Mechanical and Thermal Properties of Polyurethane Elastomers Synthesized with Toluene Diisocyanate Trimer

A series of polyurethane elastomers (PUE) incorporating TDI (toluene diisocyanate) trimer were synthesized via an in-situ polymerization and prepolymer process. It was found that for the sample with 10 wt% or less TDI trimer, the stress–strain curves of PUE exhibited the characteristics of a ductile failure with relatively high tensile strength and elongation at break. However, with incorporation 20～30 wt% of TDI trimer, the samples changed to brittle fracture. All PUE samples exhibited a loss peak corresponding to the glass transition temperature (T_g ) of the soft-segments, which shifted to higher temperature and decreased in peak height by incorporation of the three-functional isocyanurate rings. Although the TDI trimer modified PUE showed only slightly higher onset and peak degradation values than that of PUE in the absence of TDI trimer, there were still big differences in the end temperatures of the second stage. The value of activation energy and frequency factor fluctuated for varying samples, indicating that the thermal stability of PUE can be improved to a certain degree by incorporation of TDI trimer, but not so remarkably.