Investigation of the Reactivity of Epoxide Monomers in Photoinitiated Cationic Polymerization

Abstract

An investigation of the photoinitiated cationic ring-opening polymerizations of various epoxy monomers was conducted using real-time infrared spectroscopy and optical pyrometry. Several types of behavior were observed and interpreted on the basis of the relative stabilities of the secondary and tertiary oxonium ion intermediates that are generated during the ring-opening polymerization of these monomers. Based on the mechanistic interpretations proposed, attempts were made to accelerate the photopolymerizations of epoxy monomers that undergo overall slow reaction as a result of the presence of an induction period. Three general methods were effective for the acceleration of the photopolymerizations of these and other epoxy monomers: (1) carrying out the photopolymerizations at higher temperatures, (2) copolymerization with more reactive monomers, and (3) the use of free radical photoinitiators.

Synthesis of Organosilica Films Through Consecutive Sol/Gel Process and Cationic Photopolymerization

“…It was thus postulated that hydrolysis and condensation of GPTMS might be affected by another phenomenon. As reported in several studies involving glycidyl ether monomers, [36][37][38] the conjunction of an epoxy-ring and an ether group in the same molecule is known to increase hydrogen bondings and favor the formation of stable multiply hydrogen bonded structures in the presence of water. Jelinski et al [39] described notably the nature of the water-epoxy interactions, providing evidence that water molecules in the presence of epoxy resins could be trapped in such structures, thereby limiting their motion and availability for hydrolysis.…”

Control of reactions and network structures of epoxy thermosets

“…In their simplest form, they initiate polymerization under quite energetic UV radiation (220-300 nm). Their remarkable initiation efficiency and photosensitivity has contributed to their successful use in the polymerization of a large variety of epoxy monomers [218,219,278,[280][281][282][283][284][285]. Their initiation mechanism is representative of the general route to produce cationic species from onium salts and is described in Fig.…”

Fracture toughness of difunctional epoxy resin/thermally latent initiator system modified with polyesters

“…Recently, cationic polymerization of epoxy resins has been studied intensively [10,11]. The latent initiator exhibits the activity at certain external stimulation, such as heating or photoirradiation [12].…”