{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,19]],"date-time":"2026-04-19T18:36:35Z","timestamp":1776623795828,"version":"3.51.2"},"reference-count":56,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2020,11,28]],"date-time":"2020-11-28T00:00:00Z","timestamp":1606521600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","award":["DL 57\/2016\/CP1382\/CT0018"],"award-info":[{"award-number":["DL 57\/2016\/CP1382\/CT0018"]}]},{"name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","award":["DL 57\/2016\/CP1382\/CT0007"],"award-info":[{"award-number":["DL 57\/2016\/CP1382\/CT0007"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>The changes in the cellulose structure of eight Eucalyptus species (E. botryoides, E. globulus, E. grandis, E. maculata, E. propinqua, E. rudis, E. saligna and E. viminalis) in a mild torrefaction (from 160 \u00b0C to 230 \u00b0C, 3 h) were studied in situ and after cellulose isolation from the wood by solid-state carbon nuclear magnetic resonance (13C 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%\u20133%) 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.<\/jats:p>","DOI":"10.3390\/polym12122831","type":"journal-article","created":{"date-parts":[[2020,11,28]],"date-time":"2020-11-28T03:51:16Z","timestamp":1606535476000},"page":"2831","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":34,"title":["Cellulose Structural Changes during Mild Torrefaction of Eucalyptus Wood"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4896-344X","authenticated-orcid":false,"given":"Ana","family":"Louren\u00e7o","sequence":"first","affiliation":[{"name":"Forest Research Center, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017 Lisboa, Portugal"}]},{"given":"Solange","family":"Ara\u00fajo","sequence":"additional","affiliation":[{"name":"Forest Research Center, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3419-6075","authenticated-orcid":false,"given":"Jorge","family":"Gominho","sequence":"additional","affiliation":[{"name":"Forest Research Center, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6304-5105","authenticated-orcid":false,"given":"Dmitry","family":"Evtuguin","sequence":"additional","affiliation":[{"name":"CICECO, Chemistry Department, University of Aveiro, Campus de Santiago, P-3810-193 Aveiro, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2020,11,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"575","DOI":"10.1016\/j.matdes.2012.12.067","article-title":"Characterization of heat treated wood species","volume":"49","author":"Priadi","year":"2013","journal-title":"Mater. Des."},{"key":"ref_2","first-page":"363","article-title":"Chemical Modification of Wood","volume":"6","author":"Rowell","year":"1983","journal-title":"Forest Prod. Abstr."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Rowell, R.M. (2013). Biological properties of wood. Handbook of Chemistry and Wood Composites, Taylor Francis. [2nd ed.].","DOI":"10.1201\/b12487"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Rowell, R.M. (2013). Weathering of wood and wood composites. Handbook of Chemistry and Wood Composites, Taylor Francis. [2nd ed.].","DOI":"10.1201\/b12487"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Jones, D., and Brischke, C. (2017). Performance of Bio-Based Building Materials, Woodhead Publishing, Elsevier Ltd.","DOI":"10.1016\/B978-0-08-100982-6.00001-X"},{"key":"ref_6","first-page":"19","article-title":"The effect of different methods of drying on the strength of wood","volume":"28","author":"Tiemann","year":"1915","journal-title":"Lumber World Rev."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"831","DOI":"10.1021\/ie50331a021","article-title":"Minimizing wood shrinkage and swelling effect of heating in various gasses","volume":"29","author":"Stamm","year":"1937","journal-title":"Ind. Eng. Chem."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1285","DOI":"10.1007\/s00226-013-0574-3","article-title":"A review of wood thermal pretreatments to improve wood composite properties","volume":"47","author":"Yadama","year":"2013","journal-title":"Wood Sci. Technol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"370","DOI":"10.15376\/biores.4.1.Esteves","article-title":"Wood modification by heat treatment: A Review","volume":"4","author":"Esteves","year":"2009","journal-title":"Bioresources"},{"key":"ref_10","first-page":"28","article-title":"Thermal modified timber: Recent developments in Europe and North America","volume":"48","author":"Sandberg","year":"2016","journal-title":"Wood Fiber. Sci."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1007\/s001070050287","article-title":"Characterisation of thermally modified wood: Molecular reasons for wood performance improvement","volume":"56","author":"Tjeerdsma","year":"1998","journal-title":"Holz als Roh-und Werkst."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"5865","DOI":"10.1021\/acs.energyfuels.5b01263","article-title":"Effect of torrefaction on biomass physicochemical characteristics and the resulting pyrolysis behavior","volume":"29","author":"Ru","year":"2015","journal-title":"Energy Fuels"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2426","DOI":"10.1016\/j.rser.2017.08.095","article-title":"Biomass Torrefaction for Energy Purposes\u2014Definitions and an Overview of Challenges and Opportunities in Brazil","volume":"82","author":"Silva","year":"2018","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1763","DOI":"10.1016\/S1352-2310(02)00152-8","article-title":"Comparing the VOC emissions between air-dried and heat-treated Scots pine wood","volume":"36","author":"Manninen","year":"2002","journal-title":"Atmos. Environ."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1016\/j.ijbiomac.2014.02.013","article-title":"Investigation of structural modification and thermal characteristics of lignin after heat treatment","volume":"66","author":"Kim","year":"2014","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"258","DOI":"10.1080\/02773813.2020.1769674","article-title":"Structural changes in lignin of thermally treated eucalyptus wood","volume":"40","author":"Gominho","year":"2020","journal-title":"J. Wood Chem. Technol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/BF00818796","article-title":"Cellulose: A random walk along its historical path","volume":"1","author":"Hon","year":"1994","journal-title":"Cellulose"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"431","DOI":"10.1007\/BF00765800","article-title":"Changes of crystallinity in wood cellulose by heat treatment under drier and moist conditions","volume":"46","author":"Bhuiyan","year":"2000","journal-title":"J. Wood Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"336","DOI":"10.1007\/BF00766782","article-title":"Effect of intermittent heat treatment on crystallinity in wood cellulose","volume":"47","author":"Bhuiyan","year":"2001","journal-title":"J. Wood Sci."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"92","DOI":"10.3832\/ifor2723-011","article-title":"Changes in moisture exclusion efficiency and crystallinity of thermally modified wood with aging","volume":"12","author":"Tarmian","year":"2019","journal-title":"iForest-Biogeosciences For."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Kubovsk\u00fd, I., Ka\u010d\u00edkov\u00e1, D., and Ka\u010d\u00edk, F. (2020). Structural changes of oak wood main components caused by thermal modification. Polymers, 12.","DOI":"10.3390\/polym12020485"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1016\/j.fuel.2011.06.042","article-title":"NMR analysis of the transformation of wood constituents by torrefaction","volume":"92","author":"Melkior","year":"2012","journal-title":"Fuel"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"92","DOI":"10.1016\/j.biombioe.2013.04.025","article-title":"Chemical and cellulose crystallite changes in Pinus radiata during torrefaction","volume":"56","author":"Hill","year":"2013","journal-title":"Biomass Bioenergy"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"461","DOI":"10.1016\/j.carbpol.2004.08.008","article-title":"Characterization of thermally modified hard and softwoods by 13C CPMAS NMR","volume":"58","author":"Wikberg","year":"2004","journal-title":"Carbohydr. Polym."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1016\/j.buildenv.2005.07.009","article-title":"The effects of thermal modification on crystalline structure of cellulose in soft and hardwood","volume":"42","author":"Yildiz","year":"2007","journal-title":"Build. Environ."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1080\/17480272.2018.1450783","article-title":"Relation of chemical and mechanical properties of Eucalyptus nitens wood thermally modified in open and closed systems","volume":"14","author":"Wentzel","year":"2019","journal-title":"Wood Mater. Sci. Eng."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"4839","DOI":"10.1039\/C3GC42570C","article-title":"Characterization of biomass and its derived char using 13C solid state nuclear magnetic resonance","volume":"16","author":"Baccile","year":"2014","journal-title":"Green Chem."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"291","DOI":"10.1515\/hf-2016-0079","article-title":"Chemical effects of a mild torrefaction on the wood of eight Eucalyptus species","volume":"71","author":"Neiva","year":"2017","journal-title":"Holzforschung"},{"key":"ref_29","unstructured":"Browning, B.L. (1967). Methods in Wood Chemistry, John Wiley& Sons."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"597","DOI":"10.1016\/S0008-6215(02)00529-3","article-title":"Characterization of acetylated heteroxylan from Eucalyptus globulus Labill","volume":"338","author":"Evtuguin","year":"2003","journal-title":"Carbohydr. Res."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"2625","DOI":"10.1007\/s10570-018-2210-8","article-title":"The effects of transition metal sulfates on cellulose crystallinity during accelerated ageing of silver fir wood","volume":"26","author":"Evtuguin","year":"2019","journal-title":"Cellulose"},{"key":"ref_32","first-page":"3","article-title":"Study on the cellulose crystallinity in plant materials","volume":"5","author":"Ioelovitch","year":"1989","journal-title":"Khimiya Drev."},{"key":"ref_33","unstructured":"Bikales, N.M., and Segal, L. (1971). Measurement of crystallinity. Cellulose and Cellulose Derivatives, Wiley-Interscience. Part IV."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1186\/s13068-017-0718-z","article-title":"Understanding the structural and chemical changes of plant biomass following steam explosion pretreatment","volume":"10","author":"Auxenfans","year":"2017","journal-title":"Biotechnol. Biofuels"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"618","DOI":"10.1515\/HF.2000.104","article-title":"Solid-state NMR studies on cellulose crystallinity in fines and bulk fibres separated from refined kraft pulp","volume":"54","author":"Maunu","year":"2000","journal-title":"Holzforschung"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1016\/S0008-6215(98)00236-5","article-title":"Assignment of non-crystalline forms in cellulose I by CP\/MAS 13C NMR spectroscopy","volume":"312","author":"Wickholm","year":"1998","journal-title":"Carbohydr. Res."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1426","DOI":"10.1021\/jf00008a014","article-title":"Pyrolysis-GC-MS characterization of forage materials","volume":"39","author":"Ralph","year":"1991","journal-title":"J. Agric. Food Chem."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1007\/BF02663795","article-title":"Thermal degradation products of wood. A collection of electron-impact (EI) mass spectra of polysaccharide derived products","volume":"49","author":"Faix","year":"1991","journal-title":"Holz als Roh-und Werkst."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"2331","DOI":"10.1002\/app.1989.070370822","article-title":"Cellulose molecular weights determined by viscometry","volume":"37","author":"Evans","year":"1989","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"192","DOI":"10.1016\/j.biortech.2015.12.007","article-title":"Structural and chemical modifications of typical South African biomasses during torrefaction","volume":"202","author":"Mafu","year":"2016","journal-title":"Biores. Technol."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"3863","DOI":"10.1021\/ef5004683","article-title":"Impact of torrefaction on the chemical structure of birch wood","volume":"28","author":"Shoulaifar","year":"2014","journal-title":"Energy Fuels"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1039\/C6RE00176A","article-title":"Energetics of cellulose and cyclodextrin glycosidic bond cleavage","volume":"2","author":"Zhu","year":"2017","journal-title":"React. Chem. Eng."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2846","DOI":"10.1021\/jz201182w","article-title":"Computational study of bond dissociation enthalpies for a large range of native and modified lignins","volume":"2","author":"Kim","year":"2011","journal-title":"J. Phys. Chem. Lett."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"381","DOI":"10.1016\/j.energy.2015.12.120","article-title":"Study of solid chemical evolution in torrefaction of different biomasses through solid-state 13C cross-polarization\/magic angle spinning NMR (nuclear magnetic resonance) and TGA (thermogravimetric analysis)","volume":"97","author":"Alonso","year":"2016","journal-title":"Energy"},{"key":"ref_45","first-page":"135","article-title":"Effect of thermal treatment on functional groups and degree of cellulose crystallinity of eucalyptus wood (Eucalyptus grandis x Eucalyptus urophylla)","volume":"67","author":"Cheng","year":"2017","journal-title":"For. Prod. J."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"3309","DOI":"10.1016\/S0032-3861(00)00774-6","article-title":"Cellulose fibril aggregation\u2014An inherent property of kraft pulps","volume":"42","author":"Hult","year":"2001","journal-title":"Polymer"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1023\/B:CELL.0000014768.28924.0c","article-title":"Carbon-13 NMR evidence for cocrystallization of cellulose as a mechanism for hornification of bleached kraft pulp","volume":"11","author":"Newman","year":"2004","journal-title":"Cellulose"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0926-2040(99)00042-9","article-title":"The role of solid state 13C NMR spectroscopy in studies of the nature of native celluloses","volume":"15","author":"Atalla","year":"1999","journal-title":"Solid State Nucl. Magn. Reson."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/S0065-2318(10)64003-6","article-title":"Structure and Engineering of Celluloses","volume":"64","author":"Samain","year":"2010","journal-title":"Adv. Carbohydr. Chem. Biochem."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"183","DOI":"10.1023\/A:1013196220602","article-title":"Localization of I\u03b1 and I\u03b2 phases in algal cellulose revealed by acid treatments","volume":"8","author":"Wada","year":"2001","journal-title":"Cellulose"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"421","DOI":"10.1590\/S1516-14392012005000048","article-title":"Materials Produced From Plant Biomass. Part II: Evaluation of Crystallinity and Degradation Kinetics of Cellulose","volume":"15","author":"Polettoa","year":"2012","journal-title":"Mater. Res."},{"key":"ref_52","unstructured":"Kusch, P. (2019). Chemical characterization of lignocellulosic materials by analytical pyrolysis. Analytical Pyrolysis, InTechOpen. Available online: https:\/\/www.intechopen.com\/books\/analytical-pyrolysis\/chemical-characterization-of-lignocellulosic-materials-by-analytical-pyrolysis."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"1809","DOI":"10.1016\/S0016-2361(01)00064-3","article-title":"Real-time evolved gas analysis by FTIR method: An experimental study of cellulose pyrolysis","volume":"80","author":"Li","year":"2001","journal-title":"Fuel"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"722","DOI":"10.1016\/j.biortech.2011.10.078","article-title":"Mechanism research on cellulose pyrolysis by Py-GC\/MS and subsequent density functional theory studies","volume":"104","author":"Wang","year":"2012","journal-title":"Bioresour. Technol."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1016\/j.jaap.2012.11.017","article-title":"Effect of cellulose crystallinity on the formation of a liquid intermediate and on product distribution during pyrolysis","volume":"100","author":"Had","year":"2013","journal-title":"J. Anal. Appl. Pyrolysis"},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"5859","DOI":"10.1039\/D0GC01490G","article-title":"Levoglucosan: A promising platform molecule?","volume":"22","author":"Junior","year":"2020","journal-title":"Green Chem."}],"container-title":["Polymers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4360\/12\/12\/2831\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T10:38:48Z","timestamp":1760179128000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4360\/12\/12\/2831"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,11,28]]},"references-count":56,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2020,12]]}},"alternative-id":["polym12122831"],"URL":"https:\/\/doi.org\/10.3390\/polym12122831","relation":{},"ISSN":["2073-4360"],"issn-type":[{"value":"2073-4360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,11,28]]}}}