Thermal stability of polyethylene terephthalate food contact materials: formation of volatiles from retail samples and implications for recycling

PET packaging materials have been tested for volatile content after exposure to high temperatures. Samples included laminates, bottles, and roasting bags, and were heated at 120 degrees C, 150 degrees C and 230 degrees C for 50 min, according to sample type. Volatiles released from the material were trapped on Tenax, identified by GC-MS and assessed against a 10 mu g/kg migration threshold limit. Few volatiles were found for samples composed only of PET. Volatiles from laminates varied according to the sample structure, but the main substances identified were not related to PET, but probably came from printing inks and adhesives. It is concluded that the migration potential of PET in high temperature applications is very low and that the formation of volatiles during use is unlikely to cause any special problems in polymer recovery in recycling schemes, provided that other packaging residues are removed effectively.