Abstract:

Perfluoroalkyoxy-substituted cyclohexene oxides(EFPO1 and EFPO2) were obtained by two-step reactions using the dimer and trimer of hexafluoropropylene oxide and 4-cyclohexene-1,2-dimethanol as main raw materials. The structures of assynthesized products were confirmed by spectroscopy analyses including FT-IR and 1H NMR. These fluoro-epoxides are compatible with the prepolymers such as bisphenol-A diglycidyl ether and ethylene glycol diglycidyl ether, thereby endowing the coatings composed of them with improved hydrophobicity as evidenced by the photoinitiated curing experiments. The preliminary investigation of their UV-curing performance shows that the hydrophobicity increases linearly with increasing fluoro-epoxide content in the composition. As expected, the hydrophobic effect is more pronounced for EFPO2 than EFPO1 at the same conditions, because the former has a longer ferfluoroalkyoxy group. For example, upon addiing 1% mass fraction of EFPO2, the water contact angle of the UVcured films was 99° and was higher 14° than that found for the films without the fluoro-component, whereas the value for EFPO1modified films was 87°. When containing 5% EFPO2, high hydrophobic surface was achieved with a water contact angle of 113 for the UV-cured films. In addition, it should be pointed out that the hydrophobic surface can be further improved by heating the UVcured films at 110 ℃ for 6 h. For the coatings containing 1%~5% EFPO2, the post-heating treatment resulted in a change of the water contact angles from the range 99°~113° to 113°~118°, while the changes were from 87°~100° to 99°~110° for EFPO1 analogs. The thermal migration of fluorochains and aggregation on the film surface seems to be responsible for the enhancement in hydrophobicity. Consequently, this new type of fluorinecontaining epoxy monomers is expected as the surface modifier used in coatings, inks and release materials.

Key words: fluorinated epoxides, UV-curing, hydrophobicity