title: Ester-free Thiol-X Resins: New Materials with Enhanced Mechanical Behavior and Solvent Resistance.
abstract: A series of thiol-Michael and radical thiol-ene network polymers were successfully prepared from ester-free as well as ester-containing monomer formulations. Polymerization reaction rates, dynamic mechanical analysis, and solvent resistance experiments were performed and compared between compositions with varied ester loading. The incorporation of ester-free alkyl thiol, vinyl sulfone and allylic monomers significantly improved the mechanical properties when compared with commercial, mercaptopropionate-based thiol-ene or thiol-Michael networks. For polymers with no hydrolytically degradable esters, glass transition temperatures (Tg's) as high as 100 °C were achieved. Importantly, solvent resistance tests demonstrated enhanced stability of ester-free formulations over PETMP-based polymers, especially in concentrated basic solutions. Kinetic analysis showed that glassy step-growth polymers are readily formed at ambient conditions with conversions reaching 80% and higher.
authors.affiliation: Department of Chemical and Biological Engineering, University of Colorado, UCB 596, Boulder, Colorado 80309, United States ; Faculty of Chemistry, Department of Polymer Chemistry, Maria Curie-Sklodowska University, pl. Marii Curie-Skłodowskiej 5, 20-031 Lublin, Poland.
authors.forename: Maciej
authors.initials: M
authors.lastname: Podgórski
authors.affiliation: Department of Chemical and Biological Engineering, University of Colorado, UCB 596, Boulder, Colorado 80309, United States.
authors.forename: Eftalda
authors.initials: E
authors.lastname: Becka
authors.affiliation: Department of Chemical and Biological Engineering, University of Colorado, UCB 596, Boulder, Colorado 80309, United States.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Chatani
authors.affiliation: Department of Chemical and Biological Engineering, University of Colorado, UCB 596, Boulder, Colorado 80309, United States.
authors.forename: Mauro
authors.initials: M
authors.lastname: Claudino
authors.affiliation: Department of Chemical and Biological Engineering, University of Colorado, UCB 596, Boulder, Colorado 80309, United States.
authors.forename: Christopher N
authors.initials: CN
authors.lastname: Bowman
keywords: DMA; hydrolytic degradation; thiol-Michael reaction; thiol-ene reaction