Effects of fluorine and silicon components on the hydrophobicity failure behavior of acrylic polyurethane coatings

Hydrocarbon acrylic copolymer was synthesized by a radical polymerization route. Fluorine-containing copolymer was prepared via a post-fluorine modification method. Hydrocarbon, fluorine-containing, silicon-containing, and fluorosilicone acrylic polyurethane coatings were prepared by curing reaction of the curing agents and mixtures of the synthesized copolymers and amino silicone, respectively. Indoor atmospheric environment, hygrothermal environment, different temperature environment, as well as xenon arc aging environment were employed to investigate the hydrophobicity failure behavior of the coatings. Chemical structure of the coatings was characterized by attenuated total reflectance Fourier transform infrared spectrum. Water contact angles of the coatings were monitored during the failure process. Thermostability of the coatings was explored by thermo gravimetric analysis. Surface morphology of the coatings was investigated by scanning electron microscopy. Elemental composition of the coating surface was analyzed by a X-ray photoelectron spectrometer. The results showed that the acrylic polyurethane coatings were prepared as expected. In addition, the modification mechanism determined the performance of the coatings in different environments. The fluorine-containing coating performed with better hydrophobicity in the indoor atmospheric environment, hygrothermal environment and low-temperature environment, but failed faster in the high temperature and xenon arc aging environments. The silicon-containing coating exhibited relatively stable hydrophobicity in the high temperature and the xenon arc aging environments. The hydrophobicity of the fluorosilicone coating fell in between that of the fluorine- and silicon-containing coatings under all of the experimental conditions. The fluorine-containing components improved the hydrophobicity of the coatings more effectively, while the silicon-containing components contributed more to the thermo and weather resistance property of the coatings.