title: Specific molecular structure changes and radical evolution during biomass-polyethylene terephthalate co-pyrolysis detected by (13)C and (1)H solid-state NMR.
abstract: Co-pyrolysis of biomass with polyethylene terephthalate (PET) was studied as a function of blend ratio and co-pyrolysis temperature by (13)C and (1)H solid-state nuclear magnetic resonance (NMR). The (13)C NMR spectra showed that upon heating to 400°C in presence of the biomass, the formation of crystallites in PET was completely suppressed and that at higher temperatures there was increased formation and growth of the polycyclic aromatic hydrocarbons (PAHs). This change in the PET degradation behaviour was attributed to the presence of radicals formed in char from biomass. The measurement of the (1)H-T1 relaxation enabled monitoring the changes in the concentrations of radicals formed, as a function of the blend ratios and the co-pyrolysis temperatures. It indicated that the increase in the radical concentrations correlated well with the increased degradation of the PET and growth of PAHs.
authors.affiliation: Centre for Sustainable Materials Research & Technology (SMaRT), School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: Kwang-Hyun
authors.initials: KH
authors.lastname: Ko
authors.affiliation: Centre for Sustainable Materials Research & Technology (SMaRT), School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: Veena
authors.initials: V
authors.lastname: Sahajwalla
authors.affiliation: Nuclear Magnetic Resonance Facility, Mark Wainwright Analytical Centre, University of New South Wales, Sydney, NSW 2052, Australia. Electronic address: a.rawal@unsw.edu.au.
authors.forename: Aditya
authors.initials: A
authors.lastname: Rawal
mesh_terms: D056804:Biofuels; D018533:Biomass; D002247:Carbon Isotopes / Q000032:analysis; D005609:Free Radicals / Q000737:chemistry; D006358:Hot Temperature; D008279:Magnetic Resonance Imaging / Q000379:methods; D008956:Models, Chemical; D011084:Polycyclic Aromatic Hydrocarbons / Q000138:chemical synthesis; D011093:Polyethylene Terephthalates / Q000737:chemistry*
chemical_list: D056804:Biofuels; D002247:Carbon Isotopes; D005609:Free Radicals; D011084:Polycyclic Aromatic Hydrocarbons; D011093:Polyethylene Terephthalates
keywords: (1)H NMR; (13)C NMR; Co-pyrolysis; Cross-linking reaction; Radical