Bridged dense star polymers
First Claim
1. A bridged dense star polymer comprising at least two dense star polymer molecules connected by a covalent linkage, such dense star polymer molecules which prior to bridging have 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 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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Accused Products
Abstract
Bridged dense star polymers having terminal group densities greater than conventional extended star polymers exhibit greater and more uniform reactivity than their corresponding conventional star polymers. For example, a third generation, hydroxy-terminated polyether dense star polymer can be prepared from pentaerythrityltetrabromide and 4-hydroxymethyl-2,6,7-trioxabicyclo[2.2.2]-octane which has a molecular volume less than 80 percent of the volume of a conventional extended star polymer made from similar materials. This dense star polymer can then be bridged by reacting it with a suitable difunctional reactant such as toluene diisocyanate. Such polymers of dense star polymers are useful as demulsifiers for oil/water emulsions, wet strength agents in the manufacture of paper, proton scavengers, calibration standards for electron microscopy, and agents for modifying viscosity in aqueous formulations such as paints.
215 Citations
32 Claims
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1. A bridged dense star polymer comprising at least two dense star polymer molecules connected by a covalent linkage, such dense star polymer molecules which prior to bridging have 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 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.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 11, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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8. A bridged dense star polymer which comprises at least two dendrimer molecules which are covalently bonded together and which molecules are represented by the formula:
- ##EQU7## wherein ○
is a polyfunctional core, Zc is a functional group bonded to the core and a X group of the first generation, Nc is the number of functional group bonded to the core, Xi is a monofunctional tail of a repeating unit Yi of the i generation which is bonded to Yi and a Z group of the i-1 generation, Zi is a functional group bonded to Yi and a X group of the i+1 generation, Ni is a number of at least 2 which corresponds to the multiplicity of the polyfunctional head of Yi, π
is the product function, Ni-1 is a number of at least 2 which corresponds to the multiplicity of the polyfunctional head of Yi-1 wherein Yi-1 is a repeating unit of the Yi-1 generation, Xt is the monofunctional tail of a repeating unit Yt of the terminal generation, Zt is a terminating group bonded to Yt, Nt is zero or a number which corresponds to the number of Zt groups bonded to one Yt group, i represents a number of a particular generation in a series from 1 to a number from 1 to t-1, provided that (1) all Xi Yi (Zi)N i are the same within a generation and are the same or different in different generations and (2) all Xt Yt (Zt)N t of the terminal generation are the same. - View Dependent Claims (9, 10, 12, 13, 14)
- ##EQU7## wherein ○
Specification