Membranes
First Claim
1. A solution comprising a sulphonated polyaryletherketone and a solvent mixture which contains at least three components each of which is a non-solvent or poor solvent for the sulphonated polyaryletherketone and which are(a) a liquid or a low melting solid containing at least one hydroxylic group and having a delta-H with a value of at least 8;
- (b) a liquid or a low melting solid having a delta-D with a value of at least 8 and a delta-P with a value of not more than 3; and
(c) a liquid or a low melting solid having a delta-P with a value of at least 8.5 and a delta-H with a value of not more than 3;
wherein the solvent mixture forms a single liquid phase and none of the components of the solvent mixture reacts or complexes with another of the components of the solvent mixture or with the sulphonated polyaryletherketone.
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Abstract
Solutions of sulphonated polyaryletherketones in a solvent mixture of at least three liquids or low melting solids which are non-solvents or poor solvents for the polymer, can be used to produce asymmetric semi-permeable membranes. The polymer may be a polymer of
(Ph.sup.1 --O--Ph.sup.2 --O--Ph.sup.1 --CO)
and optionally
(Ph.sup.1 --O--Ph.sup.1 --CO)
and
(Ph.sup.1 --O--Ph.sup.1 --O--Ph.sup.1 --CO)
wherein Ph1 and Ph2 are respectively unsulphonated and sulphonated phenylene residues. The components of the solvent mixture have specified solubility parameters. A suitable solvent mixture is one formed from water, 1,4-dioxane and acetonitrile.
30 Citations
7 Claims
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1. A solution comprising a sulphonated polyaryletherketone and a solvent mixture which contains at least three components each of which is a non-solvent or poor solvent for the sulphonated polyaryletherketone and which are
(a) a liquid or a low melting solid containing at least one hydroxylic group and having a delta-H with a value of at least 8; -
(b) a liquid or a low melting solid having a delta-D with a value of at least 8 and a delta-P with a value of not more than 3; and (c) a liquid or a low melting solid having a delta-P with a value of at least 8.5 and a delta-H with a value of not more than 3; wherein the solvent mixture forms a single liquid phase and none of the components of the solvent mixture reacts or complexes with another of the components of the solvent mixture or with the sulphonated polyaryletherketone. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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3. The solution of claim 2 wherein the sulphonated polyaryletherketone is a material in which the value of m is only one or is only two or is a material in which the value of m differs along the polymer chain and is both one and two at various points along the chain.
- 4. The solution of claim 1 wherein the sulphonated polaryletherketone is the product obtained by sulphonating a polymer having the repeat units of the formula
- space="preserve" listing-type="equation">(Ph.sup.1 --O--Ph.sup.1 --O--Ph.sup.1 --CO) IA
and optionally also including comonomer units of the formula
space="preserve" listing-type="equation">(Ph.sup.1 --O--Ph.sup.1 --Y) IIor comonomer units of the formula
space="preserve" listing-type="equation">(Ph.sup.1 --O--Ph.sup.1 --O--Ph.sup.1 --SO.sub.2) IIIwherein Ph1 is a phenylene residue; and
;Y is a --CO-- or --SO2 -- group, and the nature of Y in the units of formula II may vary.
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5. The solution of claim 1 in which component (a) of the solvent mixture has a delta-H of at least 8, a delta-D of not more than 8 and a delta-P of at least 6;
- component (b) of the solvent mixture has a delta-D of at least 8, a delta-P of not more than 3 and a delta-H of not more than 4; and
component (c) of the solvent mixture has a delta-P of at least 8.5, a delta-H of not more than 3 and a delta-D of at least 7.5.
- component (b) of the solvent mixture has a delta-D of at least 8, a delta-P of not more than 3 and a delta-H of not more than 4; and
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6. The solution of claim 5 wherein the solvent mixture contains at least 20% by weight of 1,4-dioxane, at least 10% by weight of acetonitrile and not more than 40% by weight of water, the total amounts of the three components aggregating to 100% by weight.
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7. The solution of claim 1 wherein at least one component of the solvent mixture is volatile and evaporates, at least partially, during casting of the solution.
Specification