Comparison of the activation energies as determined by DSC and by conventional methods

The results of determination of activation energies (E-A) of polymeric cabl e insulations obtained by conventional methods (usually based on the evalua tion of changes of mechanical properties of insulations after their ageing in thermal chamber at different temperatures) have been compared with resul ts obtained by methods employing the differential scanning calorimetry (DSC ). Three DSC methods have been tested: the method according the ASTM E 698; measuring of DSC characteristics in the isothermal mode at several differe nt temperatures; and the method based on evaluation of DSC characteristics of insulations after their thermal ageing in thermal chamber. The last meth od - which can be called as a modified conventional method, because instead of mechanical properties, the DSC characteristics are determined - has bee n found as most acceptable and giving similar values of E-A as the other co nventional methods.