| UV-curing technology has been widely employed in industry as a green and environmental friendly route with the advancement of science and technology. The fluorinated polymer has great prospects in functional coatings due to its low surface energy, excellent thermal stability, aging and chemical resistance, etc. Therefore, the combination of UV-curing technology and fluorinated polymer is of great importance.Fluorine-containing acrylate resins are often used as low surface energy coatings. They possess controllable structure, simple preparation and easy usage. In this paper, epoxy functional fluorinated acrylate resins were synthesized via solution polymerization which can be used in UV-cuing system. Low surface free energy films were obtained by thermal curing, cationic UV-curing and free radical-cationic hybrid UV-curing, respectively. UV-curing kinetics was studied as well. Moreover, the GBF resins were characterized by FT-IR, NMR, DSC and TGA. The cured films were studied by SEM-EDS, contact angle. The main works are as follows:(1)In this paper, glycidyl methacrylate(GMA), butyl acrylate(BA) and dodecafluoroheptyl methacrylate(G04) were used as raw materials, and epoxy functional fluorinated acrylate resins(GBF resins) were obtained via solution polymerization. GMA, BA, G04 played different but important roles respectively, where GMA provides UV-curing functionality, BA offers good compatibility and G04 brings low surface free energy. FT-IR, 1H NMR of GBF reins showed that the monomers took part in polymerization and the products were consistent with the desired objectives. The introduction of fluorinated monomer increased Tg and thermal stability of GBF resins. The contact angle and surface free energy results showed that the dosage of fluorinated monomer has a great effect on the contact angle of films. When adding 5wt%of G04, the water and oil contact angle increased about 20°. When the content of G04 was reached 20wt%, the water and oil contact angle were reached 110° and 53° respectively, the surface free energy of the film achieved 18.07dyn/cm.(2)The cationic UV-curing coatings were obtained by mixing GBF resin with cationic photoinitiator PI 820. The curing kinetics and properties of cured films were studied. RT-IR results showed that UV light intensity, the content of PI 820 and G04 had a great influence on the kinetics of UV-cured coatings. Strong UV light intensity and higher dosage of PI 820 led to higher conversion of epoxy group. The fluorinated monomers also accelerated the conversion of epoxy group. Additionally, we found that the content of cured films increased with time which confirming the "post curing" effect. According to SEM images, apparent phase separation can be observed which resulted from the solubility of GBF resins. EDS results showed that the fluorinated segments were not completely migrated to the surface of cured films. The contact angle indicated the dosage of PI820 affected the contact angle which was consistent with the RT-IR analysis. Similar to chapter 2, the fluorinated monomer has improved the hydrophobicity and oleophobicity and decreased the surface free energy of cured films, whereas heat treatment has a positive effect on the hydrophobicity and oleophobicity of cured films.(3)Free radical-cationic hybrid UV-curing coating were prepared via blending GBF resin, epoxy acrylate resin(EA),1,6-hexanediol diacrylate(HDDA), PI 820 with free radical photoinitiator IRGACURE 184. The curing kinetics and surface properties were discussed. RT-IR results showed that the conversion of epoxy group was increased with the increasement of GBF resin, while the conversion of C=C presented an increasement and a decreasement. During the hybrid UV-curing process, the polymerization of C=C was dominant, each of them presented good synergy effect. Gel content result showed that the gel content of hybrid UV-cured films was greater than that of cationic UV-cured films, in addition, hybrid UV-cured films’gel content was decreased with the increasement of GBF resin. Contact angle and surface free energy analysis indicated that a small content of GBF resin could improve the hydrophobicity and oleophobicity of hybrid UV-cured films, which decreased the surface free energy of films. What’s more, heat treatment also enhanced the hydrophobicity and oleophobicity of hybrid UV-cured films which was similar to cationic UV-cured films. It’s found that the hybrid UV-cured films decomposed completely at 450℃ and exhibited excellent thermal stability according to TGA. Furthermore,’as the increasement of GBF resin, thermal stability of hybrid UV-cured films decreased. |
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