Polyurethane Synthesis Under Dilute Conditions: Characterization of the Precursors and Measurement of Intermolecular Bonds

The exact functionalities of various polyoxypropylene triols have been investigated carefully to allow precise determination of intramolecular bonds in polyurethanes synthesized in dilute conditions. Discrepancy between experimental results and classical theories seems to indicate that the capture radius between active sites is far from zero. It appears that there is a linear dependence between cyclization extent and the volume fraction of the diluent, independent of the prepolymer molecular weight. 10 ref.--AA