Modified dense star polymers
AssigneeThe Dow Chemical Company
InventorsDonald A. Tomalia, James R. Stahlbush
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Abstract
Dense star polymers on immobilized cores are very useful as ion-exchange resins and chelation resins. For example, an aminated form of chloromethylated styrene/divinyl benzene copolymer can be employed as an immobilized core compound and reacted successively with methyl acrylate via a Michael addition reaction and then with ethylenediamine to form a first generation dense star polymer or dendrimer. These reactions can then be repeated to form second and third generation dendrimers.
Claims9
An improved dense star polymer prepared in a reaction medium having at least one branch emanating from an immobilized core which core and its precursor are insoluble in the reaction medium in which the dense star polymer is prepared, said branch called a core branch having at least two terminal groups provided that (1) the ratio of terminal groups to the core branches is more than one, (2) the density of terminal groups per unit volume in the 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, each of such branches of the extended conventional star polymer bearing only one terminal group, and (3) a molecular volume that is no more than about 80 percent of the molecular volume of said extended conventional star polymer as determined by dimensional studies using scaled Core-Pauling molecular models.
Dependencies are inferred from the claim text.