Group contribution modeling of viscosity during urethane reaction

Based on experimental viscosity data collected from single material and binary system mixtures, a group contribution method was introduced to estimate viscosities of a range of polyol oligomers and urethane polymers at temperatures from 25 to 150 degrees C. Use of mixture rules then extends the estimation method to multi-component reacting systems. Mixture viscosity data were used to determine the Gibbs free energy (G) in the Grundberg-Nissan equation which can be used to estimate mixture viscosities with correction for some non-idealities. The resulting model is able to accurately predict mixture viscosities based on binary interaction. The goal of this work is to estimate the viscosities of urethane-forming reactions; accurate viscosity information is critical as an intermediate step to predict how successful a foam formulation would be and to ultimately estimate the final physical properties of the foam.