[Effect of organic tin on the morphology and mechanical properties during polyurethane-urea curing process]

The mechanical properties and morphology of crosslined PUU in bulk quasi-prepolymer process was studied by in situ FTIR. From the quantitative change of carbonyl FTIR spectra, the development of morphology between noncatalyzed and catalyzed polymerization process was discussed in detail. The effect of organic tin concentration on the mechanical properties was investigated. It showed that urea carbonyl splitted many small weak bands at different sites with increasing of organic tin concentration, and the catalyst played an important role in controlling the morphology and mechanical properties. It also showed that the mechanical properties reached extreme value when the rate constant of -NCO/-OH reaction equate the rate constant of -NCO/-OH reaction.