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 depen
dence 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 t
he plots of the residuals are more random. The weight intrinsic viscos
ity, [eta(w)], composed of the oligomer component, O-[n]w, and the oli
gomer-solvent interaction component, I-[n]w, was calculated from the i
ntercept of the plot of 1/ln eta(r) vs. 1/w(0). The parameter I-[eta]w
, related to the solvent molar volume and the distance between the oli
gomer and solvent partial cohesion parameter coordinates, indicates th
e degree of interaction between the oligomer and solvent. The partial
cohesion parameters of the oligomers obtained by the group-contributio
n method were used for calculating the interaction component of oligou
rethane diols. (C) 1997 John Wiley & Sons, Inc.