Grafting the surface of carbon nanotubes and carbon black with the chemical properties of hyperbranched polyamines

Abstract

Controlling the chemistry on the surface of new carbon materials is a key factor to widen the range of their applicability. In this paper we show a grafting methodology of polyalkylamines to the surface of carbon nanomaterials, in particular, carbon nanotubes and a carbon black. The aim of this work is to reach large degrees of covalent functionalization with hyperbranched polyethyleneimines (HBPEIs) and to efficiently preserve the strong chelating properties of the HBPEIs when they are fixed to the surface of these carbon materials. This functionalization opens new possibilities of using these carbon nanotubes-based hybrids. The results show that the HBPEIs are covalently attached to the carbon materials, forming hybrids. These hybrids emerge from the reaction of amine functions of the HBPEIs with carbonyls and carboxylic anhydrides of the carbon surface which become imine and imide bonds. Thus, due to the nature of these bonds, the pre-oxidized samples with relevant number of C=O groups showed an increase in the degree of functionalization with the HBPEIs. Furthermore, both the acid-base properties and the coordination capacity for metal ions of the hybrids are equivalent to that of the free HBPEIs in solution. This means that the chemical characteristics of the HBPEIs have been efficiently transferred to the hybrids. To reach this conclusion we have developed a novel procedure to assess the acid-base and the coordination properties of the hybrids (solids) by means of potentiometric titration. The good agreement of the values obtained for the hybrids and for the free HBPEIs in aqueous solution supports the reliability of the procedure. Moreover, the high capacity of the hybrids to capture Ni2+ by complexation opens new possibilities of using these hybrids to capture high-value metal ions such as Pd2+ and Pt2+.

Preparation and Properties of A Hyperbranch-Structured Polyamine adsorbent for Carbon Dioxide Capture

“…Amino-terminated hyperbranched polyamine is easier to prepare compared with dendritic molecules, because it doesn’t require uniform structure and high symmetry 16 – 23 . Moreover, there are abundant amino groups which can be the adsorption sites of CO 2 in the hyperbranched polyamine.…”

Preparation and mechanical properties of water‐dispersible hyperbranched polymer grafted carbon black/natural rubber composites by latex blending method

“…However, there are still few studies on the dispersibility of hyperbranched polymer grafted CB in water. 35,36 In addition, the dispersibility of hyperbranched polymer grafted CB in natural rubber and its effect on the mechanical properties of composite have not been reported. Therefore, we can try to graft the hyperbranched polymer onto CB surface to give the CB good dispersibility in water, and blend the grafted CB dispersion with natural rubber latex by latex blending method to prepare excellent performance rubber-based composites.…”

Molecular dynamics simulations of hyperbranched poly(ethylene imine)–graphene oxide nanocomposites as dye adsorbents for water purification

“…To simulate neutral pH conditions, all carboxyl groups were taken to be deprotonated while the hydroxyl groups were not ionized 56,57 . The modified GO model, was functionalized with 4 BPEI molecules, in a manner appropriate to maintain a symmetric mass distribution with respect to the GO plane 37 . The PEI branches were partially ionized to mimic neutral pH conditions as well 35,58 .…”

“…Among them, composite GO/poly(ethylene imine) (PEI) hydrogels targeted for the removal of MB and rhodamine B (RB) organic dyes, have recently been fabricated 30 . The former family of polymers are water soluble, pH and thermal responsive and have been utilized in the past few years for the construction of carbon-based or other composite systems for environmental and biomedical purposes [31][32][33][34][35][36][37][38][39] .…”