Effects of 2H-heptafluoropropane on the liquid and tar products of poly(methylmethacrylate) flash pyrolysis

The flash pyrolysis of poly(methylmethacrylate) (PMMA) granules in nitrogen and 2H-heptafluoropropane (HFP) atmosphere were carried out in a tube-type pyrolyzer at 700 °C, respectively. The liquid and tar products were transported by the continuous flowing environmental gases, and collected by Cambridge pad. The products were detected and identified by gas chromatography combined with mass spectrometry (GC/MS). The results indicate that the liquid and tar products mainly consist of some aromatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs), and the distributions of pyrolysis products in HFP atmosphere are rather different from that in nitrogen atmosphere. The presence of HFP results in an obvious concentration decrease of most oxygenated aromatic compounds, as well as an increase of almost all the aromatic hydrocarbons. The mechanisms of the changes are discussed from the aspect of reaction pathways.