| In this paper,three organic additives such as organic ultraviolet absorbers(UV-326), hindered amine light stabilizer(HALS-622) and antioxidants(AO-1010) are added to the alicyclic polyurethane film(isophorone diisocyanate as hard segment, and polytetramethylene glycol as soft segment), respectively. The experiments for the films exposed to UV radiation O3 and UV/O3 atmosphere are performed by using self-developed accelerated aging devices, respectively. The test results of Fourier transform infrared spectroscopy, UV-visible spectroscopy, Thermal gravimetric analysis, the color difference and yellowness index are recorded, which are used to study the weather-resistance properties of the alicyclic polyurethane films and effect of organic additives on weather resistance properties of polyurethane films.The results show that the color difference, yellowness index and –C=O absorbance of UV-vis spectrum of various PU films were gradually increased with aging time during exposed to UV radiation O3 and UV/O3 atmosphere. –NH and –C=O absorption peaks gradually are increased and broaden with the exposure time. While, α/β-CH2 absorption peaks,-C-O-C absorption peaks and –C-NH Coupled vibration peaks are decreased with the exposure time.The results show that UV-326 has a significant effect on improving weather resistance properties of polyurethane films during exposure to UV environment, and AO-1010 has a significant effect on improving weather resistance properties of polyurethane films during exposure to O3 environment. However, either a signal additive has little effect on improving aging resistance properties of polyurethane films during exposure to constant UV radiation with O3 atmosphere.We have studied the photo-oxidative degradation behavior of alicyclic poly(ether-urethane)s film by Fourier transform infrared spectroscopy, and discussed the photo-oxidative degradation mechanism in this article. Further, the way of degradation and degradation products of polyether polyurethane structure are analyzed. it is confirmed that the oxidation of this type of polyurethane results from the important sensitivity of polyether soft to oxidative degradation. Oxidation of the ether groups produced format, which further decomposed to give ethylene and methyl format, and regenerated the formats, until the total disappearance of the ether groups, simultaneously. The decomposition of the urethane functions is mainly due to the cleavage of –C-N bond and –C-O bond, as well as the oxidation of the α methylene groups to the –NH. |
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