7. Solubility and transport of antioxidants in polymers

For an additive molecule to have stabilizing properties, it must, of course, carry the functions described above. This is a necessary but not sufficient condition, as the molecule must also be soluble in the polymer, and its concentration must reach a sufficient level for the stabilizing effect to be fully manifested. As it happens, many of the most industrially important polymers (polyolefins, hydrocarbon elastomers) are not very polar and therefore not very compatible with moderately or highly polar molecules, which is the case for most small molecules carrying only the antioxidant function. Solubility problems in polymers can therefore be critical and require detailed investigation