Polysulfide-ene polymerization of bisacrylamides and bismaleimides toward sulphur-rich polymers

Abstract

Given the ever-increasing importance of developing more sustainable solutions for the fabrication and engineering of polymeric materials, alternative building blocks to the petroleum-derived chemicals are gaining growing interest. In addition to its natural abundance, elemental sulfur is produced industrially in vast quantities which is primarily obtained as a side product from oil refineries and gas purification plants. Thus, elemental sulfur has been prospected as a sustainable resource for the fabrication of structurally diverse polymers. In this study an efficient methodology to obtain sulfur-rich polymers from elemental sulfur-derived polysulfide salts is reported. Polysulfide-ene step growth polymerization of bisacrylamide and bismaleimide-based monomers with bifunctional disodium pentasulfide (Na₂S₅) generated structurally diverse polyamide and polyimide copolymers incorporating polysulfide chains on the polymer backbones. Copolymers up to 31.8 kDa molecular weight (M_n) and 94% monomerconversions were efficiently obtained under ambient temperature conditions and without the need of any metal or organo-catalyst. By choosing various bifunctional ene monomers, structurally diverse and tailorable linear copolymers were obtained. The methodology was also extended to the fabrication of sulfur-rich crosslinked polymers by employing a multifunctional thiolate-based crosslinker. As a potential application, fabricated crosslinked polymers were employed as adsorbents to remove toxic mercury ions from water. The reported synthetic strategy demonstrated the efficiency of polysulfide-ene reaction to synthesize sulfur-rich polyamide and polyimide polymers and could broaden the available polymerization reaction tools that employelemental sulfur-derived polysulfide salts in functional polymer synthesis.

Graphical abstract

Keywords:

• Sulfur-richpolymers
• polysulfide-ene polymerization
• polysulfides
• cross-linked polymers
• mercury removal

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The raw/processed data required to reproduce these findings cannot be shared at this time due to legal or ethical reasons.