On the use of oxidative stability measurements for short-term thermal endurance characterization of polymeric materials

A rapid procedure for thermal lifetime prediction of polymeric materials consisting of the evaluation of the activation energy from isothermal thermal analysis data and the determination of an isotherm of thermal degradation corresponding to the maximum permitted temperature for accelerating aging is discussed. The methods of evaluation of the activation energy from isothermal thermal analysis data [differential thermal analysis (DTA), differential scanning calorimetry (DSC) and chemiluminescence (CL)] are critically analyzed. It is shown that large differences between the activation energy values evaluated by conventional procedure given in IEC 216 Standard and by analytical methods, cause large errors in the thermal lifetime prediction using the rapid method, although the differences between temperature index (TI) values evaluated by both procedures of thermal endurance characterization are small. (C) 2000 Elsevier Science Ltd. All rights reserved.