Preparation of crosslinked porous polyurea microspheres in one-step precipitation polymerization and its application for water treatment

Abstract

Porous polyurea microspheres (PPUMs) were prepared in one-step by the precipitation polymerization of isophorone diisocyanate (IPDI) in a water–acetone solvent. Monodisperse SiO₂ particles were added before polymerization and etched by a crosslinking agent triethylenetetramine (TETA), which led to the arrangement of the pores on the crosslinked polyurea microspheres' surface. Another method was also tested for the synthesis of PPUMs, in which non-crosslinked polyurea/SiO₂ composite microspheres were synthesized first, and the SiO₂ nanoparticles were then etched away. Compared to the second way, the one-step method is simple and efficient. The crosslinked PPUMs showed excellent hydrophilicity. The influence of the amounts of SiO₂ nanoparticles, TETA, and the size of SiO₂ nanoparticles were studied. The adsorption tests for iodine and methyl orange (MO) dyes in water were carried out, which showed that the as-prepared crosslinked PPUMs possessed great adsorption performance.