Concentration dependence on viscosity of oligourethane diols

To obtain viscosity suitable for application, relatively low molecular weight polymers, i.e., oligomers, are used in the formulation of high solids coatings. To support this requirement, the concentration dependence of the viscosity of synthesized oligourethane diols in different solvents was analyzed using Erickson's models. By regression analysis, it was found that the correlation coefficients are fairly good and the plots of the residuals are more random. The weight intrinsic viscosity, η_o], composed of the oligomer component, O_5η]o, and the oligomer-solvent interaction component, I_η]o, was calculated from the intercept of the plot of 1/ln η_r vs. 1/o₀. The parameter I_η]o, related to the solvent molar volume and the distance between the oligomer and solvent partial cohesion parameter coordinates, indicates the degree of interaction between the oligomer and solvent. The partial cohesion parameters of the oligomers obtained by the group-contribution method were used for calculating the interaction component of oligourethane diols. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1343–1351, 1997