Structural and dynamic characterization by 1H NMR and FT-IR analyses of oils obtained by low temperature slow pyrolysis of waste plastics

Abstract The present study explores the transformation of waste packaging plastics high-density polyethylene (HDPE), polypropylene (PP), and polystyrene into combustible condensates through slow pyrolysis at low temperatures, using a custom-built reactor inspired by the Blest machine model. To characterize their structural properties, the original plastic materials, their pyrolysis derivatives, and three conventional liquid fossil fuels were examined using advanced techniques, including 1 H relaxometry, double quantum nuclear magnetic resonance, and Fourier Transform Infrared spectroscopy. The resulting condensate oils, collected unfiltered, exhibited clear amber shades and demonstrated partially Newtonian fluid behavior. A comparative analysis of their calorific values with traditional fossil fuels revealed that HDPE and PS-derived oils possess viable fuel properties, although the production process remains costly.