Effect of Isocyanate Index on the Dye Removal Efficiency of Polyurethane Foams Absorbents

Abstract

Here, the impact of isocyanate index (90, 100, and 110) on the dye elimination efficiency of the polyurethane foams (PUFs) was investigated. FPUF were manufactured by polyester resin and methylene diphenyl diisocyanate and assessed by atomic force microscopy ‎‎(AFM), optical microscopy, morphological, chemical reaction rate, and‏ ‏dye removal adsorption analysis to evaluate the correlation between their dye removal efficiency and morphological characteristics. The results disclosed that by increasing the isocyanate index from 90 to 110, chemical reaction rates decreased and the cell size (30.88%), open-cell content (34.6%), cell wall roughness (41%), and dye removal efficiency (140.9%) increased. The increased dye removal is attributed to the higher roughness and open-cell content. Accordingly, PUFs with an optimum cell wall roughness and open-cell content can be considered for dye wastewater treatment.