Highly Tunable Thiol–Ene Networks via Dual Thiol Addition

Abstract

Throughout the past decade, investigations of thick thermoset thiol–ene networks (TENs) have become increasingly prominent in the literature due to facile, quantitative synthesis giving rise to unique network characteristics, specifically high mechanical energy damping. This article reports the synthesis and thermomechanical properties of ternary thiol–thiol–ene systems that exhibit tunable glass transitions that maintain high, narrow tan δ values in the glass transition region. We begin with a base network of a trifunctional thiol and a trifunctional ene and then systematically substitute the trifunctional thiol with a series of difunctional thiols while maintaining stoichiometric balance between total thiol and ene content. The resultant ternary networks exhibit glass transition temperatures that follow the Fox equation. In contrast to other ternary thiol–ene networks, we observe minimal broadening of the glass transition region, which implies that we can retain the energy-absorbing capabilities of the thiol–ene system. This approach has high potential as a simple tool for scientists and researchers to tune T gs for select networks without detrimentally affecting other physical properties.

Dual Sulfide–Disulfide Crosslinked Networks with Rapid and Room Temperature Self‐Healability

“…The occurrence of photo-induced thiol-ene radical addition between P2-ene and TriSH was followed by FT-IR measurements. [ 24 ] The decrease in the peak area at 2570 cm −1 corresponding to SH stretching vibration before and after UV irradiation allowed for the determination of the SH consumption as a consequence of thiol-ene addition with vinyl groups of P2-ene (see the FT-IR spectrum in Figure S3 Figure S4, Supporting Information). Such decrease in both gel content and maximum G ′ modulus is presumably attributed to the formation of lightly crosslinked network with less sulfi de crosslinking density as well as coexistence of residual TriSH.…”

The Use of Click-Type Reactions in the Preparation of Thermosets

“…To develop such thiol-ene thermosets with tunable T g s, a mixture of two different thiols with different functionalities was employed. This strategy aimed to maintain desirable characteristics such as rapid kinetics of formation and high, narrow tan δ values in the glass transition region [114]. A minimal broadening of the glass transition region was observed, which implies the retention of the energy absorbing capabilities of the material with a T g that could be accurately predicted by the Fox equation.…”

Characterization of mouthguard materials: A comparison of a commercial material to a novel thiolene family

“…The resulting bonds from such reactions are flexible anti‐Markovnikov thioether linkages that are interconnected when choice starting materials are multifunctional . Amazingly this entire process approaches quantitative conversions within a matter of seconds to yield networks that are highly uniform, low‐stress, optically advantageous, have minimal chain ends and most importantly high mechanical energy damping capabilities …”