GB2285261A - Increasing the crystallinity of aromatic ether ketone polymers with solvents - Google Patents
Increasing the crystallinity of aromatic ether ketone polymers with solvents Download PDFInfo
- Publication number
- GB2285261A GB2285261A GB9323671A GB9323671A GB2285261A GB 2285261 A GB2285261 A GB 2285261A GB 9323671 A GB9323671 A GB 9323671A GB 9323671 A GB9323671 A GB 9323671A GB 2285261 A GB2285261 A GB 2285261A
- Authority
- GB
- United Kingdom
- Prior art keywords
- membrane
- compound
- volatile
- crystallinity
- daltons
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229920000642 polymer Polymers 0.000 title claims abstract description 26
- -1 aromatic ether ketone Chemical class 0.000 title claims abstract description 8
- 239000002904 solvent Substances 0.000 title description 6
- 239000012528 membrane Substances 0.000 claims abstract description 60
- 238000000034 method Methods 0.000 claims abstract description 35
- 150000001875 compounds Chemical class 0.000 claims abstract description 26
- 239000000203 mixture Substances 0.000 claims abstract description 8
- 230000002708 enhancing effect Effects 0.000 claims abstract description 7
- 229920001643 poly(ether ketone) Polymers 0.000 claims description 21
- 238000011282 treatment Methods 0.000 claims description 11
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 9
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 claims description 9
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 9
- 239000004696 Poly ether ether ketone Substances 0.000 claims description 7
- JUPQTSLXMOCDHR-UHFFFAOYSA-N benzene-1,4-diol;bis(4-fluorophenyl)methanone Chemical compound OC1=CC=C(O)C=C1.C1=CC(F)=CC=C1C(=O)C1=CC=C(F)C=C1 JUPQTSLXMOCDHR-UHFFFAOYSA-N 0.000 claims description 7
- 229920002530 polyetherether ketone Polymers 0.000 claims description 7
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 claims description 6
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims description 6
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical group ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 claims description 4
- WERYXYBDKMZEQL-UHFFFAOYSA-N butane-1,4-diol Chemical compound OCCCCO WERYXYBDKMZEQL-UHFFFAOYSA-N 0.000 claims description 4
- 238000009835 boiling Methods 0.000 claims description 3
- 229920001657 poly(etheretherketoneketone) Polymers 0.000 claims description 3
- 229920001660 poly(etherketone-etherketoneketone) Polymers 0.000 claims description 3
- 229920005862 polyol Polymers 0.000 claims description 3
- 150000003077 polyols Chemical class 0.000 claims description 3
- 229920001652 poly(etherketoneketone) Polymers 0.000 claims description 2
- 239000003495 polar organic solvent Substances 0.000 claims 2
- 230000008569 process Effects 0.000 description 14
- 125000003118 aryl group Chemical group 0.000 description 13
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 10
- 238000002425 crystallisation Methods 0.000 description 7
- 230000035699 permeability Effects 0.000 description 7
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 229920001577 copolymer Polymers 0.000 description 5
- 239000011148 porous material Substances 0.000 description 5
- 238000000108 ultra-filtration Methods 0.000 description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 235000011149 sulphuric acid Nutrition 0.000 description 4
- 239000001117 sulphuric acid Substances 0.000 description 4
- 238000001879 gelation Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 150000002576 ketones Chemical class 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 229920002307 Dextran Polymers 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- UFWIBTONFRDIAS-UHFFFAOYSA-N Naphthalene Chemical compound C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 description 2
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000012736 aqueous medium Substances 0.000 description 2
- 238000000113 differential scanning calorimetry Methods 0.000 description 2
- ZUOUZKKEUPVFJK-UHFFFAOYSA-N diphenyl Chemical compound C1=CC=CC=C1C1=CC=CC=C1 ZUOUZKKEUPVFJK-UHFFFAOYSA-N 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 125000001174 sulfone group Chemical group 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 1
- AFVFQIVMOAPDHO-UHFFFAOYSA-N Methanesulfonic acid Chemical compound CS(O)(=O)=O AFVFQIVMOAPDHO-UHFFFAOYSA-N 0.000 description 1
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- 125000002619 bicyclic group Chemical group 0.000 description 1
- 235000010290 biphenyl Nutrition 0.000 description 1
- 239000004305 biphenyl Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229920003247 engineering thermoplastic Polymers 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 125000000623 heterocyclic group Chemical group 0.000 description 1
- 229920001519 homopolymer Polymers 0.000 description 1
- 229910000040 hydrogen fluoride Inorganic materials 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 231100000053 low toxicity Toxicity 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000001471 micro-filtration Methods 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 125000001624 naphthyl group Chemical group 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 238000005373 pervaporation Methods 0.000 description 1
- 239000003880 polar aprotic solvent Substances 0.000 description 1
- 239000002798 polar solvent Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000001223 reverse osmosis Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- ITMCEJHCFYSIIV-UHFFFAOYSA-N triflic acid Chemical compound OS(=O)(=O)C(F)(F)F ITMCEJHCFYSIIV-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0081—After-treatment of organic or inorganic membranes
- B01D67/0088—Physical treatment with compounds, e.g. swelling, coating or impregnation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/52—Polyethers
- B01D71/522—Aromatic polyethers
- B01D71/5222—Polyetherketone, polyetheretherketone, or polyaryletherketone
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C71/00—After-treatment of articles without altering their shape; Apparatus therefor
- B29C71/0063—After-treatment of articles without altering their shape; Apparatus therefor for changing crystallisation
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
- C08J7/02—Chemical treatment or coating of shaped articles made of macromolecular substances with solvents, e.g. swelling agents
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C71/00—After-treatment of articles without altering their shape; Apparatus therefor
- B29C71/0009—After-treatment of articles without altering their shape; Apparatus therefor using liquids, e.g. solvents, swelling agents
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Crystallography & Structural Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Polyethers (AREA)
Abstract
A method of enhancing the crystallinity of a porous membrane (particularly an asymmetric membrane) formed of an aromatic ether ketone polymer comprises treating the membrane with a mixture of (i) a volatile plasticising compound having a molecular weight of 30 to 150 daltons, and (ii) a water-soluble compound having a molecular weight of 30 to 150 daltons and a lower volatility than (i).
Description
ENHANCING MEMBRANE CRYSTALLINITY
The present invention relates to a process for enhancing the crystallinity of a porous membrane (particularly but not exclusively an asymmetric membrane) formed of an aromatic ether ketone polymer.
Aromatic ether ketone polymers (also referred to herein as an aromatic polyetherketones) are polymers in which inter-ring ether linkages and inter-ring ketone linkings together provide at least a major proportion of the linkages between aromatic units in the polymer backbone. We do not exclude the possibility that a portion of the aromatic rings may be replaced by a heterocyclic ring, eg pyridine, or a fused-ring system, e.g.
naphthalene.
Semi-crystalline aromatic polyetherketones are a family of high-performance engineering thermoplastics of exceptional stability, retaining their excellent mechanical properties of strength, stiffness and toughness at temperatures up to 3O00C.
They are moreover resistant to all conventional solvents at ambient temperatures and are highly resistant to the action of oxidising or hydrolysing agents.
Porous membranes (particularly asymmetric membranes) fabricated from aromatic polyetherketones are useful in a range of filtration applications, eg ultrafiltration, microfiltration, gas separation, pervaporation and reverse osmosis.
Processes for the production of asymmetric aromatic polyether ketone membranes are disclosed in EP-A-O 382 356 (ICI) and EP-A- 368 003 (Dow). As disclosed in these prior specifications, the process comprises forming a solution of the polymer into a desired shape and then treating the solution with a non-solvent for the polymer so as to cause gelation thereof and thus precipitation of the membrane.
Because of the insolubility of crystalline aromatic polyetherketones in conventional organic solvents (noted above), solutions of such polymers suitable for forming asymmetric membranes are obtainable only by use of strong acid solvents such as anhydrous methanesulphonic acid, trifluoromethanesulphonic acid, 98% sulphuric acid, or liquid hydrogen fluoride. Of these, 98% sulphuric acid is to be preferred on grounds of its low cost, low toxicity, and ease of handling.
The gelation is normally effected in an aqueous medium.
However, gelation in an aqueous medium of an aromatic polyetherketone solution in a strong acid such as sulphuric acid generally gives a polyetherketone membrane in which the polymer has only reached a fraction (typically one fifth to one half) of its normal level of crystallinity. The membrane therefore does not reach its full potential in terms of mechanical strength, stiffness, temperature resistance, and ability to withstand chemical and solvent attack.
This problem is recognised in EP-A-O 382 356 which proposes that the membrane be treated to enhance the crystallinity thereof. Such treatment includes heating the membrane dry above the Tg of the polymer, or treatment with a polar aprotic solvent, eg acetone, dimethylformamide, or dimethylacetamide. However, the membrane cannot be dried after such treatments without irreversible loss of permeability. Storing membrane wet is inconvenient and makes transportation difficult. It also promotes growth of micro-organisms in the membrane.
It is known (see Blundell and Osborn, Polymer, 1983, 24, 953) that crystallisable polyetherketones which have been very rapidly cooled from the melt can be obtained in an essentially non-crystalline form, and that, on heating such materials above their glass transition temperatures, a rapid and exothermic "cold-crystallisation" process is observed, leading to material containing typically 40-50% by weight of crystalline polymer.
Such a process is clearly unsuitable for crystallisation of an asymmetric ultrafiltration membrane as the temperatures required (typically 160-2000C) would dry out and possibly collapse the surface pores of the membrane, destroying its permeability.
An alternative crystallisation process has been disclosed in U.S. Patent No. 4,897,307 and involves solvent-induced crystallisation of polyetherketone articles including membranes, though crystallisation of a membrane was not in fact described.
This process involves (i) heating the article specifically at about 85-1450C in an organic liquid specifically of MW about 160320 daltons, (ii) removing the organic compound, and (iii) recovering the crystallised article. Such a process is likewise unsuitable for crystallisation of an asymmetric ultrafiltration membrane as removal of the liquid would again result in drying out and possible collapse of the surface pores of the membrane, destroying its permeability.
It is therefore an object of the present invention to provide a process for enhancing the crystallinity of an aromatic polyetherketone membrane which obviates or mitigates the abovementioned disadvantages.
According to the present invention there is provided a method of enhancing the crystallinity of a porous membrane formed of an aromatic ether ketone polymer comprising treating the membrane with a mixture of (i) a volatile plasticising compound having a molecular weight of 30 to 150 daltons, and (ii) a watersoluble compound having a molecular weight of 30 to 150 daltons and a lower volatility than (i).
The invention is particularly applicable to the treatment of a asymmetric membranes formed of an aromatic ether ketone polymer to enhance the crystallinity thereof.
By "asymmetric membrane" we mean a membrane (a) which comprises, on the side adjacent the solution to be filtered, a skin of thickness 0.02-2.0 microns supported on a substrate of thickness 25-250 microns; (b) in which both the skin and the substrate comprise the same polymer; and (c) in which the pore sizes of the substrate are greater than the pore sizes of the skin.
Preferably the (i) volatile plasticising compound and (ii) water-soluble compound each have a molecular weight of 40 to 140 daltons. Typically, the ratio by volume of (i):(ii) is 5-10:1.
If necessary or desired, the treatment mixture may also include (iii) a volatile third compound to ensure miscibility of compounds (i) and (ii). Preferably the ratio by volume of (iii):(ii) is 1-5:1.
The volatility of components (i) and (iii) is preferably such that they have a boiling point (at 1 atmosphere pressure) of less than 1800C, more preferably less than 1000C.
The method of the invention may be effected at relatively low temperatures (eg below 750 C) by immersion of the membrane in an admixture of (i), (ii) and possibly (iii). Most typically the treatment is effected at a temperature in the range 200 C750 C. Treatment times are typically in the range 5 min-5 hours.
The degree of crystallinity obtained by the treatment will generally be up to 50%, more typically up to 45%.
After crystallisation, the volatile plasticising compound and optional third compound are removed from the membrane by evaporation, leaving the low-volatility water-soluble compound in the pores of the membrane, preventing them from drying out and/or collapsing. The membrane will then re-wet spontaneously or at low pressure on contact with an aqueous feed.
The volatile plasticising compound (i) is typically a polar solvent such as chloroform (MW 120), dichloromethane (MW 85), dimethylformamide (MW 73), acetone (MW 58), or methyl ethyl ketone (MW 72). The water-soluble, low-volatility compound (ii) is typically a polyol such as diethylene glycol (MW 106), 1,4butanediol (MW 90), or glycerol (MW 92). The volatile third compound (iii) (if used) may for example be methanol (MW 32), ethanol (MW 46), or propan-1-ol (MW 60).
The process of the invention does not destroy the permeability or selectivity of the membrane. It is usually found that the process reduces the permeability of the membrane to some extent, but the selectivity of the membrane (as measured by its ability to reject solutes of a given molecular weight) is correspondingly increased. The selectivity of an ultrafiltration membrane is normally defined by a molecular weight cut-off (MWCO) which corresponds to the lowest molecular weight for which the membrane shows greater than 90% rejection. The process of the invention thus gives rise to a reduction in MWCO for a given membrane.
For an unsupported hollow-fibre polyetherketone membrane, the process of the invention produces enhanced mechanical properties; for example the pressure required to burst the membrane is significantly increased.
The treatment process of the invention is applicable to membranes formed from a wide range of aromatic polyetherketones using the procedures disclosed in EP-A-0 323 076. Examples of polymers from which the membranes may be fabricated are shown in the accompanying drawings, in which:
Figure 1 illustrates polymers chains in which the aromatic rings are joined by ether or ketone bonds ((I-VI); Figure 2 illustrates polymer chains in which a portion of the aromatic rings are joined by direct links (VII-IX)) or are bicyclic rings (X);
Figure 3 illustrates optional copolymer units bearing intercyclic -SO2-bonds (XI-XII); and
Figure 4 illustrates certain copolymers containing ketone and ether links (XV and XVII) or in addition a mixture of biphenyl and sulphone linkages (XIV and XVI).
It will be appreciated that in figures 1-4,
E represents an ether linkage; K K represents a ketone linkage; D represents a direct linkage;
m represents a meta substituted aromatic ring;
N represents a naphthalene ring;
S represents a sulphone linkage except where it is used as a prefix to the polymer trivial name where it represents "sulphonated".
We do not exclude the possibility that at least a portion of the ether linkages in the polymers illustrated in Figures 14 may be replaced by thioether linkages.
The preparation of polymers illustrated in certain Figures of the drawings are described inter alia in Journal
Macromolecular Science Review of Macromolecular Chem. Phys., (27 (2), 313-341, 1987 (General Formulae I-VIII); European Patent
Specification No. 0,323,076 (General Formula IX); Polymer 1984,
Vol 25 (August, 1151 (General Formula X); EPA 0,194,062 (General
Formulae XIV) and British Patent Application No. 8910549 (General
Formulae XVI)).
The membrane is preferably formed of a homopolymer, most preferably PEK, PEEK, PEEKK, or PEKEKK. PEK and PEEK are available from Imperial Chemical Industries plc, PEEKK from
Hoechst, and PEKEKK from BASF.
We do not however exclude the possibility that the membrane may be fabricated from a copolymer eg. PEEK/PEK, PEEK/PES,
PEK/PES, PEEK/PEES (wherein the PES and PEES copolymer units are represented by the General Formulae XI and XII respectively in
Fig. 3 of the drawings). Further examples of copolymers are as depicted in Fig. 4 of the drawings and include PEKK/PE-m-KK (Formula XVII).
Furthermore we do not exclude the possibility that the membrane may be formed from a mixture of polymers, eg. PEEK/PEK or PEK/PES.
The invention is illustrated by the following non-limiting example.
EXAMPLE
A hollow-fibre ultrafiltration membrane (internal diameter 0.6 mm; external diameter 0.8 mm) was prepared by spinning a solution of PEK in 98% sulphuric acid, as described in EP-A-0 382 356. The crystallinity level (as measured by differential scanning calorimetry) of the polyetherketone comprising the membrane was 16%. The membrane had a pure water permeability of 48 l/m2/hr/bar, a MWCO (for dextrans) of 19,000 daltons, and a burst pressure of 7.2 bar.
This membrane was treated at 560C for 30 minutes with a mixture of acetone (volatile plasticising compound, 70% by volume), glycerol (water-soluble, low volatility compound, 10% by volume), and methanol (miscibility-enhancing compound, 20% by volume). The membrane was then removed from the liquid and allowed to dry in air for 24 hours.
The crystallinity level of the treated membrane (measured by differential scanning calorimetry) of the polyetherketone comprising the membrane was now 40%. The treated membrane had a pure water permeability of 32 l/m2/hr/bar, a MWCO (for dextrans) of 12,000 daltons, and a burst pressure of 10.6 bar.
Claims (17)
1. A method of enhancing the crystallinity of a porous membrane formed of an aromatic ether ketone polymer comprising treating the membrane with a mixture of (i) a volatile plasticising compound having a molecular weight of 30 to 150 daltons, and (ii) a water soluble compound having a molecular weight of 30 to 150 daltons and a lower volatility than (i).
2. A method as claimed in claim 1 wherein the volatile plasticising compound (i) has a molecular weight of 40 to 140 daltons.
3. A method as claimed in claim 1 or 2 wherein the volatile plasticising compound (i) is a polar organic solvent.
4. A method as claimed in any one of claims 1 to 3 wherein the volatile plasticising compound has a boiling point of less than 1800C.
5. A method as claimed in claim 3 wherein the polar organic solvent is selected from chloroform, dichloromethane, dimethylformamide, acetone and methyl ethyl ketone.
6. A method as claimed in any one of claims 1 to 5 wherein the water soluble compound (ii) has a molecular weight of 40 to 140 daltons.
7. A method as claimed in any one of claims 1 to 6 wherein the ratio by volume of (i) to (ii) is 5-10:1.
8. A method as claimed in any one of claims 1 to 7 wherein the water soluble compound (ii) is a polyol.
9. A method as claimed in claim 8 wherein the polyol is selected from diethylene glycol, 1, 4-butane diol and glycerol.
10. A method as claimed in any one if claims 1 to 9 wherein a volatile third compound (iii) is included in the mixture to ensure miscibility of components (i) and (ii).
11. A method as claimed in claim 10 wherein compound (iii) has a boiling point less than 1800C.
12. A method as claimed in claim 10 or 11 wherein the ratio by volum of (iii) to (ii) is 1-5:1.
13. A method as claimed in any one of claims 1 to 12 wherein the treatment is effected at a temperature of less than 750C.
14. A method as claimed in claim 13 wherein the treatment is effected at a temperature of 200C to 750C.
15. A method as claimed in any one of claims 1 to 14 wherein the aromatic ether ketone polymer is PEK, PEEK, PEEKK, PEKEKK or
PEKK/PE-m-KK.
16. A method as claimed in any one of claims 1 to 15 wherein the membrane is an asymmetric membrane.
17. A method of enhancing the crystallinity of a porous membrane substantially as hereinbefore described in the foregoing example.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9323671A GB2285261B (en) | 1993-11-17 | 1993-11-17 | Enhancing membrane crystallinity |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9323671A GB2285261B (en) | 1993-11-17 | 1993-11-17 | Enhancing membrane crystallinity |
Publications (3)
Publication Number | Publication Date |
---|---|
GB9323671D0 GB9323671D0 (en) | 1994-01-05 |
GB2285261A true GB2285261A (en) | 1995-07-05 |
GB2285261B GB2285261B (en) | 1997-10-08 |
Family
ID=10745294
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9323671A Expired - Fee Related GB2285261B (en) | 1993-11-17 | 1993-11-17 | Enhancing membrane crystallinity |
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GB (1) | GB2285261B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2002077068A2 (en) * | 2001-03-28 | 2002-10-03 | Fuma-Tech Gmbh | Sulfonated polyetherketoneketone |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0285377A2 (en) * | 1987-03-30 | 1988-10-05 | Kureha Kagaku Kogyo Kabushiki Kaisha | Preparation of highly crystallized, molded polyarylene thioether products |
-
1993
- 1993-11-17 GB GB9323671A patent/GB2285261B/en not_active Expired - Fee Related
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0285377A2 (en) * | 1987-03-30 | 1988-10-05 | Kureha Kagaku Kogyo Kabushiki Kaisha | Preparation of highly crystallized, molded polyarylene thioether products |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2002077068A2 (en) * | 2001-03-28 | 2002-10-03 | Fuma-Tech Gmbh | Sulfonated polyetherketoneketone |
WO2002077068A3 (en) * | 2001-03-28 | 2002-11-14 | Fuma Tech Gmbh | Sulfonated polyetherketoneketone |
US6984713B2 (en) | 2001-03-28 | 2006-01-10 | FuMa-Tech Gesellschaft fur funktionelle Membranen und Anlagentechnologie mbH | Sulfonated polyetherketoneketone |
Also Published As
Publication number | Publication date |
---|---|
GB2285261B (en) | 1997-10-08 |
GB9323671D0 (en) | 1994-01-05 |
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Effective date: 19991117 |