Green Synthesis of Sulfur-Containing Polymers by Carbon Disulfide-based Spontaneous Multicomponent Polymerization

Abstract

Sulfur-containing polymers have gained much attention in polymer science due to their unique properties. Nevertheless, their preparation has posed considerable challenges, particularly in diversifying their structures and achieving highly efficient polymerizations. This is especially true for the polymers derived from CS2, a readily available one-carbon (C1) feedstock, as their synthesis often necessitates harsh conditions or results in unexpected byproducts. In this work, we established a regio-selective and atom-economy spontaneous multicomponent polymerization based on carbonyl or ester group-activated internal alkynes, commercially available amines, and CS2. Similar to the angled half lap joint of two plates in a scarf joint of in ancient Chinese tenon and mortise architecture, these internal ethynyl and amino groups can not readily react at room temperature. However, the addition of CS2 acts as a "wedge," making the polymerization spontaneous and enabling the tight linkage and extension of these functional groups into stable polymer chains. The sulfur-containing polymers with satisfactory weight-average molecular weights (up to 31 600) were produced in high yields (up to 97%). The resultant polymers exhibit exceptional characteristics, including high refractive indices (up to 1.7471 at 632.8 nm), excellent light transmittance, and good film-forming capabilities. This work opens up a new avenue for the green and efficient synthesis of functional sulfur-containing polymers, using cost-effective CS2 as starting material.