Economical synthesis of functional aromatic polythioamides from KOH-assisted multicomponent polymerizations of sulfur, aromatic diamines and dialdehydes

Abstract

Polythioamides with fascinating properties such as unique metal ion coordination ability, excellent thermal stability, good solubility, and high refractive index have attracted much attention recently, but their synthesis remains challenging, especially for aromatic polythioamides. In this work, multicomponent polymerizations of elemental sulfur, aromatic diamines, and aromatic dialdehydes with wide and economical sources were developed with the assistance of KOH. The polymerizations featured commercially available monomers with low cost, general applicability to various diamine and dialdehyde monomers, feasibility of large-scale synthesis, high atom economy, and no release of harmful byproducts, producing a series of aromatic polythioamides with high molecular weights of up to 54 700 g mol⁻¹ and high yields of up to 96%. These polythioamides generally exhibited excellent thermal stability, good solubility, high thin film-light refractivity of 1.87 at 633 nm, and could be used for gold extraction. The MCP has provided an economical and efficient method to access unique aromatic polythioamides on a large scale, accelerating the exploration of sulfur-containing polymers as high-performance functional polymer materials.