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Impregnation of Norway spruce (Picea abies L. Karst.) wood with hydrophobic oil

Ulvcrona, Thomas (2006). Impregnation of Norway spruce (Picea abies L. Karst.) wood with hydrophobic oil. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2006:88
ISBN 91-576-7137-0
[Doctoral thesis]

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The overall goal of this thesis was to develop new knowledge to facilitate the production of Norway spruce wood-based materials that are more durable and more homogenous than current materials by using a hydrophobic oil impregnation process). Linseed oil uptake and its dispersion were studied at both macroscopic and microscopic levels, when used to impregnate Norway spruce wood with the Linotech process. The effects of raw material properties, and treatments prior to impregnation, on retention of oil were also quantified. Furthermore, resulting crack development, modulus of elasticity and dimensional stability after impregnation was analysed. Finally, the possible use of Near-Infrared Spectroscopy measurements to estimate global oil uptake in impregnated wood was evaluated as well. There were significant differences in uptake between different wood tissues. Water-filled porosity (water volume divided by porosity volume) and basic density had significant effects on oil retention levels within tissue types. In addition, treatments prior to impregnation affected the oil retention levels. Furthermore, there were relatively good fits of the derived linear regressions predicting the retention of oil within all tissue types (0.85, 0.79, 0.66 and 0.69 in r2 for mature sapwood, juvenile sapwood, mature heartwood and juvenile heartwood, respectively). Heartwood/mature wood and heartwood/juvenile wood showed 10-20 % weight increases due to linseed oil uptake, compared to 30-50 % in sapwood/mature wood in one experiment. One overall regression equation predicting oil uptake, based on Near Infrared Spectroscopy measurements, showed an r2 as high as 0.89. No surface cracks due to impregnation were found in sapwood samples and only occasional cracks in heartwood samples. Internal cracks with a radial orientation occurred more frequently in heartwood samples than in sapwood samples. There was a clear negative correlation between the initial water-filled porosity and the abundance of cracks that developed. The flexural modulus was largely unaffected by impregnation; however, the variation seems to become lower for impregnated sapwood specimens than for control specimens. The effects of the impregnation on dimensional stability, tested in a water soaking experiment, were strongest in dried mature sap and heartwood tissue specimens (Anti-swelling efficiency 29.2-22 % and < 20 %, respectively). However, it also had positive effects on specimens representing other tissue and pre-impregnation treatment combinations. The treatments eliminated much of the variation in swelling and shrinking coefficients observed between untreated tissues. The results of the presented studies imply that it is possible to fully impregnate Norway spruce wood with a hydrophobic oil in a commercial process and to produce durable wood-based materials with homogenous properties. Furthermore, it seems possible to develop evaluation methods that allow adequate setting of process parameters and rapid and accurate measurements of oil uptake during the impregnation process. Thus, wood-based materials could be created according to set specifications.

Authors/Creators:Ulvcrona, Thomas
Title:Impregnation of Norway spruce (Picea abies L. Karst.) wood with hydrophobic oil
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :September 2006
Number of Pages:31
ALLI. Ulvcrona, T., Lindberg, H. & Bergsten, U. 2006. Impregnation of Norway spruce (Picea abies L. Karst.) wood by hydrophobic oil and dispersion patterns in different tissues. Forestry 79(1), 123-134. II. Ulvcrona, T. & Bergsten, U. 2006. Possibilities for compositional tailoring of Norway spruce (Picea abies L. Karst.) wood using a hydrophobic oil impregnation process. Holz als Roh- und Werkstoff URL: http://DOI 10.1007/s00107-006-0137-5. III. Ulvcrona, T., Lindberg, H. & Bergsten, U. Effects of initial water-filled porosity on macroscopic cracks and mechanical properties of Norway spruce (Picea abies L. Karst.) wood tissues after impregnation with a hydrophobic oil. Proceedings Fifth IUFRO Workshop: Connections between Forest Resources and Wood Quality: Modelling Approaches and Simulation Software. Waiheke Island Resort, Auckland, New Zealand November 20-27, 2005. (In Press). IV. Ulvcrona, T. Determination of shrinkage/swelling coefficients of various types of Norway spruce (Picea abies L. Karst.) tissues after impregnation with a hydrophobic oil. (Manuscript). V. Lindeberg, J. & Ulvcrona, T. Potential use of Near-Infrared Spectroscopy to evaluate hydrophobic oil uptake in wood. (Manuscript).
Place of Publication:Umeå
ISBN for printed version:91-576-7137-0
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:picea abies, improved wood, wood preservation, linseed oil, shrinkage, swelling, infrared spectrophotometry
Keywords:Oil uptake, cracks development, mechanical properties, dimensional stability, Near Infrared Spectroscopy, new products development, material properties, supply chain.
Permanent URL:
ID Code:1214
Department:(S) > Institutionen för skogsskötsel
Deposited By: Thomas Ulvcrona
Deposited On:26 Sep 2006 00:00
Metadata Last Modified:02 Dec 2014 10:10

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