Stabilization of Wood-Resin Emulsions by Dissolved Galactoglucomannans and Galactomannans

摘要

Galactoglucomannans (GGM) and galactomannans (GM) as steric stabilizers of colloidal wood-resin emulsions were investigated at various CaCl_2 concentrations. Both acetylated GGM and GM were able to stabilize wood-resin droplets. The higher the molar mass of the mannan, the better was its stabilizing effect. The number of galactose side groups was not as decisive. Unmodified GM stabilized wood-resin emulsions at a mannan concentration as low as 5 mg/L (or ～ 0.05 mg_(GM)/mg_(resin)), in the presence of up to 30 mmol/L CaCl_2. Deacetylated GGM were poor wood- resin stabilizers. For comparison, a number of other polymers were also tested. Birch xylan was an excellent stabilizer, even at 5 mg/L, while neutral and cationic starches were not very effective.