Synthesis of morphologically different, metal absorbing aniline‐formaldehyde polymers including micron‐sized sphere using simple alcohols as morphology modifier

Abstract

Aniline-formaldehyde condensate (AFC) is an amine functional group containing polymer. The sticky resinous nature of the polymer limits its usefulness. Synthesis of AFC in presence of methanol, isopropanol, t-butanol, n-octanol or glycerine formed solid cakes instead of resinous material. The scanning electron microscopic (SEM) picture of the polymer synthesized in presence of t-butanol shows the formation of micron sized spheroids while the presence of methanol, isopropanol, n-octanol and glycerine leads to amorphous polymer. The polymers were characterized with IR, MALDI-TOF mass and Energy Dispersive Xray (EDAX) analysis. To probe the accessibility of the amine functional groups by external reagents and as an application, metal removal property of the polymers were tested using aqueous Cr(VI) solution. All the polymers remove Cr(VI) efficiently at pH 3 with extent of metal removal depends on their morphology. Polymer synthesized in presence of isopropanol removes $ 66% Cr(VI) removal from an initial concentration of 9 mg/L.

Effect of molecular structure of aniline–formaldehyde copolymers on corrosion inhibition of mild steel in hydrochloric acid solution

“…The bands at 1512 cm -1 and 821 cm -1 can be assigned to the stretching vibration of benzenoid framework and the bending vibration of substituted benzene ring, respectively. The absorption bands at 1615 cm -1 and 1267 cm -1 are assigned to -NH and -C-N-stretching vibrations, respectively, while the characteristic band observed at 3345 cm -1 indicates that the copolymers contain primary and/or secondary amine functional groups [32,35,40,41]. However, changes in the IR spectra of as-synthesized copolymers occurred with a decrease in the molar ratio of aniline to formaldehyde.…”

“…Condensation polymerization of aniline and formaldehyde involves electrophilic addition of protonated formaldehyde to the ortho-and/or para-position of aniline depending on the ratios of aniline to formaldehyde [34,35]. The linear or cross-linked structure of the resultant polymer depends on the reaction stoichiometry, pH and temperature.…”

“…to formaldehyde in the polymerization solutions on the adsorption capability of as-prepared AFCs has been investigated with regard to heavy metal ions, including copper and hexavalent chromium [35][36][37]. To the best of our knowledge, the effect of molar ratio of aniline to formaldehyde in the polymerization solution on corrosion inhibition efficiency of as-prepared AFCs has not been reported.…”

Synthesis and Thermal and Textural Characterization of Aniline Formaldehyde-Organoclay Composites

“…The effect of -CH 2 -linkages in the aniline-formaldehyde resin can be determined with the polymerization of aniline formaldehyde conducted under the acidic condition. Since any spherical texture in the composites prepared in this study was not observed, it can be concluded that the -CH 2 -linkage plays a main role in the aniline sphere formation [20]. The extent of crystalline character depends on the acidic nature of the monomers [21].…”

Polymers for the Extraction of Chromium—Role of Polymers in the Removal and Recovery of Chromium from Wastewater

“…The addition of formaldehyde to aniline in acidic medium forms a rubbery thermoplastic resin spontaneously, which is known as aniline formaldehyde condensate (AFC). It is extremely used in adhesive industry and also useful to bind Cr(VI) effectively in acid medium (74). AFC is effective even at low concentration of Cr(VI) (9 mg. L −1 ) and reduces Cr(VI) level by 70% at pH 3 (74).…”