Synthesis and Cationic Photopolymerization of Novel Monomers Based on Dicyclopentadiene

Abstract

A series of novel epoxide monomers and oligomers based on dicyclopentadiene (DCPD) were prepared using straightforward synthetic methodology. The differentiated reactivity of the two double bonds in DCPD makes it possible to conduct the addition of alcohols and silanes preferentially at the norbornenyl double bond. Epoxidation of these adducts afforded mono- and difunctional monomers bearing epoxycyclopentyl groups. These epoxide monomers display excellent reactivity in the photoinitiated cationic ring-opening polymerizations using diaryliodonium salt and other onium salt photoinitiators. The high reactivity of these novel DCPD monomers can be attributed to the high ring strain present in the epoxycyclopentyl ring system. Also prepared during the course of this work were two inorganic/organic hybrid systems in which epoxy DCPD moieties are placed as pendant groups onto a siloxane backbone. Photopolymerization of these oligomers also takes place very rapidly under UV irradiation conditions to yield glassy resin matrixes with very good thermal oxidative resistance.