Ultrathin polyphenylene oxide polymer films and their preparation
First Claim
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1. A process for preparing a polyphenylene oxide polymer film having a thickness of 400 angstroms or less and having no holes about one micron or more in diameter wherein the process comprises:
- (a) preparing a polymer solution containing a polyphenylene oxide polymer, having a molecular weight, Mw, greater than about 1000, at about the two to about the twelve percent level, based upon the total weight of the casting solution, in a mixture of chlorinated solvents;
(b) depositing the polymer solution on about 60 to about 85 percent aqueous ortho-phosphoric acid to form a free-standing film; and
(c) removing the film from the aqueous ortho-phosphoric liquid.
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Abstract
Disclosed herein are free-standing, pinhole-free, ultrathin, polyphenylene oxide films having thicknesses of about 400 angstroms or less and a process for preparing them. The films find particular utility in separatory applications.
9 Citations
23 Claims
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1. A process for preparing a polyphenylene oxide polymer film having a thickness of 400 angstroms or less and having no holes about one micron or more in diameter wherein the process comprises:
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(a) preparing a polymer solution containing a polyphenylene oxide polymer, having a molecular weight, Mw, greater than about 1000, at about the two to about the twelve percent level, based upon the total weight of the casting solution, in a mixture of chlorinated solvents; (b) depositing the polymer solution on about 60 to about 85 percent aqueous ortho-phosphoric acid to form a free-standing film; and (c) removing the film from the aqueous ortho-phosphoric liquid. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 19, 20, 21, 23)
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2. A process for preparing a polyphenylene polymer film having a thickness of about 400 angstroms or less and having no holes about one micron or more in diameter wherein the process comprises:
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(a) preparing a casting solution containing a polyphenylene oxide polymer having a molecular weight, Mw, greater than about 1000 and having repeating units of the general formula;
##STR2## wherein R and R'"'"' may be the same or different and are hydrogen atoms, halogen atoms, substituted and unsubstituted hydrocarbon groups, halohydrocarbons, alkoxy groups or phenoxy groups, at about the two to about the twelve percent by weight level, based upon the total weight of the casting solution, in about a 4;
6 to about a 6;
4 by volume ratio of trichloroethylene;
1,2,3-trichloropropane or trichloroethylene;
1,1,2,2-tetrachloroethane;(b) depositing the casting solution on about 60 to about 85 percent aqueous ortho-phosphoric acid to form a free-standing film; (c) removing the film from the ortho-phosphoric acid. - View Dependent Claims (17, 18, 22)
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3. A process for preparing a polyphenylene oxide polymer film having a thickness of about 400 angstroms or less and having no holes about one micron or more in diameter wherein the process comprises:
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(a) preparing a casting solution containing a poly(2,6-dimethyl-p-phenylene oxide) polymer having a molecular weight, Mw, greater than about 1000 at about the two to about the twelve percent by weight level, based upon total weight of the casting solution, in about a 1;
1 by volume ratio of trichloroethylene;
1,2,3-trichloropropane or trichloroethylene 1,1,2,2-tetrachloroethane;(b) depositing the casting solution on about 60 to about 70 percent by weight aqueous ortho-phosphoric acid to form a free-standing film; and (c) removing the film from the ortho-phosphoric acid.
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Specification