scope:

According to the procedure recommended in VDI 3822, instrumental analysis plays an essential role in conducting a successful failure analysis of a plastic product. The failure analyst must be able to identify the appropriate analysis methods for the questions he poses and also be familiar with their potential for solving the problem. He must be able to assess what type of findings that can be expected from a given method in the specific case of failure to be investigated, or which method will allow a desired conclusion to be drawn.

In the following, methods that are often used in failure analyses of plastic products will be presented, along with the abbreviations used for them in the other parts. Subsequently, their functional principles will be briefly explained and examples of the properties that they can be used to characterise will be provided. In addition, examples of their use in failure analysis will be cited.¹⁾ However, information on the underlying failure mechanisms is to be found in the corresponding parts.

The following tables in Section 3 organise the analysis methods into the following categories:

1) microscopic procedures

2) thermal analysis methods

3) spectroscopic methods

4) rheometric/viscometric methods

5) chromatographic methods

6) mechanical testing methods

7) other methods

It should be kept in mind that a combination of appropriate methods is generally of primary importance for significant results. Whether a method is applied or not, depends upon the framework conditions of the individual case, namely, which question is to be answered, which sample qualities²⁾ are required and which are available. Furthermore, the resulting costs, both in terms of time and money, also play a decisive role.

¹⁾ Die Angaben in den Tabellen sind beispielhaft und erheben nicht den Anspruch auf Vollständigkeit. / The information in the tables is only exemplary and does not claim to be exhaustive.

²⁾ Damit ist beispielsweise gemeint, dass die Ermittlung mechanischer Werkstoffkennwerte wie die Bruchdehnung nur anhand von Prüfkörpern möglich ist. Das vorhandene Schadensprodukt und die Referenzprodukte müssen die Entnahme von derartigen Proben erlauben. / This, for example, means that the determination of the mechanical characteristics of a material, such as bending fracture strength, is only possible by using reference pieces. The defective product at hand, and the reference products, must allow for the collection of such samples.