UV-curing of hyperbranched polyurethane acrylate-polyurethane diacrylate/SiO2 dispersion and TGA/FTIR study of cured films

摘要

UV-curable hyperbranched polyurethane acrylate-polyurethane diacrylate/SiO2 dispersion(HBPUA-PUDA/SiO2) was prepared with isophorone diisocyanate(IPDI),hyperbranched polyester Boltorn H20(H20),hydroxy-ethyl acrylate(HEA),polyethyleneglycol(PEG-200) and nano-SiO2.The UV curing kinetics of the films was investigated by FTIR.The results show that the curing speed of the films increases with the adding of nano-SiO2 and decreases with the adding of PUDA due to the slower chain movement.The thermal stability of the HBPUA-PUDA/SiO2 films was studied by using thermogravimetric analysis coupled with Fourier transform infrared spectroscopy(TGA/FTIR).The results show that all films exhibit two degradation stages located at about 320 and 440 °C corresponding to the degradation for hard segments of urethane-acrylate and the degradation for soft segment and polyester core.In addition,the results from the analysis of TGA/FTIR also indicate that the decomposition temperature of HBPUA-PUDA/SiO2 film is 15 °C higher than that obtained for pure polymer.The degradation mechanism was proposed according to TGA/FTIR results.