Supercritical impregnation of wood with siloxane

IRG/WP 12-30595

A Kjellow, F Imsgard, J Fernandes, O Henriksen, E Klaassen, R Wagner, J Delis

This paper describes the effect of supercritical impregnation with siloxane on the water repellency of Scots pine (Pinus sylvestris) sapwood samples. Samples were impregnated with a low amount of siloxane dissolved in supercritical carbon dioxide using isopropanol as a co-solvent. Siloxane retention (i.e. weight percent gain (WPG)) of the treated samples was 1.3 % (w/w) as found by mass balance. The resulting effect on the water repellency of treated samples was examined by submersing small samples (EN 113 size) in water and registering the weight increase over 80 minutes. Average water uptake of treated samples after 80 minutes of submersion was decreased to 39 % of the level of non-treated samples. After 80 minutes of submersion, the treated samples had reached about the same weight gain as the non-treated controls had reached after less than 5 minutes of submersion. The rate of water uptake i.e. weight gain per time unit, was reduced by a factor of more than 40 when treated samples were compared to non-treated samples at the same moisture content.


Keywords: Water repellent, siloxane, supercritical carbon dioxide, impregnation, pine, sapwood

Conference: 12-05-06/10 Kuala Lumpur, Malaysia


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