A Visible-Light Curing system of Diphenyliodonium Salt/BODIPY dyes/Bisphenol-A Epoxy Resin Under Halogen Lamp

Abstract

Bisphenol-A epoxy resin have attracted much attention due to its good mechanical properties after curing. In this paper, a visible light curing system of bisphenol-A epoxy resin (E51) initiated by diphenyliodonium hexafluorophosphate (IOPF) and boron dipyrromethene-based (BODIPY) photosensitizers (BODIPY-1 and (BODIPY-2) under a halogen lamp (380-580 nm) was investigated. BODIPY dyes are well known long-wavelength photosensitizers, which is good for IOPF to expand absorption to visible light region. BODIPY-1 and BODIPY-2 are intermediates that reported in our previous work. When IOPF/BODIPY-1 is 2wt%/1wt%, E51 achieves epoxy conversion up to 60% in 0.18 mm thick molds. The Illumination of the halogen lamp is as low as 25.0 mW/cm2. Under same condition, the epoxy conversions of IOPF/BODIPY-2/E51 and IOPF/E51 are about 50% and 20%. When filters were used, IOPF/BODIPY/E51 was effectively cured under light irradiation of 460 nm and 540 nm, and only IOPF is not able to initiate E51 at these wavelengths.