AN ULTRASENSITIVE TECHNIQUE FOR TESTING THE ARRHENIUS EXTRAPOLATION ASSUMPTION FOR THERMALLY AGED ELASTOMERS

We present a general approach for more confidently correlating acceler ated aging results with aging under service conditions using the Arrhe nius methodology. We first show that, as a result of complex diffusion -limited oxidation effects, time/temperature correlations may occur fo r some properties but not for others. To rigorously extrapolate high t emperature results to low temperatures, we sought an ultrasensitive te chnique correlated to macroscopic degradation and capable of measureme nts at or near service temperatures. We achieved this objective by mon itoring oxygen consumption rates at high (accelerated) temperatures, t o establish the necessary correlation, and at low temperatures (down t o 23 degrees C), to determine their temperature-dependence in the extr apolation region. Because easily measurable oxygen consumption rates o f 10(-13) mol/g s correspond to decades of predicted lifetime for most elastomers, this approach increases confidence in long-term predictio ns and therefore provides a means of testing Arrhenius extrapolations.