Thiol-X reactions exhibit many desirable properties and are considered click reactions. They have the advantages of being resistant to oxygen inhibition, polymerize rapidly under mild conditions, and exhibit delayed gelation due to their step-growth mechanism. [1] Available multifunctional thiols are often derived from esterification reactions involving mercaptopropionic or mercaptoacetic acid. The thiol-X networks formed from these available substrates suffer from degradation due to ester hydrolysis. This behavior limits their implementation in several potential applications. In this study a multifunctional thiol tetra(2-mercaptoethylene)-silane (SiTSH) with no degradable moieties is synthesized and used in stoichiometric reactions with 1,3,5-triallyl-1,3,5-triazyne-2,4,6-trion (TTT) , divinyl sulfone (DVS) and 2,2 - Bis(acryloxy)methyl]butyl acrylate (TMPTA). The same vinyls are reacted with ester-containing pentaerythritol tetra(3-mercapropionate) (PETMP) for comparison (Table 1). Depending on the reaction type they were initiated either by light using 1 wt% bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide-BPO or thermally at 80 oC using 1wt% 2,2,6,6-tetramethyl-1-piperidynyl-N-oxy (TEMPO). From the tabulated results the following conclusion can be drawn; the novel thiol-X materials with no hydrolitically degradable esters combine all benefits of step-growth reactions such as high conversion and uniform network structure and at the same time eliminate many existing drawbacks including increased Tg and significantly improved solvent resistance and stability. [1] Charles E. Hoyle, Andrew B. Lowe, and Christopher N. Bowman. Chem. Soc. Rev. 39, 1355-1387; (2010)

Ester-free thiol-X resin: A new material with enhanced mechanical properties

249th National Meeting (2015)

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