Characterization and adsorptive properties of poly(1-vinylimidazole)/silica nanocomposites synthesized in supercritical carbon dioxide

Abstract

Poly(1-vinylimidazole) (PVIm)/silica nanocomposite particles were prepared via free radical polymerization of VIm in the presence of unmodified silica and crosslinker N,N′-methylenebisacrylamide without any surfactant by a one-pot route in supercritical carbon dioxide. The strong acid-base interaction between the hydroxyl groups (acidic) of silica surfaces and the imidazole groups (basic) of 1-VIm was strong enough to promote the formation of long-stable PVIm/silica nanocomposite particles. Transmission electron microscopy and scanning electron microscopy results showed that the silica nanoparticles were encapsulated into the polymer and with a specific pore structure. Fourier transform infrared spectroscopy results suggested the strong interaction between PVIm and silica. The nanocomposites were shown to possess higher thermal stability than PVIm. A maximum surface area of 60.76 m 2 /g was obtained via standard nitrogen adsorption analysis. The property of the composite materials in terms of heavy metal ion removal was investigated. The maximum adsorption capacity of Cr (VI) is 331.5 mg/g in the experimental range.

Synthesis of a new adsorbent poly(allylisothiocyanate‐co‐hydroxyethylmethacrylate‐co‐vinylimidazole) via photopolymerization: Characterization and investigation of heavy metal adsorption capacity

“…In Figure 5b, there has been a transition from this perforated view to a spiral view. This is due to the spherical appearance of polyvinyl imidazole, as is frequently seen in the literature 45,46 . Allylisothiocyanate, which tends to join the polymer chains more with the extension of the polymerization time, caused a morphological change in the SEM image.…”

“…This is due to the spherical appearance of polyvinyl imidazole, as is frequently seen in the literature. 45,46 Allylisothiocyanate, which tends to join the polymer chains more with the extension of the polymerization time, caused a morphological change in the SEM image. Figure 5f shows a more planar and compact structure.…”

Development of Silver-Nanoparticle-Decorated Emulsion-Templated Hierarchically Porous Poly(1-vinylimidazole) Beads for Water Treatment

“…The appearance of peaks at 1285 cm –1 (imidazole ring) and 1233 and 1146 cm –1 (polymer chain) can be attributed to C–N stretching vibrations, whereas the peaks at 1081, 964, 916, 840, 825, 737, and 664 cm –1 can further be assigned to the C–H bending vibrations of imidazole rings. ,− In PVI–Ag NCs [Figure A­(b)], the suppression of all PVI peaks was observed, accompanied by the inaccessibility of some signals at 3366, 1146, and 964 cm –1 , which may be associated with the interaction of the Ag NPs with the PVI matrix.…”

Colloidal Silica Particle Synthesis and Future Industrial Manufacturing Pathways: A Review

“…A microemulsion was then injected into the supercritical CO 2 at 35 °C, whereupon the solvent was extracted and the exposed surface of the aqueous droplets reacted with the CO 2 producing nanosized silica within the size range of 20–800 nm depending on the reactant concentrations . This process has consequently been used in the development of silica coating procedures , and silica–polymer composite synthesis …”

“…147 This process has consequently been used in the development of silica coating procedures 148,149 and silica−polymer composite synthesis. 150 More recent work has focused on developing pre-existing m i c r o e m u l s i o n s y n t h e s i s m e t h o d s f o r s p e c i fi c uses. 126,135,151−153 For example, a significant number of drug molecules are unstable in the highly basic conditions employed by most colloidal silica synthesis techniques.…”