Urethane-forming reaction kinetics of natural oil polyols versus petroleum-based polyether polyol

摘要

Urethane-forming reaction kinetics of isocyanate with natural oil polyols (NOPs) with pendant reactive hydroxyls was compared to that of the petroleum based polyether polyol with terminal hydroxyls. The non-catalyzed urethane forming kinetic study in toluene shows lower activation energy for pendant hydroxyls of the synthetic and naturally occurring NOP compared to terminal hydroxyls of the polyether polyol. At low temperatures in the non-catalyzed reaction in toluene, the NOPs showed higher reactivity with isocyanate, which was correlated with faster gel time in bulk polymerization. However, in toluene, the reactivity of polyether polyol increases at a faster rate with temperature, and in toluene and bulk reactions the polyether polyol shows higher response to dibutyltin dilaurate catalyst. The results indicate that relative reactivities of NOPs compared to polyether polyols are not necessarily lower in urethane forming reactions, and in fact under certain conditions can be higher, which needs to be taken into consideration during the incorporation of NOPs in polyurethanes.