Material recycling of plastics waste for demanding applications: Upgrading by restabilization and compatibilization

Recycled plastics suffer from chemical damage that occurs during processing and first-life application. New functional groups formed enhance the sensitivity of the recyclate to thermal- and photo-degradation. The characteristics and properties of structural inhomogeneities (polymeric impurities) formed in the polymer during processing and ageing, and of nonpolymeric impurities admixed or generated during the first lifetime of the plastic, are of great importance. With the formation of new pro-oxidative functional moieties, as substantial part of the stabilizers added for the first lifetime are simultaneously consumed. As a consequence, the mechanical properties of commingled plastic recyclates generally do not meet material expectations. Increase in resistance to degradation, by proper restabilization, and the recovery of physical properties, by compatibilizers, represent the state-of-the-art in the material recycling of plastics for demanding applications.