Morales-Lara Francisco, Domingo-García María, López-Garzón Rafael, Luz Godino-Salido María, Peñas-Sanjuán Antonio, López-Garzón F Javier, Pérez-Mendoza Manuel, Melguizo Manuel
Dpto. de Química Inorgánica, Facultad de Ciencias, Universidad de Granada , Granada , Spain.
Dpto. de Química Inorgánica y Orgánica, Facultad de Ciencias Experimentales, Universidad de Jaén , Jaén , Spain.
Sci Technol Adv Mater. 2016 Sep 12;17(1):541-553. doi: 10.1080/14686996.2016.1221728. eCollection 2016.
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 Ni by complexation opens new possibilities of using these hybrids to capture high-value metal ions such as Pd and Pt.
控制新型碳材料表面的化学性质是拓宽其应用范围的关键因素。在本文中，我们展示了一种将聚烷基胺接枝到碳纳米材料表面的方法，特别是碳纳米管和炭黑。这项工作的目的是实现与超支化聚乙烯亚胺（HBPEI）的高度共价功能化，并在将HBPEI固定到这些碳材料表面时有效保持其强螯合性能。这种功能化开启了使用这些基于碳纳米管的杂化物的新可能性。结果表明，HBPEI共价连接到碳材料上，形成了杂化物。这些杂化物源于HBPEI的胺官能团与碳表面的羰基和羧酸酐的反应，形成了亚胺键和酰亚胺键。因此，由于这些键的性质，具有相关数量C=O基团的预氧化样品显示出与HBPEI功能化程度的增加。此外，杂化物的酸碱性质和对金属离子的配位能力与溶液中游离的HBPEI相当。这意味着HBPEI的化学特性已有效地转移到了杂化物中。为了得出这一结论，我们开发了一种通过电位滴定来评估杂化物（固体）酸碱和配位性质的新方法。杂化物和水溶液中游离HBPEI所获得的值的良好一致性支持了该方法的可靠性。此外，杂化物通过络合捕获镍的高能力开启了使用这些杂化物捕获钯和铂等高价值金属离子的新可能性。
