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Effects of preboiling on the acidity and strength properties of heat-treated wood

Wood Science and Technology volume 43, pages 97–103 (2009)Cite this article

Abstract

Heat treatment is an alternative to the chemical treatment in wood preservation, which has been used to some extent in improving timber quality. However, reduction in strength properties has been one of the major limitations in the use of this technique and therefore investigations on the use of various pre-treatment methods are highly essential. Wood samples from Scots pine were immersed in already boiling water (100°C) for 20 min followed by 2 h of heat treatment at 160 and 200°C. The acidity and strength properties were determined by measurement of pH and static bending test, respectively. There were no significant changes in pH due to preboiling in both heat-treated and untreated wood. Similarly, preboiling did not result in any appreciable differences in strength both before heat treatment and during heat treatment at 160°C. However, for 200°C heat treatment preboiling reduced significantly the degree of strength loss as indicated by 19.4% reduction in modulus of rupture in preboiled wood compared to 26.6% reduction in unpreboiled wood. From the results of this study it is evident that preboiling has a buffering effect on wood during heat treatment and the higher the intensity of heat treatment the higher the significance of the buffering effect of pre-boiling.

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References

  • Awoyemi L, Westermark U (2005) Effects of borate impregnation on the response of wood strength to heat treatment. Wood Sci Technol 39:484–491

    CAS  Google Scholar 

  • Ayadi N, Lejeune F, Charrier F, Charrier B, Merlin A (2003) Colour stability of heat-treated wood during artificial weathering. Holz Roh Werkst 61:221–226

    CAS  Google Scholar 

  • Boonstra MJ, Tjeerdsma B (2006) Chemical analysis of heat treated softwoods. Holz Roh Werkst 64:204–211

    Article  CAS  Google Scholar 

  • Boonstra MJ, van Acker J, Kegel E, Stevens M (2006) Optimisation of a two stage heat treatment process: durability aspects. Wood Sci Technol 40:31–57

    Google Scholar 

  • Chafe SC (1993) The effect of boiling on shrinkage, collapse and other wood–water properties in core segments of Eucalyptus regnans F. Muell. Wood Sci Technol 27:205–217

    CAS  Google Scholar 

  • Geissen A, Du QP (1995) Influence of heat treatment on the accuracy of wood moisture content determination by electrical resistance-type meters. Holz Roh Werkst 53:303–307

    CAS  Google Scholar 

  • Hakkou M, Petrissans M, Zoulalian A, Gerardin P (2005) Investigation of wood wettability changes during heat treatment on the basis of chemical analysis. Polym Degrad Stab 89:1–5

    Article  CAS  Google Scholar 

  • Hanger J, Huber H, Lackner R, Wimmer R, Fellner J (2002) Improving the natural durability of heat-treated spruce, pine and beech. Holzforsch Holzverwert 54:92–93

    CAS  Google Scholar 

  • Hodgin DA, Lee AWC (2002) Comparison of strength properties and failure characteristics between fire-retardant-treated and untreated roofing lumber after long-term exposure: A South Carolina case study. For Prod J 52:91–94

    CAS  Google Scholar 

  • Kamdem DP, Pizzi A, Triboulot MC (2000) Heat-treated timber: potentially toxic byproducts presence and extent of wood cell wall degradation. Holz Roh Werkst 58:253–257

    CAS  Google Scholar 

  • Kamdem DP, Pizzi A, Jermannaud A (2002) Durability of heat-treated wood. Holz Roh Werkst 60:1–6

    CAS  Google Scholar 

  • Kubojima Y, Okano T, Ohta M (2000) Bending strength and toughness of heattreated wood. J Wood Sci 46:8–15

    Google Scholar 

  • Manninen AM, Pasanen P, Holopainen JK (2002) Comparing the VOC emissions between air-dried and heat-treated Scots pine wood. Atmos Environ 36:1763–1768

    CAS  Google Scholar 

  • Metsa-Kortelainen S, Antikainen T, Viitanieni P (2006) The water absorption of sapwood and heartwood of Scots pine and Norway spruce heat-treated at 170°C, 190°C, 210°C and 230°C. Holz Roh Werkst 64:192–197

    Google Scholar 

  • Mitsui K (2006) Changes in colour of spruce by repetitive treatment of light irradiation and heat treatment. Holz Roh- Werkst 64:243–244

    Google Scholar 

  • Nuopponen M, Wikberg H, Vuorinen T, Maunu SL, Jamsa S, Viitaniemi P (2004) Heat-treated softwood exposed to weathering. J Appl Polym Sci 91:2128–2134

    CAS  Google Scholar 

  • Obataya E, Tomita B (2002) Hygroscopicity of heat-treated wood. II. Reversible and irreversible reductions in the hygroscopicity of wood due to heating. Mokuzai Gakkaishi 48:288–295

    CAS  Google Scholar 

  • Obataya E, Tanaka F, Norimoto M, Tomita B (2000) Hygroscopicity of heat treated wood. I. Effects of after-treatments on the hygroscopicity of heat-treated wood. Mokuzai Gakkaishi 46:77–87

    CAS  Google Scholar 

  • Rapp AO, Sailer M (2001) Oil-heat-treatment of wood-process and properties. Drvna Industrija 52:63–70

    Google Scholar 

  • Sailer M, Rapp AO, Leithoff H, Peek RD (2000) Upgrading of wood by application of an oil-heat treatment. Holz Roh Werkst 58:15–22

    CAS  Google Scholar 

  • Tejada A, Okuyama T, Yamamoto H, Yoshida M (1997) Reduction of growth stresses in log by direct heat treatment: assessment of a commercial scale operation. For Prod J 47:86–93

    Google Scholar 

  • Udaka E, Furuno T (2003) Change in crystalline structure of compressed wood by treatment with a closed heating system. Mokuzai Gakkaishi 49:1–6

    CAS  Google Scholar 

Download references

Acknowledgment

The authors gratefully acknowledge the financial support from the University of Glasgow, UK for funding the research visit of the principal author.

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Authors and Affiliations

  1. Department of Forestry, Wildlife and Fisheries, University of Ado Ekiti, Ado Ekiti, Nigeria

    L. Awoyemi

  2. Centre for Timber Engineering, Napier University, Edinburgh, UK

    A. Hapca

  3. Department of Chemistry, University of Glasgow, Glasgow, UK

    M. C. Jarvis

Authors
  1. L. Awoyemi
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  2. M. C. Jarvis
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  3. A. Hapca
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Correspondence to L. Awoyemi.

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Awoyemi, L., Jarvis, M.C. & Hapca, A. Effects of preboiling on the acidity and strength properties of heat-treated wood. Wood Sci Technol 43, 97–103 (2009). https://doi.org/10.1007/s00226-008-0231-4

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  • DOI: https://doi.org/10.1007/s00226-008-0231-4

Keywords

  • Heat Treatment
  • Strength Property
  • Wood Sample
  • Natural Weathering
  • Wood Preservation