Non-polluting systems based on waterborne polyurethanes were obtained from hydroxy-terminated polybutadiene (HTPB) (`Mn = 3500), poly(propylene glycol) (PPG) (`Mv = 2490), isophorone diisocyanate (IPDI) and dimethylolpropionic acid (DMPA). The aqueous dispersions, with 35 % of solid content, were stable for nearly a month and their apparent viscosity ranged from 30 to 220 cP. An increase in HTPB content in the formulations led to an increase in the average particle size of the dispersions. This increase also promoted an improvement in the mechanical resistance of cast films from the aqueous dispersions. The adhesive properties of dispersions as wood coatings were determined and it was observed that the presence of HTPB improved the adhesion between coating and substrate.
HTPB; PPG; IPDI; DMPA; polyurethanes; aqueous dispersions
