THE TGA-FTIR-GC/MS CHARACTERIZATIONS OF PYROLYSIS OF POLYURETHANE PAINT SLAGS

Hazardous paint waste from industrial production is an ever-growing concern due to its toxicity and flammability effect. Currently, pyrolysis is one of the promising technologies for paint waste disposal because of its ability to minimize and disinfect waste together with energy recovery. In this study, characterization of pyrolysis of polyurethane paint slags was conducted using TGA-FTIR-GC/MS, and the evolved products were analyzed. The effect of heating rate (10 °C per minute, 20 °C per minute, and 30 °C per minute) were assessed. The TGA results showed that two stages involved in the pyrolysis of waterborne polyurethane paint slag. The first stage was 200~325 °C, while the second stage involved the intense weight loss at 330~500 °C. In addition, the thermal pyrolysis of oily polyurethane included four stages during the pyrolysis reaction. The first three stages were 200~300 °C, 300~435 °C, and 435~640 °C, respectively, which correspond to the volatiles and the decomposition reaction of some organic matter. The fourth stage was the pyrolysis of fixed carbon at 640~790 °C. The increase of heating rate can improve the pyrolysis intensity of two polyurethane paint slags. The FTIR results showed that a large amount of CH4, CO2, CO, H2O, alkanes, olefins, and aromatic compounds were emitted during the pyrolysis of the two paint slags. The GC/MS results concluded that the pyrolysis products of waterborne paint slag were mainly HC and O-compounds, and the pyrolysis products of oily paint slag also included N-compounds. This study provides a theoretical reference for the pyrolysis characteristics and product properties of polyurethane paint slags.