New synthetic methods for the formation of basic, polyvalent, hyperbranched grafts

practical synthetic route to polybasic, polyamine, hyperbranched grafts using commercially available polyethyleneimine (PEI) and cyanuric chloride as a coupling agent is described. The grafting process was followed by XPS spectroscopy, TGA analysis, ATR-IR spectroscopy, acid-base titration, and by C-13 CP-MAS NMR spectroscopy. In the case of silica gel, thermal gravimetric analyses showed that a 35 wt % loading of graft could be obtained. Acid-base titration of hyperbranched PEI grafts on silica gel and oxidized polyethylene powder showed the ion-exchange capacities of these PEI-grafted substrates were 1.00 and 0.17 mmol of base/g of solid, respectively. Although the focus of the paper is on grafting on silica gel, the influence of the kind of support and solvent on the grafting process and the ion-exchange capacity was examined. Water was a good solvent for PEI grafting onto silica gel, but a more hydrophobic polyethylene support required the use of dichloromethane as a solvent for PEI graft synthesis. (c) 2005 Wiley Periodicals, Inc.