1,3,5-hexahydro-1,3,5-triazines (HTs) and their thermosetting polymer analogues, PHTs, have attracted recent attention in the materials space as they exhibit a number of attractive properties such as healability, facile preparation of anti-microbial surfaces and even as detectors for heavy metals. HTs also demonstrate unique reactivity towards sulfur containing compounds. Organic thiols will react with HTs to produce thioaminals, a transformation that was recently exploited to generate a new class of linear step-growth polymers, polythioaminals. The synthesis of polythioaminals are tolerant to a variety of substituents, functional groups and monomers. For example, aliphatic dithiols, dithioerthritol and polyether dithiols can all be polymerized. One limiting factor is the HT substituent, where as the size increases the molecular weight of the polymer decreases and only high molecular weight polymers were generated with short aliphatic HT substituents, restricting the chemical diversity of the resulting polymers. There are alternative chemistries that can provide access to polythioaminals not restricted by the volatility of a side product and may provide access to more chemically diverse polymers. Herein, we present an alternative synthetic strategy to access polythioaminals using the in-situ generation of imines as reactive intermediates from aromatic amines containing electron-withdrawing groups (EWGs) – known to form imines in the presence of aldehydes. Low molecular weight linear polythioaminals could be produced by this method. Furthermore, it was found the dyntamic nature of the thioaminal bond allowed the conversion of these linear aromatic polythioaminals to network polymers by the undergoing multiple substitutions at the aminal linkage at increased temperatures. This property is an attractive feature for easy to process highly fluorinated polymers with applications that include hydrophobic coatings currently under investigation for tailorable surface topology for antifouling coatings for medical devices.

Synthesis of polythioaminals using in-situ generated imines as reactive intermediates: Polymers for tailorable surface topology

253rd National Meeting (2017)

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