Improvement of Method for Determination of Isocyanate Group Content in Polyurethane Prepolymer

This paper represents the improvement of method for determination of isocyanate group content in polyurethane prepolymer. Acetone-dibutylamine method and toluene-dibutylamine method were used separately to determine the isocyanate group content in polyurethane prepolymer. The –NCO content tested by the two methods were close. In the former method, 15-20 mL acetone was used as solvent and the titration end point was easy to confirm. While in the latter method, additional solvent (isopropanol) was used which causes environmental contamination.