Transfer phenomena of volatile organic compounds in thermoplastic polymersand polymer blends by supercritical carbon dioxide

The low-temperature uptake of the flavouring agents limonene and vanillin f rom supercritical carbon dioxide (CO2SCF) into films of a poly(ethylene ter ephthalate)-based copolyester (PET-G), polycaprolactam (PA6), and isotactic poly(propylene) (PP), also blended with hydrogenated oligo(cyclopentadiene ) or polycaprolactam, have been investigated through thermogravimetric dete rmination of the additive amount released in the temperature range 30-230 d egrees C. The uptake of an additive strongly depends on its relative solubi lity in the polymer and in CO2SCF: limonene can easily be transferred into lipophilic PP-based and PET-G polymers, also due to the plastifying action of CO2SCF on PET-G, while only the more polar vanillin can be taken up by h ydrophilic PA6. The CO2SCF treatment is particularly suitable for the low-t emperature uptake of heat-sensitive flavours into polymeric substrates to b e used in "active" packaging.