The synthesis of degradable sulfur-containing polymers: precise control of structure and stereochemistry

Sulfur-containing polymers are polymers containing at least one sulfur atom in the repeat units of their main chains. The incorporation of sulfur atoms into the polymer main chains endows polymers with enhanced properties in many areas, including improved mechanical properties, optical properties, thermal properties, and adhesive abilities toward metal ions. Such enhanced properties make sulfur-containing polymers promising polymeric materials. In terms of environmental issues caused by waste plastic, the utilization of sulfur-containing polymers is also appealing from the aspect of degradability. Hence, degradable sulfur-containing polymers, including poly(thiocarbonate)s, poly(thioester)s, and poly(sulfite)s, are drawing more and more attention. However, the synthesis of these polymers involves problems like mixed structures and weak stereochemistry control of the resultant polymers due to the intrinsic properties of sulfur atoms, such as strong nucleophilicity and coordinative abilities. Thus, tackling the problems caused by sulfur chemistry is the main challenge relating to the precise synthesis of sulfur-containing polymers. Herein, this review describes recent progress made regarding the precise synthesis of sulfur-containing polymers from the perspectives of structure control, stereochemistry control, and topological structure modification.