Accessible Unlicensed Requires Authentication Published by De Gruyter July 27, 2020

Comparison of silicate impregnation methods to reinforce Chinese fir wood

Ping Li, Yuan Zhang, Yingfeng Zuo, Yiqiang Wu, Guangming Yuan and Jianxiong Lu
From the journal Holzforschung


Inorganic impregnation strengthening of Chinese fir wood was carried out to improve the strength, dimensional stability, flame retardancy, and smoke suppression of Chinese fir wood. Sodium silicate was used as reinforcement, a sulfate and phosphate mixtures were used as a curing agent, and Chinese fir wood was reinforced by the respiratory impregnation method (RIM) that imitating human respiration and vacuum progressive impregnation method (VPIM). The weight percentage gain (WPG), density increase rate, distribution of modifier, bending strength (BS), compressive strength (CS), hardness, and water resistance of unreinforced Chinese fir wood from the VPIM and RIM were compared. It was found that RIM could effectively open the aspirated pits in Chinese fir wood, so its impregnation effect, strengthen effect and dimension stabilization effects were the best. RIM-reinforced Chinese fir wood was filled with silicate both horizontally and vertically. At the same time, the transverse permeability of silicate through aspirated pits was significantly improved. The chemical structure, crystalline structure, flame retardancy, smoke suppression, and thermal stability of VPIM- and RIM-reinforced Chinese fir wood were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), cone calorimeter (CONE), and thermogravimetric analysis (TGA). The results indicated that although the crystallinity of RIM-reinforced Chinese fir wood decreased the most, more chemical crosslinking and hydrogen bonding were formed in the wood, and the strengthen effect was still the best. Compared with VPIM-reinforced Chinese fir wood, RIM-reinforced Chinese fir wood had lower heat release rate (HRR), peak-HRR, mean-HRR, total heat release (THR), smoke production rate (SPR), and total smoke production (TSP), higher thermal decomposition temperature and residual rate. It was indicated that RIM-reinforced Chinese fir wood was a better flame retardant, and has a smoke suppression effect, thermal stability, and safety performance in the case of fire.

Corresponding authors: Yingfeng Zuo, College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan, 410004, PR China, E-mail: ; and Jianxiong Lu, College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan, 410004, PR China; and Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing, 100091, PR China, E-mail:

Funding source: Key Laboratory of Bio-based Material Science & Technology (Northeast Forestry University) Ministry of Education of the People's Republic of China

Award Identifier / Grant number: SWZ-MS201917

Funding source: Hunan Provincial Technical Innovation Platform Talent Program in Science and Technology

Award Identifier / Grant number: 2019RS2040

Funding source: Major Science and Technology Program of Hunan Province

Award Identifier / Grant number: 2017NK1010

Funding source: National Natural Science Foundation of China

Award Identifier / Grant number: 31770606

Funding source: Hunan Province Innovation Foundation for Postgraduate

Award Identifier / Grant number: CX20190600

Funding source: Central South Forestry University of Science and Technology

Award Identifier / Grant number: CX20191010, CX20192003

  1. Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

  2. Research funding: This research was supported by the Key Laboratory of Bio-based Material Science & Technology (Northeast Forestry University), Ministry of Education of the People’s Republic of China (SWZ-MS201917), Hunan Provincial Technical Innovation Platform and Talent Program in Science and Technology, PR China (2019RS2040), Major Science and Technology Program of Hunan Province, PR China (2017NK1010), National Natural Science Foundation of China (31770606), Hunan Province Innovation Foundation for Postgraduate, PR China (CX20190600) and Science and Technology Innovation Project for Postgraduates of Central South Forestry University of Science and Technology, PR China (CX20191010, CX20192003).

  3. Conflict of interest statement: The authors declare no conflicts of interest.


Alexandre, M. and Dubois, P. (2000). Polymer-layered silicate nanocomposites: preparation, properties and uses of a new class of materials. Mat. Sci. Eng. R. 28: 1–63. Search in Google Scholar

Aydemir, D., Kiziltas, A., Kiziltas, E.E., Gardner, D.J., and Gunduz, G. (2015). Heat treated wood–nylon 6 composites. Compos. Part B-Eng. 68: 414–423. Search in Google Scholar

Baysal, E. and Yalinkilic, M.K. (2005). A new boron impregnation technique of wood by vapor boron of boric acid to reduce leaching boron from wood. Wood Sci. Technol. 39: 187–198. Search in Google Scholar

Bednarek, Z. and Kaliszuk-Wietecka, A. (2007). Analysis of the fire-protection impregnation influence on wood strength. J. Civ. Eng. Manag. 13: 79–85. Search in Google Scholar

Chang, H.T. and Chang, S.T. (2006). Modification of wood with isopropyl glycidyl ether and its effects on decay resistance and light stability. Bioresource Technol. 97: 1265–1271. Search in Google Scholar

Croitoru, C., Patachia, S., and Lunguleasa, A. (2015). New method of wood impregnation with inorganic compounds using ethyl methylimidazolium chloride as carrier. J. Wood Chem. Technol. 35: 113–128. Search in Google Scholar

Dong, Y., Zhang, S., and Li, J. (2017). Research progress in wood cell wall modification. J. Forest. Eng. 2: 34–39. Search in Google Scholar

Esteves, B. and Pereira, H. (2009). Wood modification by heat treatment: A review. BioResources 4: 370–404. Search in Google Scholar

Fernandes, J., Kjellow, A.W., and Henriksen, O. (2012). Modeling and optimization of the supercritical wood impregnation process-focus on pressure and temperature. J. Supercrit. Fluid. 66: 307–314. Search in Google Scholar

Grexa, O. and Lübke, H. (2001). Flammability parameters of wood tested on a cone calorimeter. Polym. Degrad. Stabil. 74: 427–432. Search in Google Scholar

He, G., Riedl, B., and Ait-Kadi, A. (2003). Curing process of powdered phenol-formaldehyde resol resins and the role of water in the curing system. J. Appl. Polym. Sci. 89: 1371–1378. Search in Google Scholar

He, G., Riedl, B., and Aït-Kadi, A. (2003). Model-free kinetics: curing behavior of phenol formaldehyde resins by differential scanning calorimetry. J. Appl. Polym. Sci. 87: 433–440. Search in Google Scholar

He, S., Lin, L., Fu, F., Zhou, Y., and Fan, M. (2014). Microwave treatment for enhancing the liquid permeability of Chinese fir. BioResources. 9: 1924–1938. Search in Google Scholar

Huang, Y., Fei, B., Yu, Y., and Zhao, R. (2012). Effect of modification with phenol formaldehyde resin on the mechanical properties of wood from Chinese fir. BioResources. 8: 272–282. Search in Google Scholar

Lee, W.J. and Lan, W.C. (2006). Properties of resorcinol–tannin–formaldehyde copolymer resins prepared from the bark extracts of Taiwan acacia and China fir. Bioresource Technol. 97: 257–264. Search in Google Scholar

Locs, J., Berzina-Cimdina, L., Zhurinsh, A., and Loca, D. (2009). Optimized vacuum/pressure sol impregnation processing of wood for the synthesis of porous, biomorphic SiC ceramics. J. Eur. Ceram. Soc. 29: 1513–1519. Search in Google Scholar

Lou, Z., Han, H., Zhou, M., Han, J., Cai, J., Huang, C., Zou, J., Zhou, X., Zhou, H., and Sun, Z. (2018). Synthesis of magnetic wood with excellent and tunable electromagnetic wave-absorbing properties by a facile vacuum/pressure impregnation method. ACS Sustain. Chem. Eng. 6: 1000–1008. Search in Google Scholar

Lu, J., Lin, Z., Jiang, J., and Jiang, J. (2005). Liquid penetration of freeze-drying and air-drying wood of plantation Chinese fir. J. Forestry Res. 16: 293–295. Search in Google Scholar

Lu, Y., Feng, M., and Zhan, H. (2014). Preparation of SiO2-wood composites by an ultrasonic-assisted sol-gel technique. Cellulose. 21: 4393–4403. Search in Google Scholar

Mai, C. and Militz, H. (2004). Modification of wood with silicon compounds. Inorganic silicon compounds and sol-gel systems: a review. Wood Sci. Technol. 37: 339–348. Search in Google Scholar

Pérez, J., Munoz-Dorado, J., De la Rubia, T., and Martínez, J. (2002). Biodegradation and biological treatments of cellulose, hemicellulose and lignin: an overview. Int. Microbiol. 5: 53–63. Search in Google Scholar

Samal, R., Rana, P.K., Mishra, G.P., and Sahoo, P.K. (2008). Novel biodegradable flame retardant, poly (butyl methacrylate)/sodium silicate/Mg(OH)2 nanocomposite. Polym. Composite. 29: 173–178. Search in Google Scholar

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

Shi, Z., Fu, F., Wang, S., He, S., and Yang, R. (2013). Modification of Chinese fir with alkyl ketene dimer (AKD): processing and characterization. BioResources 8: 581–591. Search in Google Scholar

Toba, K., Yamamoto, H., and Yoshida, M. (2013). Crystallization of cellulose microfibrils in wood cell wall by repeated dry-and-wet treatment, using X-ray diffraction technique. Cellulose 20: 633–643. Search in Google Scholar

Wang, X., Liu, J., and Chai, Y. (2012). Thermal, mechanical, and moisture absorption properties of wood-TiO2 composites prepared by a sol-gel process. BioResources 7: 893–901. Search in Google Scholar

Wang, F., Liu, J., and Lu, W. (2017). Thermal degradation and fire performance of wood treated with PMUF resin and boron compounds. Fire Mater. 41: 1051–1057. Search in Google Scholar

Yao, M., Yang, Y., Song, J., Yu, Y., and Jin, Y. (2017). Lignin-based catalysts for Chinese fir furfurylation to improve dimensional stability and mechanical properties. Ind. Crops Prod. 107: 38–44. Search in Google Scholar

Yuan, L., Chen, X., and Hu, Y. (2014). Combination effect of 4-picolinic acid with 5A zeolite on ammonium polyphosphate flame-retarded sawdust board. J. Fire Sci. 32: 230–240. Search in Google Scholar

Yue, K., Chen, Z., Lu, W., Liu, W., Li, M., Shao, Y., Tang, L., and Wan, L. (2017). Evaluating the mechanical and fire-resistance properties of reinforced fast-growing Chinese fir timber with boric-phenol-formaldehyde resin. Constr. Build. Mater. 154: 956–962. Search in Google Scholar

Received: 2020-01-15
Accepted: 2020-03-24
Published Online: 2020-07-27
Published in Print: 2021-02-23

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