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AssigneeThe Dow Chemical Company
InventorsGeorge R. Killat, Donald A. Tomalia
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Ion exchange resins and chelate resins are provided with ion exchange or chelate capability by depositing on an insoluble substrate dense star polymers having terminal group densities greater than conventional star polymers exhibiting greater and more uniform reactivity than their corresponding conventional star polymers. For example, a third generation, amine-terminated polyamidoamine dense star polymer prepared from ammonia, methyl acrylate and ethylenediamine having 1.24.times.10.sup.-4 amine moieties per unit volume (cubic Angstrom units) in contrast to the 1.58.times.10.sup.-6 amine moieties per unit volume contained by a conventional star polymer can be reacted with a chloromethylated styrene/divinyl copolymer (insoluble substrate) to form a desirably weak base anion exchange resin.
An ion exchange resin comprising a normally solid, water-insoluble substrate having deposited thereon or chemically bonded thereto a dense star polymer in an amount effective to enable the resin to function as an ion exchange resin, said dense star polymer having at least one dendritic branch emanating from a core, each dendritic branch having at least two terminal ion exchange moieties provided that (1) the ratio of terminal groups to the branches emanating from the core is 2:1 or greater, (2) the density of terminal groups in the dense star polymer is at least 1.5 times that of an extended conventional star polymer having similar core and monomeric moieties and a comparable molecular weight and number of core branches wherein each of such branches of the extended conventional star polymer bears only one terminal group, (3) a molecular volume that is equal to or less than 80 percent of the molecular volume of said extended conventional star polymer, and (4) the two-dimensional molecular diameter of the dense star polymer is in the range from about 12 to about 2000 Angstroms.
A chelate resin comprising a normally solid, water-insoluble substrate having deposited thereon and/or chemically bonded thereto a dense star polymer in an amount effective to enable the resin to function as a chelate resin, said dense star polymer having at least one core branch emanating from a core, each core branch having at least one terminal group provided that (1) the ratio of terminal groups to the branches emanating from the core is 2:1 or greater, (2) the density of the terminal groups in the dense star polymer is at least 1.5 times that of an extended conventional star polymer having similar core and monomeric moieties and a comparable molecular weight and number of core branches wherein each of such branches of the extended conventional star polymer bears only one terminal group, (3) a molecular volume that is equal to or less than 80 percent of the molecular volume of said extended conventional star polymer, and (4) the two-dimensional molecular diameter of the dense star polymer is in the range from about 12 to about 2000 Angstroms.
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