Changes in the Dynamic Modulus during Thermal Degradation of Polyisoprene Vulcanizates

Abstract

Abstract Thermal degradation of IR is investigated in air and in N2 by dynamic mechanical measurements. In this dynamic method, the change in the relative dynamic modulus is found to be frequency dependent, but the data at various frequencies can be superimposed upon each other by shifting along the time axis. Changes in relative modulus as a function of time in air and in N2 can be expressed by Equation (1), which contains two exponential terms. The activation energies for k1 and k2 are 84 and 57 kj/mol in air, and 61 and 57 kJ/mol in N2, respectively.