High-T sub(g) Thiol-Click Thermoset Networks via the Thiol-Maleimide Michael Addition

• Published in: Macromolecular rapid communications. Vol. 37; no. 13; pp. 1027 - 1032
• Main Authors: Parker, Shelbi, Reit, Radu, Abitz, Haley, Ellson, Gregory, Yang, Kejia, Lund, Benjamin, Voit, Walter E
• Format: Journal Article
• Language: English
• Published: 01.07.2016
• Subjects: Dynamical systems; Dynamics; High temperature; Homogeneity; Mechanical analysis; Networks; Reaction mechanisms; Thermosetting resins
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.201600033

Thiol-click reactions lead to polymeric materials with a wide range of interesting mechanical, electrical, and optical properties. However, this reaction mechanism typically results in bulk materials with a low glass transition temperature (T sub(g)) due to rotational flexibility around the thioether linkages found in networks such as thiol-ene, thiol-epoxy, and thiol-acrylate systems. This report explores the thiol-maleimide reaction utilized for the first time as a solvent-free reaction system to synthesize high-T sub(g) thermosetting networks. Through thermomechanical characterization via dynamic mechanical analysis, the homogeneity and T sub(g)s of thiol-maleimide networks are compared to similarly structured thiol-ene and thiol-epoxy networks. While preliminary data show more heterogeneous networks for thiol-maleimide systems, bulk materials exhibit T sub(g)s 80 degree C higher than other thiol-click systems explored herein. Finally, hollow tubes are synthesized using each thiol-click reaction mechanism and employed in low- and high-temperature environments, demonstrating the ability to withstand a compressive radial 100 N deformation at 100 degree C wherein other thiol-click systems fail mechanically. The thiol-maleimide Michael addition is demonstrated as a reaction mechanism used to synthesize high-T sub(g) thiol-click thermosetting networks that exhibit T sub(g)s 80 degree C higher than similarly structured thiol-click systems. Hollow cylindrical samples of each composition are fabricated and loaded radially, showing the thiol-maleimide thermosets withstanding a 100 N load at elevated temperatures.