Cellulose Structural Changes during Mild Torrefaction of <i>Eucalyptus</i> Wood
The changes in the cellulose structure of eight <i>Eucalyptus</i> species (<i>E. botryoides</i>, <i>E. globulus</i>, <i>E. grandis</i>, <i>E. maculata</i>, <i>E. propinqua</i>, <i>E. rudis</i>, <i>E. saligna<...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-11-01
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| Series: | Polymers |
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| Online Access: | https://www.mdpi.com/2073-4360/12/12/2831 |
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| author | Ana Lourenço Solange Araújo Jorge Gominho Dmitry Evtuguin |
| author_facet | Ana Lourenço Solange Araújo Jorge Gominho Dmitry Evtuguin |
| author_sort | Ana Lourenço |
| collection | DOAJ |
| description | The changes in the cellulose structure of eight <i>Eucalyptus</i> species (<i>E. botryoides</i>, <i>E. globulus</i>, <i>E. grandis</i>, <i>E. maculata</i>, <i>E. propinqua</i>, <i>E. rudis</i>, <i>E. saligna</i> and <i>E. viminalis</i>) in a mild torrefaction (from 160 °C to 230 °C, 3 h) were studied in situ and after cellulose isolation from the wood by solid-state carbon nuclear magnetic resonance (<sup>13</sup>C NMR), wide angle X-ray scattering (WAXS), Fourier transform infrared spectroscopy (FTIR) and by analytic pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS). Changes in molecular weight were assessed by viscosimetry. A small decrease in cellulose crystallinity (ca. 2%–3%) was attributed to its amorphization on crystallite surfaces as a result of acid hydrolysis and free radical reactions resulting in the homolytic splitting of glycosidic bonds. The degree of the cellulose polymerization (DPv) decreased more than twice during the heat treatment of wood. It has been proposed that changes in the supramolecular structure of cellulose and in molecular weight during a heat treatment can be affected by the amount of lignin present in the wood. The limitations of FTIR and Py-GC/MS techniques to distinguish the minor changes in cellulose crystallinity were discussed. |
| first_indexed | 2024-03-10T14:29:21Z |
| format | Article |
| id | doaj.art-a78f69bf5d12437985fc4b9fee7c5177 |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-03-10T14:29:21Z |
| publishDate | 2020-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Polymers |
| spelling | doaj.art-a78f69bf5d12437985fc4b9fee7c51772023-11-20T22:43:08ZengMDPI AGPolymers2073-43602020-11-011212283110.3390/polym12122831Cellulose Structural Changes during Mild Torrefaction of <i>Eucalyptus</i> WoodAna Lourenço0Solange Araújo1Jorge Gominho2Dmitry Evtuguin3Forest Research Center, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017 Lisboa, PortugalForest Research Center, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017 Lisboa, PortugalForest Research Center, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017 Lisboa, PortugalCICECO, Chemistry Department, University of Aveiro, Campus de Santiago, P-3810-193 Aveiro, PortugalThe changes in the cellulose structure of eight <i>Eucalyptus</i> species (<i>E. botryoides</i>, <i>E. globulus</i>, <i>E. grandis</i>, <i>E. maculata</i>, <i>E. propinqua</i>, <i>E. rudis</i>, <i>E. saligna</i> and <i>E. viminalis</i>) in a mild torrefaction (from 160 °C to 230 °C, 3 h) were studied in situ and after cellulose isolation from the wood by solid-state carbon nuclear magnetic resonance (<sup>13</sup>C NMR), wide angle X-ray scattering (WAXS), Fourier transform infrared spectroscopy (FTIR) and by analytic pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS). Changes in molecular weight were assessed by viscosimetry. A small decrease in cellulose crystallinity (ca. 2%–3%) was attributed to its amorphization on crystallite surfaces as a result of acid hydrolysis and free radical reactions resulting in the homolytic splitting of glycosidic bonds. The degree of the cellulose polymerization (DPv) decreased more than twice during the heat treatment of wood. It has been proposed that changes in the supramolecular structure of cellulose and in molecular weight during a heat treatment can be affected by the amount of lignin present in the wood. The limitations of FTIR and Py-GC/MS techniques to distinguish the minor changes in cellulose crystallinity were discussed.https://www.mdpi.com/2073-4360/12/12/2831cellulose crystallinitythermal treatment<i>Eucalyptus</i> woodWAXSsolid-state <sup>13</sup>C NMRFTIR |
| spellingShingle | Ana Lourenço Solange Araújo Jorge Gominho Dmitry Evtuguin Cellulose Structural Changes during Mild Torrefaction of <i>Eucalyptus</i> Wood Polymers cellulose crystallinity thermal treatment <i>Eucalyptus</i> wood WAXS solid-state <sup>13</sup>C NMR FTIR |
| title | Cellulose Structural Changes during Mild Torrefaction of <i>Eucalyptus</i> Wood |
| title_full | Cellulose Structural Changes during Mild Torrefaction of <i>Eucalyptus</i> Wood |
| title_fullStr | Cellulose Structural Changes during Mild Torrefaction of <i>Eucalyptus</i> Wood |
| title_full_unstemmed | Cellulose Structural Changes during Mild Torrefaction of <i>Eucalyptus</i> Wood |
| title_short | Cellulose Structural Changes during Mild Torrefaction of <i>Eucalyptus</i> Wood |
| title_sort | cellulose structural changes during mild torrefaction of i eucalyptus i wood |
| topic | cellulose crystallinity thermal treatment <i>Eucalyptus</i> wood WAXS solid-state <sup>13</sup>C NMR FTIR |
| url | https://www.mdpi.com/2073-4360/12/12/2831 |
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