US4199448A
Expired / Lapsed
US
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Reverse osmosis membrane of high urea rejection properties
Assignee: National Aeronautics and Space Administration
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Filing: 1976-06-09
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Granted: 1980-04-22
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Expires: 1996-06-09
Abstract
Abstract Polymeric membranes suitable for use in reverse osmosis water purification because of their high urea and salt rejection properties are prepared by generating a plasma of an unsaturated hydrocarbon monomer and nitrogen gas from an electrical source and forming a polymeric membrane by depositing a polymer of said unsaturated monomer from said plasma onto a substrate, such that nitrogen from the nitrogen gas is incorporated within the polymer in a chemically combined form.
Inventors
- 👤 Catherine C. Johnson
- 👤 Theodore J. Wydeven
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:42
CPC Classifications
B; B01; B01D; B01D69/00; B01D69/12; B01D69/125; B01D69/127
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
72 words
A method for preparing polymeric membranes of high urea and salt rejection characteristics, which comprises: generating a plasma of ethylene and nitrogen in an RF field having a power within the range of about 15 to about 35 watts; forming a polymeric membrane by depositing a polymer of ethylene from said plasma onto a substrate, such that nitrogen from the nitrogen gas is incorporated within the polymer in a chemically combined form.
Claim 2
Independent Claim
72 words
A method for preparing polymeric membranes of high urea and salt rejection characteristics, which comprises: generating a plasma of ethylene and nitrogen in an RF field having a power within the range of about 15 to about 35 watts; forming a polymeric membrane by depositing a polymer of ethylene from said plasma onto a substrate, such that nitrogen from the nitrogen gas is incorporated within the polymer in a chemically combined form.
Claim 3
Dependent Claim
20 words
The method of claim 1, wherein said unsaturated hydrocarbon monomer is an alkene, an alkyne, a cyclic or heterocyclic compound.
Claim 4
Dependent Claim
21 words
The method of claim 1, wherein the flow rate of nitrogen into said plasma ranges from 1 to 2 cc (STP)/min.
Claim 5
Dependent Claim
23 words
The method of claim 1, wherein the flow rate of said unsaturated monomer into said plasma ranges from 1 to 2 cc (STP)/min.
Claim 6
Dependent Claim
19 words
The method of claim 1, wherein the power of the RF field which generates said plasma is 15 watts.
Claim 7
Dependent Claim
30 words
The method of claim 1, wherein the pressure of said unsaturated monomer ranges from 0.1 to 0.4 torr and the pressure of said nitrogen ranges from 0.1 to 0.4 torr.
Claim 8
Dependent Claim
19 words
The method of claim 1, wherein said nitrogen and unsaturated monomer are mixed prior to entry into said plasma.
Claim 9
Dependent Claim
16 words
The membrane of claim 7, wherein said polymeric material contains 15 to 22 wt % nitrogen.
Claim 10
Dependent Claim
23 words
The method of claim 1, wherein said plasma is created by an internal capactively coupled discharge at a radio frequency of 13.56 MHz.
Claim 11
Dependent Claim
17 words
A reverse osmosis membrane containing nitrogen in chemically combined form prepared by the process of claim 1.
Claim 12
Dependent Claim
29 words
A process for purifying aqueous wastes containing salt and urea, which comprises: subjecting said aqueous waste to reverse osmosis over a membrane prepared by the process of claim 1.
Claim 13
Independent Claim
152 words
An apparatus for the plasma activated polymerization of unsaturated monomers in the presence of nitrogen, which comprises: a glass cross reactor comprising four glass tubes, wherein an open end of each tube is joined to form a common center for all four tubes; a pair of electrodes disposed within said reactor each through one of the four tubes of the reactor and sealed from the external environment of the reactor and coupled to a radio frequency source so as to generate a plasma within the reactor; means for introducing and controlling the inflow of a gaseous mixture of an unsaturated monomer and nitrogen into the reactor through an unoccupied sealed tube of the reactor; means for evacuating the glass cross reactor; and means for controlling the pressure of the gaseous mixture within the reactor, wherein said evacuating and controlling means are attached to said reactor through the remaining tube of the reactor.
Claim 14
Independent Claim
152 words
An apparatus for the plasma activated polymerization of unsaturated monomers in the presence of nitrogen, which comprises: a glass cross reactor comprising four glass tubes, wherein an open end of each tube is joined to form a common center for all four tubes; a pair of electrodes disposed within said reactor each through one of the four tubes of the reactor and sealed from the external environment of the reactor and coupled to a radio frequency source so as to generate a plasma within the reactor; means for introducing and controlling the inflow of a gaseous mixture of an unsaturated monomer and nitrogen into the reactor through an unoccupied sealed tube of the reactor; means for evacuating the glass cross reactor; and means for controlling the pressure of the gaseous mixture within the reactor, wherein said evacuating and controlling means are attached to said reactor through the remaining tube of the reactor.
Claim 15
Dependent Claim
27 words
The apparatus of claim 12, wherein one of said electrodes functions as a support within the reactor for collecting said polymerized material and is at ground potential.
Claim 16
Dependent Claim
17 words
The apparatus of claim 12, wherein said plasma is created by a radio frequency of 13.56 MHz.
Claim 17
Dependent Claim
14 words
The apparatus of claim 12, wherein said pressure control means is a throttling valve.
Claim 18
Dependent Claim
17 words
The apparatus of claim 12, wherein each of said electrodes is a 9 cm O.D. copper electrode.
Claim 19
Dependent Claim
64 words
The apparatus of claim 12, wherein said means for introducing and controlling a gaseous mixture into said reactor is a sequence of a shut off valve, a mass flow tranducer and flow control valve each in a line from a source of nitrogen and unsaturated monomer which lines are joined together prior to entry into said reactor to mix said nitrogen and unsaturated monomer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-04-22 | 1983-10-22 | 1984-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-22 | 1987-10-22 | 1988-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-22 | 1991-10-22 | 1992-04-22 | $7700.00 | Window Closed / Lapsed |