STABILITY AND DEPOSITION TENDENCY OF COLLOIDAL WOOD RESIN

The influence of the chemical composition of dispersed wood resin obta ined from Norway spruce and Scots pine on its colloidal stability and deposition tendency was studied. The ability of dissolved glucomannans to stabilise colloidal resin against aggregation with simple electrol ytes was also examined. Free fatty acids increased the stability of wo od resin against aggregation at pH 5. At pH 8 no significant differenc es in the stability between different compositions were found, except for the dispersion of resin from pine heartwood, which was considerabl y more stable against NaCl additions than other dispersions. Different preparations of glucomannans were shown to be effective stabilisers o f colloidal wood resin against aggregation as well as deposition (at p H 5). Additions of free fatty acids increased the deposition tendency at pH 5, but decreased the deposition tendency at pH 8, when CaCl2 was not present in the dispersions. The addition of CaCl2 increased the a mount of deposit both at pH 5 and pH 8.