Photocrosslinkable Vinyl Esters with α, β-Unsaturated Ketone Groups in the Backbone

Abstract

Abstract Five vinyl esters with α, β-unsaturated ketone groups in their backbones have been synthesized from the corresponding diepoxides and acrylic acid with benzyltrimethylammonium methoxide as catalyst. the resins have been characterized by UV, IR, and mass spectral analysis, and their photoreactions have been studied under intense UV irradiation. the vinyl esters have been found to crosslink with UV light much faster than the parent diepoxides. on the other hand, a vinyl ester obtained from diglycidyl ether of Bisphenol A (VE) without the α, β-unsaturated ketonic group undergoes very slow photocrosslinking. Interestingly, the vinyl esters also cure chemically with styrene, methyl ethyl ketone (MEK) peroxide, and cobalt naphthenate within 30 min at 98°C, with the exception that VE does not crosslink under similar conditions. This leads to the conclusion that synergy in photo- and chemical curing can be obtained by symmetrically coupling the vinyl end groups of vinyl esters with the α, β- unsaturated k...