A substantively bonded water repellent treatment based on chromium carboxylates
J K Wright, W B Banks, W J Eilbeck
Chromium carboxylates soluble in toluene have been synthesised and applied to Scots pine (Pinus sylvestris) sapwood. Without any further treatment, the compounds may be readily leached from wood surfaces with toluene. After a period of heating however, they become fixed to the cell wall, substantial amounts being resistant to leaching even under reflux conditions for several hours. Treatment of wood polysaccharide and lignin fractions separately, indicates that most of the fixation occurs to lignin, although the polysaccharides may be involved to a lesser extent. Swelling and water sorption tests have been carried out on small cross-sectional wafer specimens treated with the chromium carboxylates. These show that the treatments impart significant levels of water repellency and that the water repellent effect persists much better than with conventional resin/paraffin wax treatments.