Abstract
In order to utilize the plantation poplar wood, white poplar boards were soaked, heated and compressed to improve the mechanical properties in this study. The densities and densified zones were managed inside the board by choosing various parameters of soaking time between 0.5 and 5.5 h, heating time between 20 and 200 s and pressing time between 6 and 60 s. The density gradient was generated with the higher density near surface and the lower density toward the center of board. With this method, the density near the surface can be modified to 0.89 g/cm3 with an increase of about 100 % in comparison with poplar wood without any treatment. The boundary between the high-density layer and the low-density layer was characterized by X-ray scanned images. The modulus of elasticity (MOE) of compressed white poplar wood increased linearly with the compression ratio, and the modulus of rupture (MOR) increased exponentially. At the compression ratio of 47 %, MOE and MOR of compressed poplar wood were 19.77 GPa and 153.94 MPa, respectively. They were 73.2 and 88.9 %, respectively, greater than that of untreated specimens.
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References
Cheng JQ, Yang JJ, Liu P (1992) Handbook of Chinese wood. China Forestry Publishing House, Beijing, pp 576–577
Diouf PN, Stevanovic T, Cloutier A, Fang CH, Blanchet P (2011) Effects of thermo-hygro-mechanical densification on the surface characteristics of trembling Aspen and hybrid Poplar wood veneers. Appl Surf Sci 257(8):3558–3564
Furuta Y, Nakajima M, Nakanii E, Ohkoshi M (2010) The effects of lignin and hemicelluloses on thermal-softening properties of water-swollen wood. Mokuzai Gakkaishi 56(3):132–138
Gabrielli C, Kamke F (2010) Phenol–formaldehyde impregnation of densified wood for improved dimensional stability. Wood Sci Technol 44(1):95–104
He HK, Li XD, Chang JM, Guo XY (2008) Test on the main mechanical properties of hardened fast-growing poplar wood. J Northwest A&F Univ 36(7):155–159
Hillis WE, Rozsa AN (1978) The softening temperatures of wood. Holzforschung 32(2):68–73
Huang RF, Wang YW, Lu JX, Zhang YM, Zhao YK (2012) Sandwich compression of wood by hygro-thermal control. Mokuzai Gakkaishi 58(2):84–89
Inoue M (2002) Current situation and future prospects of compression wood. Wood-Based Panels 9:3–5
Inoue M, Norimoto M (1990) Surface compression of coniferous wood lumber 1: a new technique to compress the surface-layer. Mokuzai Gakkaishi 36(11):969–975
Inoue M, Misato Norimoto, Tanahashi M, Rowell RM (1993a) Steam or heat fixation of compressed wood. Wood Fiber Sci 25(3):224–235
Inoue M, Ogata S, Kawai S, Kawai S, Rowell RM, Norimoto M (1993b) Fixation of compressed wood using melamine-formaldehyde resin. Wood Fiber Sci 25(4):404–410
Johdai S, Sameshima K (1996) Wood science series 4. Kaiseisha-Press, Ootu, Japan, pp 116–119
Kitamori A, Jung KH, Mori T, Komatsu K (2010) Mechanical properties of compressed wood in accordance with the compression ratio. Mokuzai Gakkaishi 56(2):67–78
Kollmann FP, Kuenzi EW, Stamm AJ (1975) Principles of wood science and technology Vol. II: wood based materials. Springer, Heidelberg
Kollmann FP, Kuenzi EW, Stamm AJ (1975b) Principles of wood science and technology Vol. II: wood based materials. Springer, Heidelberg
Kutnar A, Kamke FA (2012) Compression of wood under saturated steam, superheated steam, and transient conditions at 150 °C, 160 °C, and 170 °C. Wood Sci Technol 46:73–88
Li J (1997) Bentwood process of steaming to soften mechanism. Furniture 4:1–4
Liu JL (2000) Study on compressive orthopaedy wood by steam treating at high temperature (I): structure change and dimension stability. J Northeast For Univ 28(4):9–12
Liu HW (2011) Mechanics of materials. Higher Education Press, Beijing, pp 121–122
Liu YX, Zhao GJ (2004) Wood resource materials science. China Forestry Publishing House, Beijing, pp 152–154
Morsing N (2000) Densification of wood—the influence of hygrothermal treatment on compression of beech perpendicular to the grain. Series R, vol 79, Technical University of Denmark, Lyngby, Copenhagen
Norimoto W, Dwianto M, Morooka T, Tanaka F, Inoue M, Liu Y (1998) Radial compression of Sugi wood (Cryptomeria Japonica D. Don). Holzforschung 56(2):403–411
Takahashi A, Nakayama Y (1995) Wood science series 3. Kaiseisha-Press, Ootu, Japan, pp 36–37
Uhmeier A, Morooka T, Norimoto M (1998) Influence of thermal softening and degradation on the radial compression behavior of wet spruce. Holzforschung 52(1):77–81
Wang YW, Huang RF, Zhang YM (2012) Surface densification and heat fixation of Chinese poplar by hydro-thermal control. China Wood Ind 26(2):18–21
Xia J, Huang RF, Lu JX, Zhang YM, Zhao YK (2013) Effect of hydro-thermal pretreatment on compression layer formation during densification of Chinese white poplar. China Wood Ind 27(4):42–45
Yu CM (2011) Numerical analysis of heat and mass transfer for porous materials. Tsinghua University Press, Beijing, pp 235–237
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The authors acknowledge the financial support from the special Scientific Research of the Forest Public Welfare Industry (Grant No. 201404501).
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Gao, Z., Huang, R., Lu, J. et al. Sandwich compression of wood: control of creating density gradient on lumber thickness and properties of compressed wood. Wood Sci Technol 50, 833–844 (2016). https://doi.org/10.1007/s00226-016-0824-2
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DOI: https://doi.org/10.1007/s00226-016-0824-2