【摘要】 采用荧光紫外辐照UVB+冷凝的人工加速试验对丙烯酸聚氨酯清漆进行老化试验,用电化学阻抗谱(EIS)评价不同暴露时间涂层的屏障性。结果表明:随着暴露时间增加,一定频率下的低频阻抗模值|Z|下降,表现为时间的变化函数;傅立叶变换红外光谱(FTIR)分析表明,紫外暴露下发生高分子断链涂层降解,而在老化12天后|Z|值的升高可能与分子的重构变化有关;因而,EIS谱的|Z|值可作为一种较为有效的表征参数来反映UV老化后有机涂层的防护性能。更多还原

【Abstract】 An artificial weathering test(UVB radiation/condensation) was used for aging testing of acrylic polyurethane varnish coatings.The barrier protection properties of coatings with different exposure times were evaluated using electrochemical impedance spectroscopy(EIS).The results showed that low frequency impedance|Z|at a fixed frequency decreased with the increase of exposure time which and yielded time series function.Fourier transform infrared spectroscopy(FTIR) indicated that degradation had taken place upon exposure to artificial weathering test,and also appearsed to undergo some molecular segments re-association after 12 days exposure which led to the increase of low frequency impedance.Therefore,low frequency impedance could be used as an appropriate parameter to characterize the protective properties of intact organic coatings.更多还原