{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,16]],"date-time":"2026-07-16T20:18:38Z","timestamp":1784233118534,"version":"3.55.0"},"reference-count":85,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2023,10,5]],"date-time":"2023-10-05T00:00:00Z","timestamp":1696464000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic and Slovak Academy of Sciences","award":["1\/0117\/22"],"award-info":[{"award-number":["1\/0117\/22"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>This work examines the effect of thermal modification temperature (180, 200, and 220 \u00b0C) in comparison with reference (untreated) samples on selected optical properties of six tropical wood species\u2014Sp. cedar (Cedrala odorata), iroko (Chlorophora excelsa), merbau (Intsia spp.), meranti (Shorea spp.), padouk (Pterocarpus soyauxii), and teak (Tectona grandis). The main goal is to expand the existing knowledge in the field of wood thermal modification by understanding the related degradation mechanisms associated with the formation of chromophoric structures and, above all, to focus on the change in the content of extractive substances. For solid wood, the CIELAB color space parameters (L*, a*, b*, and \u0394E*), yellowness (Y), ISO brightness, and UV-Vis diffuse reflectance spectra were obtained. Subsequently, these wood samples were extracted into three individual solvents (acetone, ethanol, and ethanol-toluene). The yields of the extracted compounds, their absorption spectra, and again L*, a*, b*, \u0394E*, and Yi parameters were determined. With increasing temperatures, the samples lose brightness and darken, while their total color difference grows (except merbau). The highest yield of extractives (mainly phenolic compounds, glycosides, and dyes) from thermally modified samples was usually obtained using ethanol. New types of extractives (e.g., 2-furaldehyde, lactones, formic acid, some monomer derivatives of phenols, etc.) are already created around a temperature of 180 \u00b0C and may undergo condensation reactions at higher temperatures. For padouk, merbau, teak, and partially iroko modified at temperatures of 200 and 220 \u00b0C, there was a detected similarity in the intensities of their UV-Vis DR spectra at the wavelength regions corresponding to phenolic aldehydes, unsaturated ketones, quinones, stilbenes, and other conjugated carbonyl structures. Overall, a statistical assessment using PCA sorted the samples into five clusters. Cluster 3 consists of almost all samples modified at 200 and 220 \u00b0C, and in the other four, the reference and thermally modified samples at 180 \u00b0C were distributed. The yellowness of wood (Y) has a very high dependence (r = 0.972) on its brightness (L*) and the yellowness index of the extractives in acetone Yi(Ac), whose relationship was described by the equation Y = \u22120.0951 \u00d7 Y(Ac) + 23.3485.<\/jats:p>","DOI":"10.3390\/polym15194000","type":"journal-article","created":{"date-parts":[[2023,10,5]],"date-time":"2023-10-05T09:14:22Z","timestamp":1696497262000},"page":"4000","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Chromophores\u2019 Contribution to Color Changes of Thermally Modified Tropical Wood Species"],"prefix":"10.3390","volume":"15","author":[{"given":"Tereza","family":"Jurczykov\u00e1","sequence":"first","affiliation":[{"name":"Department of Wood Processing and Biomaterials, Faculty of Forestry and Wood Sciences, Czech University of Life Science Prague, Kam\u00fdck\u00e1 129, 165 21 Prague, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ond\u0159ej","family":"\u0160\u00e1rovec","sequence":"additional","affiliation":[{"name":"Department of Wood Processing and Biomaterials, Faculty of Forestry and Wood Sciences, Czech University of Life Science Prague, Kam\u00fdck\u00e1 129, 165 21 Prague, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8989-0833","authenticated-orcid":false,"given":"Franti\u0161ek","family":"Ka\u010d\u00edk","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Chemical Technology, Faculty of Wood Sciences and Technology, Technical University in Zvolen, T. G. Masaryka 24, 960 01 Zvolen, Slovakia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2481-1292","authenticated-orcid":false,"given":"Kate\u0159ina","family":"H\u00e1jkov\u00e1","sequence":"additional","affiliation":[{"name":"Department of Wood Processing and Biomaterials, Faculty of Forestry and Wood Sciences, Czech University of Life Science Prague, Kam\u00fdck\u00e1 129, 165 21 Prague, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tom\u00e1\u0161","family":"Jurczyk","sequence":"additional","affiliation":[{"name":"TIBCO Software s.r.o., Klimentsk\u00e1 1216\/46, 110 00 Prague, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0704-8958","authenticated-orcid":false,"given":"Richard","family":"Hr\u010dka","sequence":"additional","affiliation":[{"name":"Department of Wood Science, Faculty of Wood Sciences and Technology, Technical University in Zvolen, T. G. Masaryka 24, 960 01 Zvolen, Slovakia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,10,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Hon, D.N.S., and Shiraishi, N. (2001). Wood and Cellulosic Chemistry, Marcel Dekker.","DOI":"10.1201\/9781482269741"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1007\/s00107-017-1228-1","article-title":"The impact of natural and artificial weathering on the visual, color, and structural changes of seven tropical woods","volume":"76","author":"Reinprecht","year":"2018","journal-title":"Eur. J. Wood Wood Prod."},{"key":"ref_3","unstructured":"Panshin, A.J., and de Zeeuw, C. (1980). Textbook of Wood Technology, McGraw-Hill Book Company."},{"key":"ref_4","first-page":"24","article-title":"Chromophores in aged hardwood pulp\u2014Their structure and degradation potential","volume":"1","author":"Rosenau","year":"2008","journal-title":"Tappi J."},{"key":"ref_5","first-page":"659","article-title":"Assessment of Chromophores in Chemically Treated and Aged Wood by UV-Vis Diffuse Reflectance Spectroscopy","volume":"50","author":"Evtuguin","year":"2016","journal-title":"Cellul. Chem. Technol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"303","DOI":"10.1007\/BF00353246","article-title":"Thermal treatment of wood: Analysis of the obtained product","volume":"23","author":"Bourgois","year":"1989","journal-title":"Wood Sci. Technol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"6581","DOI":"10.1007\/s10853-020-05722-z","article-title":"Thermal modification of wood\u2014A review: Chemical changes and hygroscopicity","volume":"56","author":"Hill","year":"2021","journal-title":"J. Mater. Sci."},{"key":"ref_8","unstructured":"Reinprecht, L., and Vidholdov\u00e1, Z. (2008). ThermoWood\u2013Preparing, Properties and Applications, Technical University in Zvolen. (In Slovak)."},{"key":"ref_9","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_10","doi-asserted-by":"crossref","first-page":"1157","DOI":"10.15376\/biores.7.1.1157-1170","article-title":"The effect of heat treatment on the chemical and color change of black locust (Robinia pseudoacacia) wood flour","volume":"7","author":"Chen","year":"2012","journal-title":"BioResources"},{"key":"ref_11","first-page":"2236","article-title":"Heat-induced chemical and color changes of extractive-free black locust (Robinia pseudoacacia) wood","volume":"7","author":"Chen","year":"2012","journal-title":"BioResources"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"5360","DOI":"10.1016\/j.apsusc.2012.02.005","article-title":"A spectrocolorimetric and chemical study on color modification of heat-treated wood during artificial weathering","volume":"258","author":"Huang","year":"2012","journal-title":"Appl. Surf. Sci."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"e023","DOI":"10.5424\/fs\/2022313-19558","article-title":"Effect of heat treatment on hardness, density and color of Populus\u00d7 canadensis \u2018I-214\u2032wood","volume":"31","author":"Taraborelli","year":"2022","journal-title":"For. Syst."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"348","DOI":"10.1016\/j.matdes.2012.06.054","article-title":"Properties of some thermally modified wood species","volume":"43","author":"Bakar","year":"2013","journal-title":"Mater. Des."},{"key":"ref_15","first-page":"138","article-title":"Thermal behavior of Scots pine (Pinus sylvestris) and silver birch (Betula pendula) at 200\u2013230","volume":"32","author":"Zaman","year":"2000","journal-title":"Wood Fiber Sci."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1762","DOI":"10.1016\/j.buildenv.2005.07.017","article-title":"Mechanical and chemical behavior of spruce wood modified by heat","volume":"41","author":"Yildiz","year":"2006","journal-title":"Build. Environ."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1007\/s00226-010-0389-4","article-title":"The fracture toughness and properties of thermally modified beech and ash at different moisture contents","volume":"46","author":"Hughes","year":"2012","journal-title":"Wood Sci. Technol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"439","DOI":"10.22382\/wfs-2018-055","article-title":"Color changes, EMC, and biological resistance of thermally modified yellow poplar","volume":"50","author":"Brito","year":"2018","journal-title":"Wood Fiber Sci."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Ka\u010d\u00edkov\u00e1, D., Kubovsk\u00fd, I., Gaff, M., and Ka\u010d\u00edk, F. (2021). Changes of Meranti, Padauk, and Merbau Wood Lignin during the ThermoWood Process. Polymers, 13.","DOI":"10.3390\/polym13070993"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Ka\u010d\u00edkov\u00e1, D., Kubovsk\u00fd, I., Ulbrikov\u00e1, N., and Ka\u010d\u00edk, F. (2020). The impact of thermal treatment on structural changes of teak and iroko wood lignins. Appl. Sci., 10.","DOI":"10.3390\/app10145021"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2667","DOI":"10.15376\/biores.14.2.2667-2683","article-title":"Color and chemical changes in teak (Tectona grandis L. f.) and meranti (Shorea spp.) wood after thermal treatment","volume":"14","author":"Gaff","year":"2019","journal-title":"BioResources"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"20220277","DOI":"10.1515\/rams-2022-0277","article-title":"Impact of thermal modification on color and chemical changes of African padauk, merbau, mahogany, and iroko wood species","volume":"62","author":"Gaff","year":"2023","journal-title":"Rev. Adv. Mater. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"355","DOI":"10.1016\/j.indcrop.2011.10.004","article-title":"Performance of three thermally treated tropical wood species commonly used in Turkey","volume":"36","author":"Korkut","year":"2012","journal-title":"Ind. Crops Prod."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"3478","DOI":"10.1016\/j.biortech.2006.11.006","article-title":"Evaluation of thermally modified Grevillea robusta heartwood as an alternative to shortage of wood resource in Kenya: Characterisation of physicochemical properties and improvement of bio-resistance","volume":"98","author":"Mburu","year":"2007","journal-title":"Bioresour. Technol."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Lengowski, E.C., Bonfatti J\u00fanior, E.A., Nisgoski, S., Bolzon de Mu\u00f1iz, G.I., and Klock, U. (2021). Properties of thermally modified teakwood. Maderas Cienc. Y Tecnol., 23.","DOI":"10.4067\/S0718-221X2021000100410"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"661","DOI":"10.1007\/s00226-010-0356-0","article-title":"Chemistry and ecotoxicity of heat-treated pine wood extractives","volume":"45","author":"Esteves","year":"2011","journal-title":"Wood Sci. Technol."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Piernik, M., Wo\u017aniak, M., Pinkowski, G., Szentner, K., Ratajczak, I., and Krauss, A. (2022). Impact of the Heat Treatment Duration on Color and Selected Mechanical and Chemical Properties of Scots Pine Wood. Materials, 15.","DOI":"10.3390\/ma15155425"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"73","DOI":"10.3390\/f14010073","article-title":"Color and Chemical Changes of Black Locust Wood during Heat Treatment","volume":"14","author":"Gaff","year":"2022","journal-title":"Forests"},{"key":"ref_29","unstructured":"Meier, E. (2021). The Wood Dictionary: From Acacia to Ziricote, a Guide to the World\u2019s Wood, Sierra\u2019s Ascent Publisher."},{"key":"ref_30","unstructured":"Wagenf\u00fchr, R. (2007). Holzatlas, Fachbuchverlag Publisher. [6th ed.]."},{"key":"ref_31","unstructured":"International Thermowood Association (2021). Thermowood Handbook, International Thermowood Association."},{"key":"ref_32","unstructured":"(2011). Sampling and Preparing Wood for Analysis. Technical Association of the Pulp and Paper Industry. Standard No. TAPPI T 257 cm-02."},{"key":"ref_33","unstructured":"(2021). Standard Test Method for Ethanol-Toluene Solubility of Wood. Standard No. ASTM D 1107\u201396."},{"key":"ref_34","unstructured":"(1990). Paper, board, and pulps\u2014Standard atmosphere for conditioning and testing and procedure for monitoring the atmosphere and conditioning of samples. Standard No. ISO 187."},{"key":"ref_35","unstructured":"(2011). Colorimetry\u2013Part 4: CIE 1976 L*a*b* colour space. Standard No. ISO 11664-4."},{"key":"ref_36","unstructured":"(2014). ISO\/CIE 11664-6Colorimetry\u2013Part 6: CIEDE2000 Color-difference formula."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"448","DOI":"10.1364\/JOSA.38.000448","article-title":"New contributions to the optics of intensely light-scattering materials. Part I","volume":"38","author":"Kubelka","year":"1948","journal-title":"J. Opt. Soc. Am."},{"key":"ref_38","unstructured":"(2000). TAPPI T 280 pm-99Acetone extractives of wood and pulp. Technical Association of the Pulp and Paper Industry."},{"key":"ref_39","unstructured":"(1997). TAPPI T 204 cm-97Solvent extractives of wood and pulp. Technical Association of the Pulp and Paper Industry."},{"key":"ref_40","unstructured":"(1997). TAPPI T 264 cm-97Preparation of wood for chemical analysis. Technical Association of the Pulp and Paper Industry."},{"key":"ref_41","first-page":"1","article-title":"Influence of thermal treatment on selected properties of chestnut wood and full range of its visual features","volume":"63","author":"Pelosi","year":"2020","journal-title":"Drewno"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1179\/2042645313Y.0000000056","article-title":"Approach for color homogenisation of chestnut (Castanea sativa [Mill.]) by thermal modification","volume":"5","author":"Wimmer","year":"2014","journal-title":"Int. Wood Prod. J."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"385","DOI":"10.1515\/HF.2009.078","article-title":"Color in thermally modified wood of beech, Norway spruce and Scots pine. Part 1: Color evolution and color changes","volume":"63","author":"Hale","year":"2009","journal-title":"Holzforshung"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"799","DOI":"10.15376\/biores.7.1.799-815","article-title":"Estimation of heat treated wood properties by color change","volume":"7","year":"2012","journal-title":"Bioresources"},{"key":"ref_45","unstructured":"(2015). ASTM E313Standard Practice for Calculating Yellowness and Whiteness Indices from Instrumentally Measured Color Coordinates."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"471","DOI":"10.1016\/j.polymer.2011.12.040","article-title":"Interfacial modification of boron nitride nanoplatelets for epoxy composites with improved thermal properties","volume":"53","author":"Yu","year":"2012","journal-title":"Polymer"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"13","DOI":"10.11118\/actaun201058050013","article-title":"Color of tropical wood and discoloration due to simulated sunlight","volume":"58","author":"Baar","year":"2010","journal-title":"Acta Univ. Agric. Silvic. Mendel. Brun."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1903","DOI":"10.15376\/biores.12.1.1903-1915","article-title":"Thermo-vacuum modification of teak wood from fast-growth plantation","volume":"12","author":"Cuccui","year":"2017","journal-title":"BioResources"},{"key":"ref_49","unstructured":"Sehistedt-Persson, M. (2003, January 25). Color responses to heat-treatment of extractives and sap from pine and spruce. In Proceeding of the International IUFRO Wood Drying Conference, Brasov, Romania."},{"key":"ref_50","unstructured":"Sundqvist, B. (2004). Color Changes and Acid Formation in Wood During. [Ph.D. Thesis, Lule\u00e5 Tekniska Universitet]."},{"key":"ref_51","unstructured":"Polcin, J., and Rapson, W.H. The interpretation of UV and visible spectrum of lignin. In Proceeding of the 55th Annual Meeting of the Technical Section, Montreal, QC, Canada."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"365","DOI":"10.1515\/HF.2006.057","article-title":"The nature of chromophores in high-extractives mechanical pulps: Western red cedar (Thuja plicata Donn) chemithermomechanical pulp (CTMP)","volume":"60","author":"Keating","year":"2006","journal-title":"Holzforschung"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"770","DOI":"10.1016\/j.msea.2010.09.092","article-title":"Effect of heat treatment on microstructure and mechanical properties of high boron white cast iron","volume":"528","author":"Chen","year":"2010","journal-title":"Mater. Sci. Eng."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1016\/j.indcrop.2009.05.008","article-title":"The effect of extraction process on polyphenol content, triterpene composition and bioactivity of yellow birch (Betula alleghaniensis Britton) extracts","volume":"30","author":"Diouf","year":"2009","journal-title":"Ind. Crops Prod."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"539","DOI":"10.1515\/HF.2003.080","article-title":"Effect of high temperature on the change in color, dimensional stability and mechanical properties of spruce wood","volume":"57","author":"Bekhta","year":"2003","journal-title":"Holzforschung"},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"44","DOI":"10.4028\/www.scientific.net\/KEM.688.44","article-title":"The effects of heat treatment on the chemical alterations of oak wood","volume":"688","year":"2016","journal-title":"Key Eng. Mater."},{"key":"ref_57","unstructured":"Hon, D.N.S., and Shiraishi, N. (1991). Wood and Cellulosic Chemistry, Marcel Dekker."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1016\/j.indcrop.2012.04.012","article-title":"Antioxidant activities, total phenolic contents and chemical compositions of extracts from four Cameroonian woods: Padouk (Pterocarpus soyauxii Taubb), tali (Erythrophleum suaveolens), moabi (Baillonella toxisperma), and movingui (Distemonanthus benthamianus)","volume":"41","author":"Saha","year":"2013","journal-title":"Ind. Crops Prod."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"525","DOI":"10.1051\/forest:2006035","article-title":"Antioxidant properties of wood extracts and color stability of woods","volume":"63","author":"Diouf","year":"2006","journal-title":"Ann. For. Sci."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1007\/s001070050088","article-title":"Chemical composition of extractives from Abies nordmanniana","volume":"53","author":"Hafizoglu","year":"1995","journal-title":"Holz Als Roh-Und Werkst."},{"key":"ref_61","unstructured":"Fengel, D., and Wegener, G. (1989). Wood: Chemistry, Ultrastructure, Reactions, Walter De Gruyter."},{"key":"ref_62","unstructured":"Stenius, P. (2000). Forest Products Chemistry, Faper Oy. [3rd ed.]."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1081\/WCT-120035941","article-title":"Thermal modifications in softwood studied by FT-IR and UV resonance Raman spectroscopies","volume":"24","author":"Nuopponen","year":"2005","journal-title":"J. Wood Chem. Technol."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1007\/BF02626519","article-title":"Thermal degradation products of wood. Gas chromatographic separation and mass spectrometric characterization of monomeric lignin-derived products","volume":"48","author":"Faix","year":"1990","journal-title":"Holz Als Roh-Und Werkst."},{"key":"ref_65","unstructured":"\u010cervenka, E., Kr\u00e1l, Z., and Tomis, B. (1980). Chemistry of Wood and Cellulose I\u2013III, The University of Chemical Technology in Pardubice. (In Czech)."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"303","DOI":"10.1016\/j.indcrop.2008.03.006","article-title":"Chemical constituents and physical properties of guayule wood and bark","volume":"28","author":"Chow","year":"2008","journal-title":"Ind. Crops Prod."},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1007\/s00107-003-0389-2","article-title":"Color stability of heat-treated wood during artificial weathering","volume":"61","author":"Ayadi","year":"2003","journal-title":"Holz Als Roh-Und Werkst."},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"6250","DOI":"10.15376\/biores.13.3.6250-6264","article-title":"Predicting Color Change in Wood During Heat Treatment Using an Artificial Neural Network Model","volume":"13","author":"Nguyen","year":"2018","journal-title":"BioResources"},{"key":"ref_69","doi-asserted-by":"crossref","unstructured":"Cirule, D., Sansonetti, E., Andersone, I., Kuka, E., and Andersons, B. (2021). Enhancing Thermally Modified Wood Stability against Discoloration. Coatings, 11.","DOI":"10.3390\/coatings11010081"},{"key":"ref_70","doi-asserted-by":"crossref","first-page":"274","DOI":"10.3390\/oxygen3030018","article-title":"Successive Solvent Extraction of Polyphenols and Flavonoids from Cistus creticus L. Leaves","volume":"3","author":"Palaiogiannis","year":"2023","journal-title":"Oxygen"},{"key":"ref_71","doi-asserted-by":"crossref","unstructured":"Hon, D.N., and Shiraishi, N. (2000). Wood, and Cellulosic Chemistry, Revised, and Expanded, CRC Press. [2nd ed.].","DOI":"10.1201\/9781482269741"},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"102","DOI":"10.1007\/s00107-004-0532-8","article-title":"Chemical changes in hydrothermal treated wood: FTIR analysis of combined hydrothermal and dry heat-treated wood","volume":"63","author":"Tjeerdsma","year":"2005","journal-title":"Eur. J. Wood Wood Prod."},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"889","DOI":"10.3891\/acta.chem.scand.24-0889","article-title":"Acid degradation of lignin","volume":"24","author":"Lundquist","year":"1970","journal-title":"Acta Chem. Scand."},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1007\/s00226-009-0275-0","article-title":"Wood properties of juvenile and mature heartwood in Robinia pseudoacacia L","volume":"44","author":"Richter","year":"2010","journal-title":"Wood Sci. Technol."},{"key":"ref_75","doi-asserted-by":"crossref","first-page":"168","DOI":"10.1515\/hfsg.1995.49.2.168","article-title":"Characterization of European Oakwood Constituents Acting in the Brown Discolouration during Kiln Drying","volume":"49","author":"Charrier","year":"1995","journal-title":"Holzforschung"},{"key":"ref_76","doi-asserted-by":"crossref","first-page":"973","DOI":"10.1007\/s10457-018-0194-x","article-title":"Evaluation of wood properties of four ages of Cedrela odorata trees growing in agroforestry systems with Theobroma cacao in Costa Rica","volume":"93","author":"Tenorio","year":"2019","journal-title":"Agrofor. Syst."},{"key":"ref_77","doi-asserted-by":"crossref","first-page":"1314","DOI":"10.1080\/01694243.2021.1970318","article-title":"Causes of differential behavior of extractives on the natural cold water durability of the welded joints of three tropical woods","volume":"36","author":"Mfomo","year":"2022","journal-title":"J. Adhes. Sci. Technol."},{"key":"ref_78","doi-asserted-by":"crossref","first-page":"103360","DOI":"10.1016\/j.ijadhadh.2023.103360","article-title":"Iroko wood (Milicia excelsa CC berg), a good candidate for high-speed rotation-induced wood dowel welding: An assessment of its welding potential and the water resistance of its welded joints","volume":"123","author":"Mfomo","year":"2023","journal-title":"Int. J. Adhes. Adhes."},{"key":"ref_79","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1007\/s001070050271","article-title":"Effect of the extractives of yellow meranti wood on the manufacture of plywood","volume":"56","author":"Yasuda","year":"1998","journal-title":"Eur. J. Wood Wood Prod."},{"key":"ref_80","doi-asserted-by":"crossref","first-page":"1099","DOI":"10.1016\/0031-9422(80)83063-9","article-title":"Distribution of some triterpenes and phenolic compounds in the extractives of endemic Dipterocarpaceae species of Sri Lanka","volume":"19","author":"Geevananda","year":"1980","journal-title":"Phytochemistry"},{"key":"ref_81","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1007\/s00107-010-0489-8","article-title":"Extractives in some tropical woods","volume":"70","author":"Kilic","year":"2012","journal-title":"Eur. J. Wood Wood Prod."},{"key":"ref_82","doi-asserted-by":"crossref","unstructured":"Malik, J., Santoso, A., and Ozarska, B. (2020, January 1). Polymerised Merbau Extractives as Impregnating Material for Wood Properties Enhancement. In Proceeding of the Materials Science and Engineering, Bogor, Indonesia.","DOI":"10.1088\/1757-899X\/935\/1\/012021"},{"key":"ref_83","unstructured":"Myo Aung, U. (1988). A Preliminary Study of Anthraquinone Extractives in Teak. Leaflet No. 8\/87-88, Forest Research Institute."},{"key":"ref_84","unstructured":"Simatupang, M.H., and Yamamoto, K. (1999, January 26\u201329). Properties of teakwood (Tectona grandis L.f.) as influenced by wood extractives and its importance for tree breeding. Proceedings of the Regional Seminar on Site, Technology and Productivity od Teak Plantations, Chiang Mai, Thailand."},{"key":"ref_85","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1007\/s00107-006-0127-7","article-title":"Chemical extractive compounds determining the brown-rot decay resistance of teak wood","volume":"65","author":"Bhat","year":"2007","journal-title":"Holz Als Roh-Und Werkst."}],"container-title":["Polymers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4360\/15\/19\/4000\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T21:01:40Z","timestamp":1760130100000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4360\/15\/19\/4000"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,10,5]]},"references-count":85,"journal-issue":{"issue":"19","published-online":{"date-parts":[[2023,10]]}},"alternative-id":["polym15194000"],"URL":"https:\/\/doi.org\/10.3390\/polym15194000","relation":{},"ISSN":["2073-4360"],"issn-type":[{"value":"2073-4360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,10,5]]}}}