US4910233A
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Process for crosslinking methylene-containing aromatic polymers with ionizing radiation
Assignee: United States, AS REPRESENTED BY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
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Filing: 1986-03-11
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Granted: 1990-03-20
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Expires: 2006-03-11
Abstract
Abstract The invention relates to a process for crosslinking aromatic polymers containing radiation-sensitive methylene groups (-CH2-) by exposing the polymers to ionizing radiation thereby causing crosslinking of the polymers through the methylene groups. Crosslinked polymers are resistant to most organic solvents such as acetone, alcohols, hydrocarbons, methylene, chloride, chloroform, and other halogenated hydrocarbon, to common fuels and to hydraulic fluids in contrast to readily soluble uncrosslinked polymers. In addition, the degree of crosslinking of the polymers depends upon the percentage of the connecting groups which are methylene which ranges from 5 to 50% and preferably from 25 to 50% of the connecting groups and is also controlled by the level of irradiation which ranges from 25 to 1000 Mrads and preferably from 25 to 250 Mrads. The temperature of the reaction conditions ranges from 25 DEG to 200 DEG C. and preferably at or slightly above the glass transition temperature of the polymer. The crosslinked polymers are generally more resistant to degradation at elevated temperatures such as greater than 150 DEG C., have a reduced tendency to creep under load and show no significant embrittlement of parts fabricated from the polymers.
Inventors
- 👤 Vernon L. Bell
- 👤 Stephen J. Havens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:57
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/28; C08F; C08F8/00
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
32 words
A process for crosslinking methylene containing aromatic polymers with ionizing radiation, which comprises: forming an aromatic polymer having methylene connecting groups; and crosslinking the methylene connecting groups of the polymer by irradiation.
Claim 2
Dependent Claim
32 words
A process for crosslinking methylene containing aromatic polymers with ionizing radiation, which comprises: forming an aromatic polymer having methylene connecting groups; and crosslinking the methylene connecting groups of the polymer by irradiation.
Claim 3
Dependent Claim
32 words
A process for crosslinking methylene containing aromatic polymers with ionizing radiation, comprising: providing an aromatic polymer containing methylene connecting groups; and crosslinking the methylene connecting groups of the aromatic polymer by irradiation.
Claim 4
Dependent Claim
32 words
A process for crosslinking methylene containing aromatic polymers with ionizing radiation, comprising: providing an aromatic polymer containing methylene connecting groups; and crosslinking the methylene connecting groups of the aromatic polymer by irradiation.
Claim 5
Dependent Claim
26 words
The process according to claim 2, wherein the aromatic polymer contains no aliphatic hydrocarbon segments within the main chain of the polymer except the methylene groups.
Claim 6
Dependent Claim
25 words
The process according to claim 2, wherein the aromatic polymers are selected from the group consisting of aromatic polyesters, aromatic polysulfones, poly(ether sulfones) and polyethers.
Claim 7
Dependent Claim
22 words
The process according to claim 1, wherein the aromatic polyesters have benzene moieties connected by a number of ester and methylene groups.
Claim 8
Dependent Claim
20 words
The process according to claim 1, wherein the methylene connecting groups and other connecting groups are present in equal numbers.
Claim 9
Dependent Claim
13 words
The process according to claim 1, wherein the aromatic polymer is poly(2,6-dimethylphenylene oxide).
Claim 10
Dependent Claim
27 words
The process according to claim 4, wherein the aromatic polysulfones, poly(ether sulfones) and polyethers have aromatic rings interspersed only with methylene, ether oxygen, 2,2-isopropylidene and sulfone groups.
Claim 11
Dependent Claim
28 words
The process according to claim 4, wherein the aromatic polysulfones, poly(ether sulfones) and polyethers have aromatic rings interspersed only with methylene and ether oxygen, 2,2-isopropylidene or sulfone groups.
Claim 12
Dependent Claim
51 words
The process according to claim 2, comprising: preparing the aromatic polyester by polymerizing 3,3'-methylenedibenzoyl chloride with 4,4'-isopropylidene diphenol using an interfacial polymerization technique; dissolving the polyester in a solvent to form a polyester solution; casting the solution onto a support; evaporating the solvent; and exposing the polyester to an electron dose.
Claim 13
Dependent Claim
23 words
The process according to claim 2, wherein the polymer is irradiated with about 70 KeV electrons at about a 15 Mr/hr dose rate.
Claim 14
Dependent Claim
29 words
The process according to claim 2, wherein the aromatic polyester has about 50% of the connecting groups being methylene groups and is synthesized by reacting 3,3'-methylenedibenzoyl chloride with 4,4'-methylenediphenol.
Claim 15
Dependent Claim
29 words
The process according to claim 2, wherein the aromatic polyester has about 50% of the connecting groups being methylene groups and is synthesized by reacting 4,4'-methylenedibenzoyl chloride with 3,3'-methylenediphenol.
Claim 16
Dependent Claim
29 words
The process according to claim 2, wherein the aromatic polyester has about 50% of the connecting groups being methylene groups and is synthesized by reacting 3,3'-methylenedibenzoyl chloride with 3,3'-methylenediphenol.
Claim 17
Dependent Claim
23 words
The process according to claim 2, wherein irradiation of the aromatic polymer is at or above the glass transition point of the polymer.
Claim 18
Dependent Claim
14 words
The process according to claim 2, wherein the irradiating dose is about 250 Mr.
Claim 19
Dependent Claim
11 words
The process according to claim 2, wherein no oxygen is present.
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