A novel and easy one-step protocol for preparation of a new porous material, polyurea (PPU), is reported, which is accomplished through a precipitation polymerization of toluene diisocyanate (TDI) in mixed solvent of H2O-acetone without need for surfactant and porogen. Effects of TDI concentration, mechanical stirring, solvent composition and TDI addition rate on PPU structure are studied. Surface morphology and pore structure of PPU are characterized by scanning electron microscopy and Hg intrusion. Chemical structure of the PPU polymer is investigated using NMR, XRD and FTIR. Mechanism of pore formation is discussed. The obtained PPU is used as adsorbent for anionic dyes adsorption investigation. Two anionic dyes, remazol brilliant blue R and acid fuchsine, are tested. The results indicate that the as-prepared PPU is of high performance in dye adsorption and recycled use. This study provided therefore a facile route to the preparation of a novel and attractive adsorbent candidate for removal of anionic dyes from wastewaters.

A novel type of hollow polymer particles, polyurea (PU) microspheres with uniform morphology, is prepared via precipitation polymerization of isophorone diisocyanate (IPDI) in acetone–H2O as the solvent in three steps. In the first step, IPDI reacts with H2O to form the core particles consisting of linear PU, followed, in the second step, by addition of triethylene tetramine (TETA) and supplementary IPDI; the microspheres of core–shell structure are therefore obtained with a shell consisting of crosslinked PU thanks to the copolymerization of TETA with IPDI. Hollow microspheres are finally obtained by dissolving the core template of linear PU. The influence of the amounts of TETA, IPDI and their molar ratio on the formation and the morphology of the core–shell and the hollow microspheres are studied. The morphologies of the core–shell and of the hollow microspheres are characterized by scanning electron microscopy. The polymers are examined using Fourier-transform infrared spectra, differential scanning calorimetry and thermogravimetric analysis.