Grafting and phosphonic acid functionalization of hyperbranched polyamidoamine polymer onto ultrafine silica

Abstract

In this study, grafting of hyperbranched polyamidoamine (PAMAM) polymer onto ultrafine silica followed by functionalization via the introduction of phosphonic acid groups into the branch ends was performed. First, an initiating site was incorporated into the silica surface by reacting the silica silanol group with 3-aminopropyltriethoxysilane, producing amino-functionalized silica. The free amine group content was altered by varying the ratio of methanol to water in the hydrolysis step of the silanization reaction. Grafting of PAMAM was attained by three rounds of sequential Michael addition of silica amino groups to methyl acrylate and amidation of the resulting terminal methyl ester groups with ethylenediamine. Completion of the grafting reaction in each step was clearly confirmed using FTIR analysis. Excessive ethylenediamine and unattached hyperbranched PAMAM present in the reaction product were removed by dialysis with a molecular weight cutoff of 6000-7000 Daltons. However, the amino group content determined in each step was found to be significantly lower than theoretically expected, perhaps indicative of side reactions and, in later stages, steric hindrance. The resultant hyperbranched PAMAM-grafted onto silica was functionalized by phosphorylation of the terminal amino groups by a Mannich type reaction, producing the phosphorylated hyperbranched PAMAM-grafted silica. Then its application on cotton fabric to produce fireretardant cellulose was tentatively investigated.

Effect of Surface Functionality of Silica Nanoparticles on Cellular Uptake and Cytotoxicity

“…The 13,41,42 The peaks observed after methyl modification at 2964 cm −1 can be attributed to C−H vibration, and the band of peaks at 1255, 848, and 758 cm −1 can be attributed to Si−CH 3 of methyl group from TMCS. 38,43 The sharp peak displayed by pure curcumin at 3507 cm −1 and a broad peak at 3293 cm −1 are attributed to −OH group vibrations without and with intermolecular hydrogen bonding, respectively.…”

Modulating in vitro release and solubility of griseofulvin using functionalized mesoporous silica nanoparticles

“…The silanol peak disappeared when amino and methyl modifications are performed on MCM-41. The amino modification resulted in appearance of peaks at 2929, 1626 and 1518 cm À1 which can be attributed to C-H stretching, N-H bending and N-H stretching vibrations of aminopropyl group anchored on the surface of MCM-41 [13,44,45]. The methyl modification results in the peak at 2962 cm À1 which can be attributed to C-H vibration and band of peaks at 1255, 848 and 758 cm À1 attributed to Si-CH 3 of methyl group from TMCS [42,46].…”

Efficient and Ecofriendly Route for the Solvent-Free Synthesis of 4-Alkoxy-5H-chromen[2,3-d]pyrimidines Using Phosphonic Acid Functionalized KIT-6 Confined Ionic Liquid as Recoverable Catalyst

“…a straightforward Mannich-type reaction [19] between phosphorous acid and imine (from reaction between primary amine in aminopropyl functionalized KIT-6 and formaldehyde) in the presence of excess amount of concentrated HCl. Then the IL@[phosphonicacid@KIT-6] was prepared by filling the 3D mesochannels of phosphonic acid functionalized KIT-6 with [BMIm][BF 4 ] (Scheme 1).…”

“…The average pore diameter, which estimated from the TEM images, was about 7.5 nm, which agreed well with that from the N 2 sorption and XRD analysis. [19,20] Then the potential efficiency of [BMIm] [BF 4 ]@[phosphonicacid@KIT-6] as an organic-inorganic nanohybrid catalyst was assessed in the synthesis of 4-alkoxy-5H-chromen [2,3-d]pyrimidines under different conditions. The catalytic performance and selectivity of [BMIm] [BF 4 ]@[phosphonicacid@KIT-6] was evaluated in the synthesis of 4-methoxy-5H-chromen [2,3-d]pyrimidines via the three-component condensation between 2-imino-2H-chromene-3-carbonitrile, salicylaldehyde, and malononitrile as a model reaction.…”