Synthesis of UV-curable hyperbranched polyurethane (meth)acrylate oligomers via thiol-ene “click” chemistry

First, the second-generation hyperbranched poly(amine-ester) (G2-OH) was successfully prepared by thiol-ene “click” chemistry. Subsequently, a series of photosensitive hyperbranched oligomers (G2-ORs) were synthesized by facile modifications of the G2-OH with acryloyl chloride, methacryloyl chloride, IPDI-HEA, and IPDI-HEMA, respectively. The structures of hyperbranched oligomers were characterized by element analysis, FT-IR, 1 H NMR, GPC and viscosity measurement. It was shown that these synthesized oligomers have narrow molecular weight distribution and low intrinsic viscosity at 30°C. UV–vis spectra results showed that the G2-ORs had sharp absorption bands at around 202 nm. The results of photosensitivities measurement indicated that the G2-Macr shows the highest photosensitive than other hyperbranched oligomers in the absence of photoinitiator. In addition, these UV-cured photosensitive G2-ORs had good thermal properties. The solubilities of the synthesized hyperbranched oligomers were also examined. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013