RESUMO
The biodegradability of three types of bioplastic pots was evaluated by measuring carbon dioxide produced from lab-scale compost reactors containing mixtures of pot fragments and compost inoculum held at 58 °C for 60 days. Biodegradability of pot type A (composed of 100% polylactic acid (PLA)) was very low (13 ± 3%) compared to literature values for other PLA materials. Near infrared spectroscopy (NIRS) results suggest that the PLA undergoes chemical structural changes during polymer extrusion and injection molding. These changes may be the basis of the low biodegradability value. Biodegradability of pot types B (containing 5% poultry feather, 80% PLA, 15% starch), and C (containing 50% poultry feather, 25% urea, 25% glycerol), were 53 ± 2% and 39 ± 3%, respectively. More than 85% of the total biodegradation of these bioplastics occurred within 38 days. NIRS results revealed that poultry feather was not degraded during composting.
Assuntos
Plumas/metabolismo , Ácido Láctico/metabolismo , Plásticos/metabolismo , Polímeros/metabolismo , Animais , Biodegradação Ambiental , Glicerol , Plásticos/química , Poliésteres , Aves Domésticas , Espectroscopia de Luz Próxima ao Infravermelho , Fatores de Tempo , UreiaRESUMO
Lignin samples from wheat straw, orchard grass, red clover and a synthetic lignin were subjected to pyrolysis gas chromatography/mass spectrometry using both quadrupole (QMS) and ion-trap detector (ITD). ITD mass spectra were comparable with those presented in the National Bureau of Standards (NBS) library and with those obtained by QMS as evaluated by discrepancy factors. Computer-assisted library searches for ITD spectra were successful for 22 of 47 compounds. The other 25 compounds were not present in the library. A typical program and mass spectra are shown. Statistical data are discussed.