Masamitsu Nakabayashi

End-group Analysis of Some Polyether Polyols and Polyester Polyols by Nuclear Magnetic Resonance Spectroscopy

Ring-opening polymerization of monosubstituted ethylene oxides Cl J results in formation of polyether polyols with either primary C 2or secondary terminal hydroxyl group C3D, depen- ding on the mode of C-O-C bond cleavage.This end-group structure is significant, since it is closely related to the reactivity of polyols and affects the properties of polyurethane resin prepared from those polyols and diisocyanates. The application of NMR technique to the analysis of primary hydroxyl groups in polyol are studied in this paper when the hydroxyl is converted into urethane, and it proves to be a simple and convenient method. We also employed the time-average technique of NMR with a Mnemotron Computer of Average Transient to analysis of terminal unsaturation in polyols. It was revealed that poly (oxypropylene)glycol prepared by KOH catalyst contains substan- tially on or a small amount of primary hydroxyl, but more than 40% primary hydroxyl is found in polyether which was prepared by BF, --catalyzed, polymerization, and no matter what the polymerization catalyst is the amount of terminal unsaturation in the resultant polyethers increases by the molecular weight increase of polyether.