Identification of Biodegradable Plastics by Pyrolysis-Gas Chromatography-Mass Spectrometry

Biodegradable platics were mainly identified by the method of compost degradation to determine their biodegradability, which had long detection cycle and high cost. The composition of the material basically determined its biodegradation characteristics. In order to identify quickly biodegradable materials, the pyrolysis characteristics of mixed samples of poly(butylene adipate-co-butylene terephthalate) (PBAT) and other components at different mass ratios, including biodegradable polylactic acid (PLA), and non-biodegradable material polystyrene (PS) or polyethylene terephthalate (PET), were studied by pyrolysis-gas chromatography-mass spectrometry (PY-GC-MS). As shown by the results, the characteristic peak of PBAT decomposition was obvious and was not affected by PLA. If non-degradable materials PS and PET with 1% of mass fraction were added to PBAT, they could also be detected. This method was used for the analysis of samples of degradable plastic shopping bags collected in the market. It was shown that PY-GC-MS could be used for rapid preliminary identification of degradable plastics.