Photopolymerization of ternary thiol–ene/acrylate systems: Film and network properties

Abstract

Photocurable, ternary‐component mixtures of a 1:1 molar multifunctional thiol–ene (trithiol and triallyl ether) blend and a 16‐functional acrylate based monomer have been photopolymerized, and the final film properties of the ternary crosslinked networks have been measured. The photopolymerization kinetics, morphology, and mechanical and physical properties of the films have been investigated with real‐time infrared, atomic force microscopy, and dynamic mechanical analysis. The photopolymerization process is a combination of acrylate homopolymerization and copolymerizations of thiol with allyl ether and acrylate functionalities. The tan δ peaks of the photopolymerized ternary systems are relatively narrow and tunable over a large temperature range. The morphology is characterized by a distinct phase‐separated nanostructure. The photocured thiol–ene/acrylate ternary systems can be made to exhibit good mechanical properties with enhanced energy absorption at room temperature by the appropriate selection of each component concentration. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 822–829, 2007.

Soy-based UV-curable thiol–ene coatings

“…Further, such homopolymerization was accelerated due to the elimination of oxygen inhibition because of the chain transfer mechanism that was induced by the thiol. 27 This is evidenced by the lack of an induction period for the acrylate conversion as indicated in the RTIR conversion curve, shown in Fig. 8.…”

End Group Reactions of RAFT-Prepared (Co)Polymers

“…The reaction under base or nucleophilic catalysis is also accurately termed a conjugate addition or thiol-Michael reaction and is limited to activated substrates. [132] Of these general reactions, the radical thiol-ene process has been the most extensively used in the polymer and materials fields and most notably as a highly efficient method for preparing near-perfect networks and films, as exemplified by the work of Hoyle and coworkers [133][134][135][136][137][138][139][140][141] and Bowman et al [142][143][144][145][146][147][148] Recently, the thiol-ene reaction has attracted researchers in other areas of synthesis owing, in part, to the recognition of its click [149,150] characteristics. Desirable features associated with the thiol-ene reaction include: (1) hydrothiolation can proceed under a variety of conditions, including via a radical pathway and via catalytic pathways mediated by nucleophiles, bases and acids; (2) a wide range of enes serve as compatible substrates; (3) virtually any thiol can be employed, including highly functional species; (4) these reactions can be extremely rapid and are generally tolerant of the presence of oxygen and moisture.…”

Three‐Dimensional Flexible Electronics Enabled by Shape Memory Polymer Substrates for Responsive Neural Interfaces

“…[32] A slightly modified version of the thiol–ene reaction is the ternary thiol–ene/acrylate reaction where both acrylate homopolymerization and thiol–ene reactions proceed simultaneously. [33,34] This has been shown to be a useful manner of increasing crosslink density and subsequently T g .…”