Journal of Wood Science

, Volume 47, Issue 6, pp 483–489 | Cite as

Na2O-SiO2 wood-inorganic composites prepared by the sol-gel process and their fire-resistant properties

  • Hisashi MiyafujiEmail author
  • Shiro Saka
Original Article


For enhancing fire-resistant properties, a binary system to prepare wood-inorganic composites was studied by adding sodium methoxide (SM) or sodium acetate (SA) to a reaction system for SiO2 composites. Compared with the SiO2 composites, both the Na2O-SiO2 composites prepared could be greatly improved up to 600°C-700°C (glowing). From scanning electron microscopic observations, this enhanced fire resistance was assumed to be due to chemical and physicochemical effects, such as dehydration and carbonization of wood by Na2O gel. The glassy layer and intumescent structure formed over the cell walls were thought to prevent oxidation and heat transfer from proceeding into the inner portion of the wood cell walls. However, the reaction medium with SM to prepare Na2O-SiO2 composites was basic, whereas that with SA was rather neutral. In addition, in the latter composites, most of the inorganic gel was formed within the cell wall, retaining the porous structure characteristic of wood. Therefore, the Na2O-SiO2 composites prepared with SA can be concluded to be preferable for practical purposes.

Key words

Wood-inorganic composites Sol-gel process Na2O-SiO2 Thermal analysis Fire resistance 


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Copyright information

© The Japan Wood Research Society 2001

Authors and Affiliations

  1. 1.Department of Socio-Environmental Energy Science, Graduate School of Energy ScienceKyoto UniversityKyotoJapan

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