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- Products of the permanganate oxidation of Cork, desuberized Cork, suberin and lignin from Quercus suber L.Publication . Lopes, M.; Neto, C. Pascoal; Evtuguin, D.; Silvestre, A. J. D.; Gil, A.; Cordeiro, N.; Gandini, A.
- Cork suberin as a new source of chemicals: 2. crystallinity, thermal and rheological propertiesPublication . Cordeiro, N.; Belgacem, N.M.; Gandini, A.; Neto, C. PascoalSuberin samples, obtained by alkaline methanolysis from cork (Quercus suber L.), were submitted to various physical characterizations; DSC, TGA, optical microscopy, density and rheological properties. A sub stantial proportion of these oligomers possessed a microcrystalline character with a melting range between 0 and 50°C. The amorphous part was liquid at room temperature and did not display a detectable glass transition upon cooling because of its wide molecular weight distribution. The viscous behaviour of suberin at room temperature was both plastic and thixotropic because of the structuring role of the microcrystals.
- Isolation and characterization of a lignin-like polymer of the cork of Quercus suber LPublication . Neto, C. Pascoal; Cordeiro, N.; Seca, A.; Domingues, F.; Gandini, A.; Robert, D.A lignin-like polymer was successfully extracted from the cork of Quercus suber L. using an organosolv-based technique. This material was characterized by elemental analysis, functional group analysis, nitrobenzene oxidation followed by HPLC analysis of the oxidation products, FTIR and liquid I3C NMR. The evidence thus obtained indicated that the extracted material was composed mainly of a lignin-like polymer covalently bound to residual aliphatic structures which are not present in common lignins and which have been assigned to suberin. The latter is likely to be attached to the oxygenated side chains of the phenolic polymer but bonding through the aromatic ring can also be envisaged. No residual carbohydrates were detected. The phenolic polymer, composed mainly of guaiacyl-type units and small amounts of syringyl-type units, had a low methoxy content and a high degree of condensation. This polymer showed the presence of a fraction containing CeCn units with n < 3 or even n < 2.