含氟丙烯酸聚氨酯涂层的环境失效行为研究

目的研究含氟丙烯酸聚氨酯涂层作为船壳清漆,在光老化过程中疏水性能和防护性能的失效行为。方法通过接触角、傅里叶变换衰减全反射红外光谱(ATR-FTIR)、原子力显微镜(AFM)形貌,结合交流阻抗(EIS),研究涂层在室内外大气暴露环境、氙灯加速老化试验环境中的老化过程。结果光老化可以使涂层接触角显著降低,疏水性能下降。ATR-FTIR和AFM分析表明,光老化使涂层表面氟含量显著降低,氧含量升高,表面粗糙度增大。与中性盐雾试验相比,氙灯加速老化试验中涂层电阻衰减速度更快。结论光老化过程中,涂层表面分子链断裂使涂层表面氟含量降低,疏水性下降,同时涂层电阻随老化时间延长而降低。

Study on Failure Behavior of Fluorinated Polyurethane-acrylic Coatings

Objective To investigate failure behaviors of fluorinated acrylic polyurethane coating in air environment and xenon accelerated aging test environment. Methods Water contact angle,attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR),atomic force microscope(AFM) and Electrochemical Impedance Spectroscopy(EIS) were conducted to monitor the property variation of the coating. Results The results showed that coating contact angle decreased definitely in xenon accelerated aging test. ATR-FTIR spectra and AFM analysis indicated that the fluorine content decreased, while the oxygen content increased, and the coating surface roughness increased during the xenon lamp accelerated aging process. Coating resistance attenuated faster in xenon lamp accelerated aging test than in neutral salt spray test. Conclusion Photoaging began with a rupture of molecular chain, which led to a decrease of fluorine content, while coating resistance diminished along with time of aging.