A Comparison on Penetration of Silica Sol in Scots pine and Southern pine wood
Mingyang Sun, Jinzhen Cao
Penetration is one of the most important issues to be considered in wood impregnation with various kinds of chemicals in liquid form. Scots pine (Pinus sylvestris) and Southern pine (Pinus spp.) are two frequently used wood species for treatment, such as preservative treatment. With the development of treating systems, some micro- or nano-sized aqueous modifiers are emerging in the market, which puts forward new requirements to understand the penetration as well as the distribution of these non-solubilized particles in wood. In this study, two particle sized silica sols (30 nm, 150nm) were used to treat both Scots pine and Southern pine sapwood at non-pressure and 0.4 mPa pressure conditions. The liquid absorption (LA), the weight percent gain (WPG), and the silicon distribution by both gravimetric method and SEM-EDXA were investigated to compare the influence of particle size and treating pressure on penetration of silica sols in two wood species. The results showed that southern pine has better penetration and more even silica distribution than Scots pine, which is extremely significant when the particle size is comparatively big, such as 150 nm as used in this study. Dispersions with very small particle size, such as 30 nm silica sol, are not difficult to treat for both wood species under certain pressure.