Specimen preparation: respecting the specific characteristics of the polymers to be tested

Plastics are a special class of materials in competition with metals, among others. Their properties differ markedly from those of metals. The deeply-rooted technical culture of metallic materials needs to be adapted to take account of the differences in behavior when preparing test specimens.

Motivations and characterization methods are too diverse to lay down universal rules, but characterization managers and operators must always bear in mind the specific features of plastics to avoid the many pitfalls:

• Plastics melt or are sensitive to lower temperatures than metals. Thermal degradation can begin at temperatures of just a few tens of degrees;

• the macromolecular organic structure gives rise to viscoelastic behaviour leading to specific thermomechanical properties;

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