Plastic waste causes major problems for the environment worldwide. Chemical recycling via thermal or plasma catalytic pyrolysis has not been adopted as major strategy due to the complexity of the process, high costs, or low economic revenue from energetic valorisation via products like H2 or syngas. Herein, a plasma pyrolytic recycling process is presented which allows for the direct conversion of common plastic waste into valuable chemical feedstock gas. The capacitively coupled RF plasma at 13.56 MHz and a power below 50 W is operated with pure Argon at 1 bar or higher, while the plasma device stays below 80 °C. The plasma process was characterised for samples of polypropylene (PP), polyethylene (PE), polystyrene (PS) and polyethylene terephthalate (PET), which constitute most of the common household waste. The output gas composition was analysed by FTIR and mass spectroscopy. Residues of graphite powder were analysed by scanning electron microscopy, EDX and XRD. Besides hydrogen, the plasmolysis of PP yields more than 2/3 of acetylene, ethylene and propylene of the volatile fraction, while the plasmolysis of PET containing 18%mol of oxygen yields output gases with a dominating fraction of CO and CO2. Thus, the described process may have the potential to improve the economic viability of direct chemical recycling for plastic waste while reducing the need to use fossil fuels as raw products for the generation of chemical feedstock gases.
