The effect of an ionic liquid of imidazolium tetrafluoroborates series on Scots pine wood properties

IRG/WP 07-40357

A Fojutowski, R Szukala, J Pernak

Ionic liquids (ILs) of imidazolium tetrafluoroborates series penetrate Scots pine wood very well and are active against wood destroying fungi. The requirement to use ILs as wood preservatives is determined by the liquid influence on the functional properties of wood. Investigations were undertaken to clarify the influence of an ionic liquid, 3-heptyloxymethyl-1-methylimidazolium tetrafluoroborate = [(C7Om)mim][BF4], on selected physical and mechanical properties of Scots pine (Pinus sylvestris L.) wood. The miniature sapwood samples were subjected to sorption and brushing with [(C7Om)mim][BF4]. The properties of the treated wood were compared with those of control wood, i.e. untreated wood. [(C7Om)mim][BF4] exerted only a very small influence on wood color – the total color change, ?E, amounted to about 5, which facilitated visual distinction of the wood texture, however, the color change of the treated wood was lower when irradiated with a xenon lamp. This demonstrated the resistance of IL-treated wood against color change at exposure to light. In comparison with control wood samples the IL-treated wood samples manifested also lower hygroscopic and absorptive potential. In addition, the relative differences in tensile strength, bending strength and modulus of elasticity between the treated and control samples were statistically insignificant. Compression strength along the grain of treated wood was greater by 1.6% than that of control wood, while the impact strength of treated wood was lower by 7.8% in comparison with control samples. The influence of [(C7Om)mim][BF4] treatment on physical and mechanical properties of wood, although insignificant, was generally positive if the IL is intended for biocidal protection.


Keywords: Ionic liquid, strength, wood properties, wood treatment

Conference: 07-05-20/24 Jackson, USA


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