with temperature at which it was peeled. This paper presents the data for temperature dependence of peeling strength of polyisobutylene (PIB) at temperature far above its glass transition.The analysis of the relation between the peeling rate and the peeling strength showed that our theoretical estimation predicts the data fairy well at temperatures lower than 20°C, but the coincidence is not so good at temperatures higher than 50°C. From the analysis of the relation, three essential parameters are derived. They are P0, the constant peeling strength at lower peeling rate, P∞, the constant peeling strength at higher peeling rate and τ, the relaxation time of the three element viscoelastic model which is assumed to show the mechanical property of adhesive interlayer.The temperature dependence of τ are similar to that of aT for PIB and they agree with WLF equation except for PIB-PTFE (polytetrafluoroethylene) system. But the value of the constants differs from the value of their equation. The temperature dependence of τ for PIB-PVC (polyvinyl chloride) system shows an abrupt change at a temperature between 70°C and 90°C. The temperature dependence of P0 and P∞ also changes abruptly at the corresponding temperature. It may be considered that the property of adhesive interlayer changes at the temperature and that the change is accounted for by the glass transition of PVC. The temperature dependence of τ for PIB-PTFE system also seems to reflect the rheological properties of PTFE.The mechanical property of adhesive interlayer may be determined by the mechanical properties of both the materials forming the interlayer.