Skip to content
Licensed Unlicensed Requires Authentication Published by De Gruyter August 28, 2013

Evaluation of the effects of compression combined with heat treatment by nanoindentation (NI) of poplar cell walls

  • Xinzhou Wang , Yuhe Deng EMAIL logo , Siqun Wang , Chen Min , Yujie Meng , Tuonglam Pham and Yang Ying
From the journal Holzforschung


A combination of compression and heat treatment is a modification method that has great potential for improving the mechanical properties and dimensional stability of wood materials in industrial application. The objective of this project was to track changes in the microstructure, chemical composition, cellulose crystallinity, and mechanical properties of the treated poplar cell wall to investigate the mechanism of modification. Poplar boards were compressed at 100°C and subsequently treated in the hot press at 200°C. The results indicated that the treatment contributed to a reduction in porosity without obvious mechanical compression and damage to the cell wall. Hemicellulose degraded, however, and the relative lignin content and cellulose crystallinity increased during the process. The observed increase in relative lignin content and crystallinity may contribute to the improvement of mechanical properties. The longitudinal elastic modulus and hardness of poplar cell walls increased significantly from 12.5 and 0.39 GPa for the control to a maximum of 15.7 and 0.51 GPa for compressed wood with HT, respectively.

Corresponding author: Yuhe Deng, College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, P.R. China, Fax: +86-25-85427653, e-mail:

The authors gratefully acknowledge the financial supported by the Doctorate Fellowship Foundation of Nanjing Forestry University, A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, and Jiangsu Province Graduate Education Innovation Project (CXLX13_527).


Almeida, G., Brito, J.O., Perré, P. (2009) Changes in wood-water relationship due to heat treatment assessed on micro-samples of three Eucalyptus species. Holzforschung 63:80–88.10.1515/HF.2009.026Search in Google Scholar

Assaf, A.G., Haas, R.H., Purves C.B. (1944) A study of the amorphous portion of dry, swollen cellulose by an improved thallous ethylate method. J. Am. Chem. Soc. 66:59–65.Search in Google Scholar

Avila, C.B., Escobar, W.G., Cloutier, A., Fang, C.H., Carrasco, P.V. (2012) Densification of wood veneers combined with oil-heat treatment. Part III: cell wall mechanical properties determined by nanoindentation. BioResources 7:1525–1532.Search in Google Scholar

Bami, L.K., Mohebby, B. (2011) Bioresistance of poplar wood compressed by combined hydro-thermo-mechanical wood modification (CHTM): soft rot and brown-rot. Int. Biodeterior. Biodegrad. 65:866–870.Search in Google Scholar

Bhuiyan, M.T.R., Nobuyuki, H., Nobuo, S. (2000) Changes of crystallinity in wood cellulose by heat treatment under dried and moist conditions. J. Wood Sci. 46:431–436.10.1007/BF00765800Search in Google Scholar

Boonstra, M.J., Blomberg, J. (2007) Semi-isostatic densification of heat-treated radiata pine. Wood Sci. Technol. 41:607–617.Search in Google Scholar

Boonstra, M., Tjeerdsma, B. (2006) Chemical analysis of heat treated softwoods. Holz Roh Werkst. 64:204–211.10.1007/s00107-005-0078-4Search in Google Scholar

Chen, C., Deng, Y.H., Xu, L., Chen, M., Wang, X.Z. (2012) Compressed and carbonized poplar panel for parquet. China Wood-Based Panels 3:20–23.Search in Google Scholar

Chinese Standard (1994) GB/T 2677.8-1994, China State Administration of Quality Supervision Inspection and Quarantine. Fibrous raw material — determination of acid-insoluble lignin.Search in Google Scholar

De Boever, L., Vansteenkiste, D., Van Acker, J., Stevens, M. (2007) End-use related physical and mechanical properties of selected fast-growing poplar hybrids (Populus trichocarpa × P. deltoides). Ann. For. Sci. 64 621–630.Search in Google Scholar

Diouf, P.N., Stevanovic, T., Cloutuer, A., Fang, C.H., Blanchet, P., Koubaa, A., Mariotti, N. (2011) Effects of thermo-hygro-mechanical densification on the surface characteristics of trembling aspen and hybrid poplar wood veneers. Appl. Surf. Sci. 257:3558–3564.Search in Google Scholar

Donath, S., Militz, H., Mai, C. (2006) Creating water-repellent effects on wood by treatment with silanes. Holzforschung 60:40–46.10.1515/HF.2006.008Search in Google Scholar

Dubey, M.K., Pang, S., Walker, J. (2011) Changes in chemistry, color, dimensional stability and fungal resistance of Pinus radiate D. Don wood with oil heat-treatment. Holzforschung 66:49–57.Search in Google Scholar

Dwainto, W., Inoue, M., Norimoto, M. (1997) Fixation of deformation of wood by heat treatment. Makuzai Gakkaishi 43:303–309.Search in Google Scholar

Esteves, B., Graça, J., Pereira, H. (2008) Extractive composition and summative chemical analysis of thermally treated eucalypt wood. Holzforschung 62:344–351.10.1515/HF.2008.057Search in Google Scholar

Fang, C.H., Cloutier, A., Blanchet, P., Koubaa, A., Mariotti, N. (2011) Densification of wood veneers combined with oil-heat treatment. Part I: dimensional stability. BioResoures 6:373–385.10.15376/biores.6.1.373-385Search in Google Scholar

Fukuta, S., Asada, F., Sasaki, Y. (2008) The simultaneous treatment of compression drying and deformation fixation in the compression processing of wood. For. Prod. J. 58:82–88.Search in Google Scholar

Gabrielli, C.P., Kamke, F.A. (2010) Phenol-formaldehyde impregnation of densified wood for improved dimensional stability. Wood Sci. Technol. 44:95–104.Search in Google Scholar

Gindl, W., Gupta, H.S., Grunwald, C. (2002) Lignification of spruce tracheids secondary cell wall related to longitudinal hardness and modulus of elasticity using nano-indentation. Can. J. Bot. 80:1029–1033.Search in Google Scholar

Gonzalez-Pena, M.M., Curling, S.F., Hale, M.D.C. (2009) On the effect of heat on the chemical composition and dimensions of thermally-modified wood. Polym. Degrad. Stab. 94:2184–2193.10.1016/j.polymdegradstab.2009.09.003Search in Google Scholar

Heger, F., Giroux, M., Girardet, F., Welzbacher, C., Rapp, A.O., Navi, P. (2004) Mechanical and durability performance of THM-densified wood. In: Final Workshop Cost Action, Environmental Optimization of Wood Protection, Lisbon, Portugal. Hamburg: Bundesforschungsanst. Forst- Holzwirtsch. pp. 1–10.Search in Google Scholar

Inoue, M., Sekino, N., Morooka, T., Rowell, R.M., Norimoto, M. (2008) Fixation of compressive deformation in wood by pre-steaming. J. Trop. For. Sci. 20:273–281.Search in Google Scholar

Kollmann, F.P., Kuenzi, E.W., Stamm, A.J. (1975) Principles of Wood Science and Technology. Vol. II: Wood Based Materials. Springer-Verlag, New York/Heidelberg/Berlin. pp. 139–149.10.1007/978-3-642-87931-9Search in Google Scholar

Kotilainen, R. Chemical changes in wood during heating at 150–260°C. Ph.D. thesis, Jyvaskyla University. Research Report 80, Finland, 2000.Search in Google Scholar

Lee, C.L. (1961) Crystallinity of wood cellulose fibers studies by X-ray methods. For. Prod. J. 11:108–112.Search in Google Scholar

Li, X.P., Wang, S.Q., Du, G.B., Wu, Z.K., Meng, Y.J. (2013) Variation in physical and mechanical properties of hemp stalk fibers along height of stem. Ind. Crops Prod. 42:344–348.10.1016/j.indcrop.2012.05.043Search in Google Scholar

Liu, C.K., Lee, S., Sung, L.P., Nguyen, T. (2006) Load-displacement relations for nano-indentation of viscoelastic materials. J. Appl. Phys. 100:033503–033511.Search in Google Scholar

Manninen, A.M., Pasanen, P., Holopainen, J.K. (2002) Comparing the VOC emissions between air-dried and heat-treated Scots pine wood. Atmos. Environ. 36:1763–1768.Search in Google Scholar

Morsing, N. (2000) Densification of wood—the influence of hygrothermal treatment on compression of beech perpendicular to the grain. Department of Structural engineering and Materials, Technical University of Denmark, Series R, 79, 138 pp.Search in Google Scholar

Navi, P., Heger, F. (2004) Combined densification and thermo-hydro-mechanical processing of wood. MRS Bull. 29:332–336.10.1557/mrs2004.100Search in Google Scholar

Oliver, W.C., Pharr, G.M. (1992) An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. J. Mater. Res. 7:1564–1583.Search in Google Scholar

Pfriem, A., Dietrich, T., Buchelt, B. (2012) Furfuryl alcohol impregnation for improved plasticization and fixation during the densification of wood. Holzforschung 66:215–218.10.1515/HF.2011.134Search in Google Scholar

Segal, L., Creely, J.J., Martin, Jr., A.E., Conrad, C.M. (1959) An empirical method for estimating the degree of crystallinity of native cellulose using the X-ray diffractometer. Textile Res. J. 29:786–794.Search in Google Scholar

Stanzl-Tschegg, S., Beikircher, W., Loidl, D. (2009) Comparison of mechanical properties of thermally modified wood at growth ring and cell wall level by means of instrumented indentation tests. Holzforschung 63:443–448.10.1515/HF.2009.085Search in Google Scholar

Tanahashi, M., Goto, T., Horii, F., Hirai, A., Higichi, T. (1989) Characterization of steam-exploded wood. III. Transformation of cellulose crystals and changes of crystallinity. Mokuzai Gakkaishi 35:654–662.Search in Google Scholar

Tuong, V.M., Li, J. (2011) Changes caused by heat treatment in chemical composition and some physical properties of acacia hybrid sapwood. Holzforschung 65:67–72.10.1515/hf.2010.118Search in Google Scholar

Vukusic, S.B., Katovic, D., Schramm, C., Trajkovic, J., Sefc, B. (2006) Polycarboxylic acids as non-formaldehyde anti-swelling agents for wood. Holzforschung 60:439–444.10.1515/HF.2006.069Search in Google Scholar

Wang, X.Z., Deng Y.H., Wang, S.Q., Meng, Y.J., Liao, C.B., Pham, T.L. (2013) Nanoscale characterization of reed stalk fiber cell walls. Bioresources 8:1986–1996.10.15376/biores.8.2.1986-1996Search in Google Scholar

Windeisen, E., Bachle, H., Zimmer, B., Wegener, G. (2009) Relations between chemical changes and mechanical properties of thermally treated wood. Holzforschung 63:773–778.Search in Google Scholar

Xing, C., Wang, S.Q., Pharr, G.M., Groom, L.H. (2008) Effect of thermo-mechanical refining pressure on the properties of wood fibers as measured by nanoindentation and atomic force microscopy. Holzforschung 62:230–236.10.1515/HF.2008.050Search in Google Scholar

Yildiz, S., Gezer, E.D., Yildiz, U.C. (2006) Mechanical and chemical behavior of spruce wood modified by heat. Build. Environ. 41:1762–1766.Search in Google Scholar

Yu, Yan., Fei, B.H., Wang, H.K., Tian, G.L. (2011) Longitudinal mechanical properties of cell wall of Masson pine (Pinus massoniana Lamb) as related to moisture content: a nanoindentation study. Holzforschung 65:121–126.10.1515/hf.2011.014Search in Google Scholar

Zaman, A., Alen, R., Kotilainen, R. (2000) Thermal behavior of Scots pine (Pinus sylvestris) and silver birch (Betula pendula) at 200–230°C. Wood Fiber Sci. 32:138–143.Search in Google Scholar

Received: 2013-5-11
Accepted: 2013-8-2
Published Online: 2013-08-28
Published in Print: 2014-02-01

©2014 by Walter de Gruyter Berlin Boston

Downloaded on 8.12.2023 from
Scroll to top button