Synthesis and properties of trifluoromethyl organosilicon cycloaliphatic epoxy monomers for cationic photopolymerization

The cycloaliphatic epoxy compounds have been widely used as the monomers in cationic photopolymerization and the fluorine-modified organosilicon materials combine the merits of both organosilicon and organofluorine. In this work, three trifluoromethyl organosilicon cycloaliphatic epoxy monomers with different chain length (CE-FSin, n = 3, 6, 9) were designed and prepared by using a facile two-step synthesis and very competitive raw materials. CE-FSin showed good ability to cationically photopolymerize. The final conversion of the alicyclic epoxy group of CE-FSin systems reached up to 84.0% under the irradiation for 900 s. The addition of CE-FSin enhanced the surface water repellency, heat resistance, elongation at break and glass transition temperature (Tg) of the cured film because of the presence of organosilicon chain and trifluoromethyl group of CE-FSin. The cured film of CE-FSi3-0.5% had the largest water contact angle (105.0(circle)), while the cured film of CE-FSi9-0.5% had tensile strength of 0.49 MPa and elongation at break of 68.51% that was three folds as that of the blank control. The addition of CE-FSin had no obvious influences on the adhesion forces of the cured films, but decreased the pencil hardness.

Automated summary

In this study, three trifluoromethyl organosilicon cycloaliphatic epoxy monomers with different chain length were designed and prepared. CE-FSin showed good ability to cationically photopolymerize. The addition of CE-FSin enhanced the surface water repellency, heat resistance, elongation at break, and glass transition temperature (Tg) of the cured film.