Silicon‐based mercaptans: High‐performance monomers for thiol‐ene photopolymerization

• Published in: Journal of polymer science. Part A, Polymer chemistry Vol. 54; no. 3; pp. 418 - 424
• Main Authors: Roth, Meinhart, Oesterreicher, Andreas, Mostegel, Florian H, Moser, Andreas, Pinter, Gerald, Edler, Matthias, Piock, Richard, Griesser, Thomas
• Format: Journal Article
• Language: English
• Published: Wiley 01.02.2016
• Subjects: glass transition; polymerization; polymers; resins; storage quality; temperature; thiols
• ISSN: 0887-624X; 1099-0518
• DOI: 10.1002/pola.27792

Ester‐free silane and siloxane‐based thiol monomers were successfully synthesized and evaluated for application in thiol‐ene resins. Polymerization reaction rates, conversion, network properties as well as degradation experiments of those thiol monomers in combination with triallyl‐1,3,5‐triazine‐2,4,6(1H,3H,5H)‐trione (TATT) as ene component were performed and compared with formulations containing the commercially available mercaptopropionic ester‐based thiol pentaerythritol tetra‐3‐mercaptopropionate. Kinetic analysis revealed appropriate reaction rates and conversions reaching 90% and higher. Importantly, storage stability tests of those formulations clearly indicate the superiority of the synthesized mercaptans compared with pentaerythritol tetra‐3‐mercaptopropionate/TATT resins. Moreover, photocured samples containing silane‐based mercaptans provide higher glass transition temperatures and withstand water storage without a significant loss in their network properties. This behavior together with the observed excellent degradation resistance of photocured silane‐based thiol/TATT formulations make these multifunctional mercaptans interesting candidates for high‐performance applications, such as dental restoratives and automotive resins. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 418–424