A Physico-chemical Study of Elastomeric Polyurethans

Abstract

Polyurethan prepolymers prepared by the reaction of polypropylene glycol (PPG) with tolylene diisocyanate (TDI) are cross-linked with trimethylol propane (TMP) to afford elastomeric polyurethans. Although the reaction rate of TDI with PPG increases remarkably with TDI/PPG molar ratio (R), the reaction does not follow a simple second-order mechanism. The curing of the prepolymers with TMP is influenced greatly by R, by the time (t) of prepolymer formation, and also by the amount of TMP. On the other hand, the effects of other curing agents, temperature and inorganic fillers upon the curing are examined.