3. Problems posed by additives and fillers

In some cases, separating the polymer from its additives is either unnecessary (e.g. when analyzing a polymer in the presence of 0.5% antioxidant), or impossible (e.g. when analyzing three-dimensional filled polymers).

In other cases, however, separation is necessary: either because the adjuvant in high concentration masks much of the information about the polymer, or because a study of the additive itself is impossible in a polymer matrix (e.g. analysis of a mixture of antioxidants).

Separation is generally based on the difference in solubility between polymer and adjuvant. Different methods can be used.

• Re-precipitation: the material is put into solution; the solution is gradually added to a large volume of non-solvent kept under stirring. If the solvent-non-solvent pair is chosen appropriately,...