Fructose-Based Non-Isocyanate Polyurethane/Poly (Sodium Acrylate) Hydrogels: Design, Synthesis and Environmental Applications

Abstract

Conventional methods for synthesising polyurethane hydrogels encompass toxic isocyanates and organic solvents, limiting their eco-friendliness and ease of synthesis. In response, this study introduces an innovative approach to synthesising fructose-based non-isocyanate polyurethane (NIPU) hydrogel (FNHG), eliminating the need for isocyanates. Initially, fructose-based NIPU (FNPU) was synthesised using dimethyl carbonate and hexamethylene diamine under mild reaction conditions, paving the way for a greener polyurethane variant. Subsequently, a free radical polymerization technique was employed in an aqueous medium. This process allowed for the integration of poly(sodium acrylate), and N, N-methylene bisacrylamide, leading to to the development of FNHG. Remarkably short gelation time of just 30 min at 60 ℃ was achieved, signifying a significant advancement in the synthesis process. The synthesized NIPU-based hydrogels exhibited outstanding efficiency in the removal of crystal violet (CV) and malachite green (MG) dyes from aqueous media. With an impressive removal efficiency of 96.87% for CV and an astounding 99.8% for MG, these hydrogels demonstrated high effectiveness in remediation efforts. The study’s novelty lies in both the synthesis methodology, utilising FNPU, and the exceptional efficiency exhibited by these hydrogels in eliminating diverse dyes from contaminated water. Furthermore, the structure of FNPU was confirmed using FTIR and ¹H NMR spectroscopy, adding robustness to our findings. This research not only presents a solution to the limitations of traditional polyurethane synthesis but also demonstrates the potential of fructose-based NIPU hydrogels (FNHG) as eco-friendly and efficient agents for water purification.

Graphical Abstract