Preparation and properties of a fluorinated epoxy resin with low dielectric constant

Demand for electronic materials with improved dielectric properties are increasing. One of the ways to reduce the dielectric constant is to incorporate fluorine atoms. In this article, a novel fluorinated epoxy resin (diglycidol ether of 2,4-bis (1,1,1,3,3,3-hexafluoroisopropyl) fluorobenzene (FB-EP)) with 45.7 wt% fluorine content was synthesized from fluorobenzene, epichlorohydrin and hexafluoroacetone. The structures of desired monomers were characterized by NMR and FTIR. The epoxy resin FB-EP was cured by copolymerization with hexahydrophthalic anhydride (HHPA) and by homopolymerization catalyzed with boron trifluoride ethylamine (BF3MEA), respectively. The curing reaction kinetics of the fluorinated epoxy and the properties of the cured materials were studied in comparison with those of common diglycidol ether epoxy resin (BADGE). The results of curing activation energy indicate that FB-EP is reactive as the BADGE, and the four-trifluoromethyl groups on FB-EP do not negatively affect the cationic polymerization reactivity of the epoxy groups. The cured FB-EP materials had lower moisture absorption, and especially lower dielectric constant (Dk, 2.23) and lower dielectric loss (Df, 0.011) in the frequency range of 8.2–12.4 GHz. This article provides a base for further study of fluorinated epoxy resin as advanced electronic materials.