Lifetime prediction, oxidation methods

Figure 1. Schematic representation of the method to predict lifetime ofpipes from oxidation induction time (OIT) data. Drawn after a chart presented in Viebke and Gedde, (10).

A common method of predicting product lifetimes assumes a single, thermally activated degradation process, with rate given by Eq. (11.8). If failure occurs when oxidation or hydrolysis reaches a critical level, the failure time is given by... 

Cyclic oxidation testing is a key method to aid material selection and to predict service lifetime of components. However, it is a complex procedure that has many possible variables. Hence it is often difficult to compare data from different laboratories unless either (i) the procedures in each laboratory are similar, or (ii) the influence of any differences in procedure on the resultant data is known. 

The main aim has to be that this test can predict lifetime of plastic products under complex conditions (e.g. heat, oxidation, chemicals and mechanical loading) within a short test time in the laboratory. We agree with the discusser that such a test wll be a more economical and quicker method than the current method. 

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