Fuente: Polymers Polymers, Vol. 18, Pages 1381: Advanced Analytical Framework for Pyrolysis Product Characterization and Emission Profiling in Mixed Plastic Waste: Implications for Recycling Strategy
Polymers doi: 10.3390/polym18111381
Authors:
Aiping Chen
Saumitra Saxena
Vasileios G. Samaras
Bassam Dally

Chemical recycling of mixed plastic waste can recover hydrocarbon products, but additive-derived non-intentionally added substances (NIASs) and other volatile or extractable residues may affect product quality and safety. In this study, six polyolefin-rich waste streams (P1–P6) were analyzed by analytical pyrolysis coupled with comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (Py–GC×GC–TOF–MS), while three additional consumer-grade plastics (P7–P9) were examined by headspace/solvent-extraction GC–MS and aqueous migration testing to profile volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), and water migrants. Under rapid pyrolysis at 650 °C, the condensable products were dominated by C5–C30 aliphatic hydrocarbons. Polyethylene (PE)-rich feeds produced mainly n-paraffins and α-olefins, whereas polypropylene (PP)-rich feeds produced more branched olefins and modest mono-aromatics. Oxygenated compounds were negligible in non-oxidized feeds, but persisted at low levels in weathered high-density polyethylene (HDPE), consistent with pre-existing oxidation. Antioxidant-derived NIASs, including 2,4-di-tert-butylphenol and an Irganox 1010-related spiro-dione, were detected at trace to low area-fraction levels. VOC/SVOC and migration analyses revealed mainly low-intensity hydrocarbons, esters, antioxidant-related degradation products, caprolactam, and selected plasticizer-related compounds. These results show that relatively clean polyolefin streams can yield hydrocarbon-rich pyrolysates, but oxidized PE and additive-derived NIASs remain important quality-control targets. The GC-based methods used here characterize the volatile, condensable, and readily extractable fraction and do not represent the total contaminant load of the source waste.