Abstract: Hyperbranched polyurethanes (HBPU) from the third generation to the sixth generation were synthesized from 2,4-diisocyanatotoluene（TDI）and trimethylolpropane. The products were characterized using Fourier transform infrared spectroscopy（FTIR）, XRD, and differential scanning calorimetry（DSC）. It was found that the -NCO of TDI was reacted completely. The d-spacing from the third generation to the sixth generation were 0.41，0.46，0.475，0.414 nm, respectively. With the increasing generation, the glass transition temperature (Tg) decreased from 117.29 ℃ of the third generation to 69.14 ℃ of the sixth generation regularly. Blending 15 wt % of stearic acid modified HBPU(HUPU-SA) with liner PU, the tensile strength and enlongation at break of increased 4.1 and 4.2 times, respectively.

Key words: hyperbranched polyurethane, 2, 4-diisocyanatotoluene, trimethylolpropane, synthesis, characterization