Diels-Alder Trapping of Photochemically Generated o-Quinodimethane Intermediates:An Alternative Route to Photocured Polymer Film Development

摘要

Photolysis of o-methylphenyl ketones generates o-quinodimethane intermediates that can be trapped in situ by dienophiles through Diels-Alder cycloadditions.This well-known photochemical process is applied to a series of six new photoreactive monomers containing bis(o-methylphenyl ketone) functionalities combined with diacrylate and triacrylate esters for the development of acrylic ester copolymer blends.Irradiation of cyclohexanone solutions of the bis(o-methylphenyl ketone)s and acrylate esters produce thin polymer films.Solid state ~(13)C NMR data indicated 47-100% reaction of the bis(o-methylphenyl ketone)s,depending on experimental conditions,to yield the desired products.DSC and TGA analyses were performed to determine the glass transition temperature,T_g,and onset of decomposition,T_d,of the resulting polymer films.A statistical "design of experiments" approach was used to obtain a systematic understanding of the effects of experimental variables on the extent of polymerization and the final polymer properties.