氟改性丙烯酸酯共聚物的制备及其涂层表面疏水性能

Preparation of Fluoro-modified Acrylate Copolymer and Hydrophobicity of Coatings Therefrom

使用含有不同长度全氟碳链的全氟烷基乙基醇分别与甲基丙烯酸氯和甲苯二异氰酸酯反应,制备了两种不同的含氟单体TEMAc-n和Fn TDI,然后分别通过自由基共聚合反应和对合成好的常规含羟基丙烯酸酯共聚物进行后改性两种路线,制备了两类含有相同全氟碳链结构的氟改性丙烯酸酯共聚物x TEMAc-n和x Fn TDI及其涂层。利用傅里叶变换红外光谱(FT-IR)和核磁共振(19F NMR)技术对单体和相应共聚物的化学结构进行了表征,用示差扫描量热法(DSC)测试了共聚物的玻璃化转变温度,通过静态水接触角、X射线光电子能谱(XPS)和原子力显微镜(AFM)对共聚物膜层的表面性能进行了表征。结果表明,制备合成了预期的含氟单体和含氟共聚物。随着含氟单体的引入,共聚物的玻璃化转变温度升高,涂层的疏水性能提高。含氟链段的长度对涂层疏水性的贡献大于氟含量的影响,与自由基共聚合方法制备氟改性共聚物x TEMAc-n相比,使用异氰酸酯基含氟单体对常规含羟基丙烯酸酯共聚物进行后改性制备的氟改性共聚物x Fn TDI,成膜时含氟链段更容易向涂层表面迁移,引入较少的含氟单体就可以获得优异的疏水性能。

Perfluoroalkyl ethyl alcohol containing different length of perfluoroalkyl chains were employed to prepared two series of flourine-containing monomers TEMAc-n and Fn TDI by reaciton with chlorine methacrylate and toluene diisocyanate.Two series of fluoro-modified acrylate copolymers x TEMAc-n and x Fn TDI,and coatings therefrom were prepared with the TEMAc-n monomers through free radical polymerization with vinyl monomers and Fn TDI via reaction of the isocyanate groups in their own molecules with the hydroxyl groups in the side chains of the acrylic copolymers,respectively.The chemical structure of the monomers and the corresponding copolymers were investigated by Fourier transform infrared spectroscopy(FT-IR)and nuclear magnetic resonance(19 F NMR).Glass-transition temperature(Tg)of the copolymers were confirmed with differential scanning calorimetry(DSC).Surface properties of the copolymer coatings were characterized by static water contact angle,X-ray photoelectron spectrometer(XPS)and atomic force microscope(AFM),respectively.Results showed that the fluorine-containing monomers and the fluoro-modified copolymers were prepared as expected.Both Tgof the copolymers and hydrophobicity of the corresponding coatings increased as the fluorine-containing monomers were copolymerized.The length of the perfluoroalkyl chains played a more important role in improvement of the copolymer coatings hydrophobicity than fluorine content.More fluorine-containing segments migrated to the coatings surface during the film formation of the copolymers x Fn TDI,resulting in more excellent hydrophobicity of the coatings,compared with the copolymers x TEMAc-n.