Oxidized lignosulfonate (LS-OB) displays a high crosslinking during th
ermal condensation. When LS-OB was used as a partial substitute of ure
a-formaldehyde (UF) in wood adhesive, a positive effect on the curing
of resin could be observed. With 30-40% substitution, no detriment in
strength properties of particleboard was observed. Polycondensation of
lignin and UF could occur between methylol groups in UF resin and hyd
roxyl and carbonyl groups in lignin, through ether bonds and methylene
bridges. A high surface activity of LS-OB would reduce the surface te
nsion of binder solution and facilitate its distribution on wood parti
cles, improving consequently the strength properties of particleboard.
(C) 1994 John Wiley & Sons, Inc.