Voc Emissions from Waste Plastics during Melting Processes

Hazardous compounds emitted during the plastic melting process were analyzed to indicate potential air pollution issues associated with recycle plants for waste plastics. These hazardous compounds might be not only from polymer degradation but also from additives and print ink. To confirm what are emitted from them, melting experiments were conducted (150, 200 and 250°C, in air or N2) and volatile organic compounds (VOCs) emitted from samples were trapped by Tenax/Carboxen adsorption tubes and analyzed by TD-GC/MS. In the present study, virgin polymers such as low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS) and reproduced plastic were tested. As a result, higher temperature caused more emission of VOCs. Moreover, less VOCs and less oxygenated organic compounds which were said to be hazardous to human and the cause of bad odor were emitted in N2 atmosphere than in air. Based on these results, lower temperature and lower oxygen level are preferable to reduce hazardous compounds during the plastic melting process of mechanical recycling.